kth.sePublications
Change search
Refine search result
123456 1 - 50 of 276
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Ala-Laurinaho, J.
    et al.
    Aalto University, Finland.
    Chicherin, Dmitry
    Aalto University, Finland.
    Du, Zhou
    Aalto University, Finland.
    Simovski, C.
    Aalto University, Finland.
    Zvolensky, T.
    Aalto University, Finland.
    Räisänen, Antti V.
    Aalto University, Finland.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Baghchehsaraei, Zargham
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Dudorov, Sergey
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Boriskin, A. V.
    IETR, France.
    Le Coq, L.
    IETR, France.
    Fourn, Erwan
    IETR, France.
    Muhammad, S. A.
    IETR, France.
    Sauleau, Ronan
    IETR, France.
    Vorobyov, Alexander
    IETR, France.
    Bodereau, F.
    TRW Autocruise, France.
    El Haj Shhade, G.
    TRW Autocruise, France.
    Labia, T.
    TRW Autocruise, France.
    Mallejac, P.
    TRW Autocruise, France.
    Åberg, Jan
    MicroComp Nordic AB, Sweden.
    Gustafsson, M.
    MicroComp Nordic AB, Sweden.
    Schier, T.
    MicroComp Nordic AB, Sweden.
    TUMESA - MEMS tuneable metamaterials for smart wireless applications2012In: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012, IEEE , 2012, p. 95-98Conference paper (Refereed)
    Abstract [en]

    This paper describes the main results of the EU FP7 project TUMESA - MEMS tuneable metamaterials for smart wireless applications. In this project, we studied several reconfigurable antenna approaches that combine the new technology of MEMS with the new concept of artificial electromagnetic materials and surfaces (metamaterials and metasurfaces) for realisation of millimetre wave phase shifters and beam-steering devices. MEMS technology allows to miniaturise electronic components, reduce their cost in batch production, and effectively compete with semiconductor and ferroelectric based technologies in terms of losses at millimetre wavelengths. Novel tuneable materials and components proposed in this project perform as smart beam steering devices. Fabricated with MEMS technology in batch and on a single chip, proposed tuneable devices allow substituting of larger and more complex sub-system of, e.g., a radar sensor. This substitution provides a dramatic cost reduction on a system level.

  • 2.
    An, Sining
    et al.
    Chalmers University of Technology.
    Pettersson, Victor
    Veoneer Sweden AB.
    Karimi, Armin
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Simon He, Zhongxia
    Chalmers University of Technology.
    Zirath, Herbert
    Chalmers University of Technology.
    Automotive In-Cabin Object Detection and Passenger Monitoring with Sub-THz Radar System2023Conference paper (Refereed)
    Abstract [en]

    In this paper, an H-band radar system is built, and measurement of in-cabin object detection and passenger monitoring is demonstrated to better understand the in-cabin propagation environment at sub-THz frequencies.

    Download full text (pdf)
    fulltext
  • 3.
    Anoshkin, Ilya V.
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Lioubtchenko, Dmitri V.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Freeze-Dried Carbon Nanotube Aerogels for High-Frequency Absorber Applications2018In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, ISSN 1944-8244, Vol. 10, no 23, p. 19806-19811Article in journal (Refereed)
    Abstract [en]

    A novel technique for millimeter wave absorber material embedded in a metal waveguide is proposed. The absorber material is a highly porous carbon nanotube (CNT) aerogel prepared by a freeze-drying technique. CNT aerogel structures are shown to be good absorbers with a low reflection coefficient, less than -12 dB at 95 GHz. The reflection coefficient of the novel absorber is 3-4 times lower than that of commercial absorbers with identical geometry. Samples prepared by freeze-drying at -25 degrees C demonstrate resonance behavior, while those prepared at liquid nitrogen temperature (-196 degrees C) exhibit a significant decrease in reflection coefficient, with no resonant behavior. CNT absorbers of identical volume based on wet-phase drying preparation show significantly worse performance than the CNT aerogel absorbers prepared by freeze-drying. Treatment of the freeze-dried CNT aerogel with n- and p-dopants (monoethanolamine and iodine vapors, respectively) shows remarkable improvement in the performance of the waveguide embedded absorbers, reducing the reflection coefficient by 2 dB across the band.

    Download full text (pdf)
    fulltext
  • 4. Arsanjani, Arash
    et al.
    Mehrabi Gohari, Mohammad
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    A Silicon Micromachined Cascaded Singlet Filtering Antenna at 270 GHzManuscript (preprint) (Other academic)
    Abstract [en]

    This paper discusses the steps and challenges of implementing a cascaded singlet filtenna using silicon deep reactive ion etching (DRIE) technology. Two fourth-order filtennas with a center frequency of 270~GHz, 14~GHz bandwidth, and a 20~dB inband return loss are fabricated and measured to verify the proposed concept. The measured single-slot and dual-slot filtenna have a peak radiation gain of X~dBi, and Y~dBi at 270~GHz, respectively. Moreover, the challenges and details of silicon micromachining in fabricating these antennas are discussed.Comprehensive details regarding the synthesis procedure, confirmation via simulation, and measurement outcomes are thoroughly explained.

  • 5.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    MEMS-reconfigurable irises for millimeter-wave waveguide componentsManuscript (preprint) (Other academic)
  • 6.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    MEMS-reconfigurable wavguide iris for switchable V-band cavity resonators2014In: 2014 IEEE 27th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE , 2014, p. 206-209Conference paper (Refereed)
    Abstract [en]

    This paper presents for the first time a novel MEMS-reconfigurable inductive iris based on a 30-μm thick reconfigurable transmissive surface and reports on its application to create a switchable cavity resonator in a WR-12 rectangular waveguide (60-90 GHz). The reconfigurable surface incorporates 252 simultaneously switched contact points for activating (ON state) and deactivating (OFF state) the inductive iris by a 24 μm lateral displacement of two sets of distributed vertical cantilevers. In the ON state, these contact points are short-circuiting the electric field lines of the TE10 waveguide mode on the cross-sectional areas of a symmetric inductive waveguide iris, and are not interfering with the wave propagation in the OFF state. Thus, this novel concept allows for completely switching the inductive iris ON or OFF. The inductive iris has an insertion loss of better than 1.0 dB in the OFF state, of which 0.8 dB is attributed to the measurement setup alone. In the ON state the measured performance of the switchable iris is in good agreement with the simulation results. Furthermore, a novel, switchable cavity resonator was implemented based on such a MEMS-reconfigurable iris, and was characterized to a Q-factor of 186.13 at the resonance frequency of 68.87 GHz with the iris switched ON, and an OFF-state insertion loss of less than 2 dB (including the measurement setup) without any resonance, which is for the first time reported in this paper.

  • 7.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Parameter Analysis of Millimeter-Wave Waveguide Switch Based on a MEMS-Reconfigurable Surface2013In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 61, no 12, p. 4396-4406Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel concept of a millimeter-wave waveguide switch based on amicroelectromechanical (MEMS)-reconfigurable surface with insertion loss and isolation very similar to high performance but bulky rotary waveguide switches, despite its thickness of only 30 mu m. A set of up to 1470 micromachined cantilevers arranged in vertical columns are actuated laterally by on-chip integrated MEMS comb-drive actuators, to switch between the transmissive state and the blocking state. In the blocking state, the surface is reconfigured so that the wave propagation is blocked by the cantilever columns short-circuiting the electrical field lines of the TE10 mode. A design study has been carried out identifying the performance impact of different design parameters. The RF measurements (60-70 GHz) of fabricated, fully functional prototype chips show that the devices have an isolation between 30 and 40 dB in the OFF state and an insertion loss between 0.4 and 1.1 dB in the ON state, of which the waveguide-assembly setup alone contributes 0.3 dB. A device-level yield analysis was carried out, both by simulations and by creating artificial defects in the fabricated devices, revealing that a cantilever yield of 95% is sufficient for close-to-best performance. The actuation voltage of the active-opening/active-closing actuators is 40-44 V, depending on design, with high reproducibility of better than (sigma = 0.0605 V). Lifetime measurements of the all-metal, monocrystalline-silicon core devices were carried out for 14 h, after which 4.3 million cycles were achieved without any indication of degradation. Furthermore, a MEMS-switchable waveguide iris based on the reconfigurable surface is presented.

  • 8.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    V-Band Single-Pole-Single-Throw Mems Rectangular waveguide Switch2013In: MME 2013 24th Micromechanics and Microsystems Europe Conference, 2013Conference paper (Refereed)
    Abstract [en]

    This paper presents a concept of a waveguide single-pole single-throw (SPST) switch based on a MEMS-reconfigurable surface. A set of vertical columns, split into two groups of movable and fixed sections which can be actuated laterally by integrated MEMS comb-drive actuators, allows for the transition between the transmissive and the blocking state. In the totally-blocking state, the vertical columns inhibit the wave propagation by short-circuiting the electrical field lines of the predominantTE10 mode. The paper reports on the integration method for fabricated chips into a WR-12 waveguide by using tailor-made flanges. The RF measurement of fabricated chips show that devices have better than 30 dB isolation in the OFF state and better than 0.65 dB insertion loss in the ON state for60-70 GHz, which is mainly attributed to the integration into the waveguide and the measurement assembly setup. The actuation voltage is 44 V, and lifetime measurements were carried out for 14 hours after which 4.3 million cycles were achieved without any indication on degradation.

  • 9. Baghchehsaraei, Zargham
    et al.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Dudorov, Sergey
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Aberg, Jan
    MEMS 30 µm-thick W-band Waveguide Switch2012In: 2012 42ND EUROPEAN MICROWAVE CONFERENCE (EUMC), IEEE , 2012, p. 1055-1058Conference paper (Refereed)
    Abstract [en]

    This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30 µm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.

  • 10.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Dudorov, Sergey
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Åberg, Jan
    MEMS 30μm-thick W-band waveguide switch2012In: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 42nd European Microwave Conference, EuMC 2012, Institute of Electrical and Electronics Engineers (IEEE) , 2012, p. 1055-1058, article id 6459114Conference paper (Refereed)
    Abstract [en]

    This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30μm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.

  • 11.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Dudorov, Sergey
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Åberg, Jan
    MEMS 30μm-thick W-band Waveguide Switch2012In: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012, European Microwave Association , 2012, p. 675-678Conference paper (Refereed)
    Abstract [en]

    This paper presents for the first time a novel concept of a MEMS waveguide switch based on a reconfigurable surface, whose working principle is to short-circuit or to allow for free propagation of the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. This transmissive surface is only 30μm thick and consists of up to 1260 reconfiguring cantilevers in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. For the first fabrication run, the yield of these reconfigurable elements on the chips was 80-86%, which still was good enough for resulting in a measured insertion loss in the open state of better than 1dB and an isolation of better than 20dB for the best designs, very wideband from 62 to 75GHz. For 100% fabrication yield, HFSS simulations predict that an insertion loss in the open state of better than 0.1dB and an isolation of better than 30dB in the closed state are possible for designs with 800 and more contact points for this novel waveguide switch concept.

    Download full text (pdf)
    fulltext
  • 12.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Åberg, J.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Millimeter-Wave SPST Waveguide Switch Based on Reconfigurable MEMS Surface2013In: 2013 IEEE MTT-S International Microwave Symposium Digest (IMS), IEEE , 2013, p. 6697774-Conference paper (Refereed)
    Abstract [en]

    This paper presents a concept of a waveguide single-pole single-throw (SPST) switch based on a MEMSreconfigurable surface. A set of vertical columns, split into two groups of movable and fixed sections which can be actuated laterally by integrated MEMS comb-drive actuators, allows for the transition between the transmissive and the blocking state. In the totally-blocking state, the vertical columns inhibit the wave propagation by short-circuiting the electrical field lines of the predominant TE10 mode. The paper reports on the integration method for fabricated chips into a WR-12 waveguide by using tailor-made flanges. The RF measurement of fabricated chips show that devices have better than 30 dB isolation in the OFF state and better than 0.65 dB insertion loss in the ON state for 60-70 GHz, which is mainly attributed to the integration into the waveguide and the measurement assembly setup. The actuation voltage is 44 V, and life-time measurements were carried out for 14 hours after which 4.3 million cycles were achieved without any indication on degradation.

  • 13.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Åberg, Jan
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    MEMS reconfigurable millimeter-wave surface for V-band rectangular-waveguide switch2013In: International Journal of Microwave and Wireless Technologies, ISSN 1759-0787, Vol. 5, no 3, p. 341-349Article in journal (Refereed)
    Abstract [en]

    This paper presents for the first time a novel concept of a microelectromechanical systems (MEMS) waveguide switch based on a reconfigurable surface, whose working principle is to block the wave propagation by short-circuiting the electrical field lines of the TE10 mode of a WR-12 rectangular waveguide. The reconfigurable surface is only 30 mu m thick and consists of up to 1260 micro-machined cantilevers and 660 contact points in the waveguide cross-section, which are moved simultaneously by integrated MEMS comb-drive actuators. Measurements of fabricated prototypes show that the devices are blocking wave propagation in the OFF-state with over 30 dB isolation for all designs, and allow for transmission of less than 0.65 dB insertion loss for the best design in the ON-state for 60-70 GHz. Furthermore, the paper investigates the integration of such microchips into WR-12 waveguides, which is facilitated by tailor-made waveguide flanges and compliant, conductive-polymer interposer sheets. It is demonstrated by reference measurements where the measured insertion loss of the switches is mainly attributed to the chip-to-waveguide assembly. For the first prototypes of this novel MEMS microwave device concept, the comb-drive actuators did not function properly due to poor fabrication yield. Therefore, for measuring the OFF-state, the devices were fixated mechanically.

  • 14.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Åberg, Jan
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Integration of microwave MEMS devices into rectangular waveguide with conductive polymer interposers2013In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 12, p. 125020-Article in journal (Refereed)
    Abstract [en]

    This paper investigates a novel method of integrating microwave microelectromechanical systems (MEMS) chips into millimeter-wave rectangular waveguides. The fundamental difficulties of merging micromachined with macromachined microwave components, in particular, surface topography, roughness, mechanical stress points and air gaps interrupting the surface currents, are overcome by a double-side adhesive conductive polymer interposer. This interposer provides a uniform electrical contact, stable mechanical connection and a compliant stress distribution interlayer between the MEMS chip and a waveguide frame. The integration method is successfully implemented both for prototype devices of MEMS-tuneable reflective metamaterial surfaces and for MEMS reconfigurable transmissive surfaces. The measured insertion loss of the novel conductive polymer interface is less than 0.4 dB in the E-band (60-90 GHz), as compared to a conventional assembly with an air gap of 2.5 dB loss. Moreover, both dc biasing lines and mechanical feedthroughs to actuators outside the waveguide are demonstrated in this paper, which is achieved by structuring the polymer sheet xurographically. Finite element method simulations were carried out for analyzing the influence of different parameters on the radio frequency performance.

  • 15. Baghchehsaraei, Zargham
    et al.
    Vorobyov, Alexander
    IETR (Institut d’Electronique et de Télécommunications de Rennes), Université de Rennes.
    Sauleau, Ronan
    IETR (Institut d’Electronique et de Télécommunications de Rennes), Université de Rennes.
    Fourn, Erwan
    IETR (Institut d’Electronique et de Télécommunications de Rennes), INSA de Rennes.
    Oberhammer, Joachim
    PHASED-ARRAY ANTENNA BASED ON MEMS FIN-LINE PHASESHIFTERS FOR W-BAND BEAM-STEERING APPLICATIONS2012In: GigaHertz Symposium 2012, 2012Conference paper (Refereed)
    Abstract [en]

    This paper presents phased array antenna, which consists of 21×10 integrated phase shifter elements, as a beam steeringdevice for automotive radar applications.

    Download full text (pdf)
    Abstract
  • 16.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Vorobyov, Alexander
    Åberg, Jan
    Fourn, Erwan
    Sauleau, Ronan
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Waveguide-integrated MEMS-based phase shifter for phased array antenna2014In: IET Microwaves, Antennas & Propagation, ISSN 1751-8725, E-ISSN 1751-8733, Vol. 8, no 4, p. 235-243Article in journal (Refereed)
    Abstract [en]

    This study investigates a new concept of waveguide-based W-band phase shifters for applications in phased array antennas. The phase shifters are based on a tuneable bilateral finline bandpass filter with 22 microelectromechanical system (MEMS) switching elements, integrated into a custom-made WR-12 waveguide with a replaceable section, whose performance is also investigated in this study. The individual phase states are selected by changing the configuration of the switches bridging the finline slot in specific positions; this leads to four discrete phase states with an insertion loss predicted by simulations better than 1 dB, and a phase shift span of about 270°. MEMS chips have been fabricated in fixed positions, on a pair of bonded 300 µm high-resistivity silicon substrates, to prove the principle, that is, they are not fully functional, but contain all actuation and biasing-line elements. The measured phase states are 0, 56, 189 and 256°, resulting in an effective bit resolution of 1.78 bits of this nominal 2 bit phase shifter at 77 GHz. The measured insertion loss was significantly higher than the simulated value, which is assumed to be attributed to narrow-band design of the devices as the influences of fabrication and assembly tolerances are shown to be negligible from the measurement results.

  • 17.
    Baghchehsaraei, Zargham
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Åberg, Jan
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Mems-reconfigurable millimeter-wave surfaces for waveguide switches, irises and resonators2014In: The GigaHertz 2014 Symposium, 2014Conference paper (Refereed)
    Abstract [en]

    This paper presents a concept and prototypes of transmissive millimeter-wave surfaces, which are reconfigurable by integrated micro-electromechanical (MEMS) actuators. The surfaces consist of small vertical elements which can be configured so that they are vertically connected and thus they short-circuit the electrical field lines in the waveguide, which results in total blocking of the wave propagation, or that they are not connected which results in full wave propagation through the surface.

  • 18.
    Bartlett, Chad
    et al.
    Univ Kiel, Dept Elect & Informat Engn, D-24118 Kiel, Germany..
    Mehrabi Gohari, Mohammad
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Hoft, Michael
    Univ Kiel, Dept Elect & Informat Engn, D-24118 Kiel, Germany..
    Compact Triangular-Cavity Singlet-Based Filters in Stackable Multi-Layer Technologies2022In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 12, no 5, p. 540-543Article in journal (Refereed)
    Abstract [en]

    In this letter, triangular-cavity bandpass filters are investigated in stackable multilayer technologies in order to achieve highly compact designs with reduced fabrication complexity. The triangular-shaped cavities are first introduced in the form of singlets and then expanded on as a novel method for achieving a quasi-triplet filter response, where the filter's input and output irises are utilized as resonating means for two additional passband poles. Exploitation of this advanced singlet scheme exemplifies innovative use of resonant irises for achieving highly compact filters that can be manufactured with simple multilayer fabrication steps for use in future terahertz applications.

    Download full text (pdf)
    fulltext
  • 19.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    A CPW Probe to Rectangular Waveguide Transition for On-wafer Micromachined Waveguide CharacterizationManuscript (preprint) (Other academic)
    Abstract [en]

    A new transition from coplanar waveguide probe to micromachined rectangular waveguide for on-wafer device characterization is presented in this article. The transition is fabricated in the same double H-plane split silicon micromachined waveguide technology as the devices under test, requiring no additional post-processing or assembly steps. We outline the design and fabrication process of the transition for the frequency band of 220 – 330 GHz. A coplanar waveguide structure acts as the probing interface, with an E-field probe protruding in the waveguide cavity exciting the fundamental waveguide mode. Guard structures around the E-field probe increase the aspect ratio during deep reactive ion etching and secure its geometry. A full equivalent circuit model is provided by analyzing its working principle. RF characterization of fabricated devices is performed for both single-ended and back-to-back configurations. Measured S-parameters of the single-ended transition are obtained by applying a two-tiered calibration and are analyzed using the equivalent circuit model. The insertion loss of the single-ended transition lies between 0.3 dB and 1.5 dB over the whole band, with the return loss in excess of 8 dB. In addition to previously reported characterization of a range of devices under test the viability of the transition for on-wafer device calibration is demonstrated by characterizing a straight waveguide line, achieving an insertion loss per unit length of 0.02 – 0.08 dB/mm in the frequency band of 220 – 330 GHz.

  • 20.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    A CPW Probe to Rectangular Waveguide Transition for On-Wafer Micromachined Waveguide Characterization2024In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 14, no 1, p. 98-108Article in journal (Refereed)
    Abstract [en]

    A new transition from coplanar waveguide probe to micromachined rectangular waveguide for on-wafer device characterization is presented in this article. The transition is fabricated in the same double H-plane split silicon micromachined waveguide technology as the devices under test, requiring no additional post-processing or assembly steps. We outline the design and fabrication process of the transition for the frequency band of 220–330 GHz. A coplanar waveguide structure acts as the probing interface, with an E-field probe protruding in the waveguide cavity exciting the fundamental waveguide mode. Guard structures around the E-field probe increase the aspect ratio during deep reactive ion etching and secure its geometry. A full equivalent circuit model is provided by analyzing its working principle. RF characterization of fabricated devices is performed for both single-ended and back-to-back configurations. Measured S-parameters of the single-ended transition are obtained by applying a two-tiered calibration and are analyzed using the equivalent circuit model. The insertion loss of the single-ended transition lies between 0.3 dB and 1.5 dB over the whole band, with the return loss in excess of 8 dB. In addition to previously reported characterization of a range of devices under test the viability of the transition for on-wafer device calibration is demonstrated by characterizing a straight waveguide line, achieving an insertion loss per unit length of 0.02–0.08 dB/mm in the frequency band of 220–330 GHz.

    Download full text (pdf)
    fulltext
  • 21.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    On-wafer Micromachined Waveguide Characterization with CPW Probe to Rectangular Waveguide Transition up to 500 GHzManuscript (preprint) (Other academic)
    Abstract [en]

    We report on coplanar waveguide to micromachined waveguide transitions for on-wafer device characterization. The transitions are designed in a silicon micromachined waveguide technology using silicon on insulator wafers together with the devices under test. A previous design at 220–330 GHz with in-band radiation characteristic is modified to eliminate the radiation and allow it to be scaled to higher frequencies. Simulation results for 220–330 GHz and 330–500 GHz are obtained, and the transition has an insertion loss of better than 0.5 and 1.2 dB, respectively. The transition is fabricated and characterized at 220–330 GHz, with an insertion loss of better than 0.7 dB and a return loss in excess of 10 dB over the whole band.

  • 22.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    A Very Low Loss 220–325 GHz Silicon Micromachined Waveguide Technology2018In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 8, no 2, p. 248-250Article in journal (Refereed)
    Abstract [en]

    This letter reports for the first time on a very low loss silicon micromachined waveguide technology, implemented for the frequency band of 220–325 GHz. The waveguide is realized by utilizing a double H-plane split in a three-wafer stack. This ensures very low surface roughness, in particular on the top and bottom surfaces of the waveguide, without the use of any surface roughness reduction processing steps. This is superior to previous micromachined waveguide concepts, including E-plane and single H-plane split waveguides. The measured average surface roughness is 2.14 nm for the top/bottom of the waveguide, and 163.13 nm for the waveguide sidewalls. The measured insertion loss per unit length is 0.02–0.07 dB/mm for 220–325 GHz, with a gold layer thickness of 1 μm on the top/bottom and 0.3 μm on the sidewalls. This represents, in this frequency band, the lowest loss for any silicon micromachined waveguide published to date and is of the same order as the best metal waveguides.

    Download full text (pdf)
    fulltext
  • 23.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    Integrated Micromachined Waveguide Absorbers at 220 – 325 GHz2017In: Proceedings of the 47th European Microwave Conference, Nuremberg, October 8-13, 2017, 2017, p. 695-698Conference paper (Refereed)
    Abstract [en]

    This paper presents the characterization of integrated micromachined waveguide absorbers in the frequency band of 220 to 325 GHz. Tapered absorber wedges were cut out of four different commercially available semi-rigid absorber ma terials and inserted in a backshorted micromachined waveguide cavity for characterization. The absorption properties of these materials are only specified at 10 GHz, and their absorption behavior above 100 GHz was so far unknown. To study the effect of the geometry of the absorber wedges, the return loss of different absorber lengths and tapering angles was investigated. The results show that longer and sharper sloped wedges from the material specified with the lowest dielectric constant, but not the highest specified absorption, are superior over other geometries and absorber materials. The best results were achieved for 5 mm long absorbers with a tapering angle of 23° in the material RS-4200 from the supplier Resin Systems, having a return loss of better than 13 dB over the whole frequency range of 220 to 325 GHz. These absorber wedges are intended to be used as matched loads in micromachined waveguide circuits. To the best of our knowledge, this is the first publication characterizing such micromachined waveguide absorbers.

    Download full text (pdf)
    fulltext
  • 24.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Campion, James
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Low-Loss Silicon Micromachined Waveguides Above 100 GHz Utilising Multiple H-plane Splits2018In: Proceedings of the 48th European Microwave Conference, Madrid, October 1-3, 2018, Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1041-1044, article id 8541605Conference paper (Refereed)
    Abstract [en]

    For sub-millimeter and millimeter wave applications rectangular waveguides are an ideal transmission medium. Compared to conventional, metal-milled rectangular waveguides, silicon micromachined waveguides offer a number of advantages. In this paper we present a low-loss silicon micromachined waveguide technology based on a double H-plane split for the frequency bands of 110 – 170 GHz and 220 – 330 GHz. For the upper band a reduced height waveguide is presented, which achieves a loss per unit length of 0.02 – 0.10 dB/mm. This technology has been further adapted to implement a full height waveguide for the lower frequency band of 110 – 170 GHz. The full height waveguide takes advantage of the benefits of the double H-plane split technique to overcome the challenges of fabricating micromachined waveguides at lower frequencies. With measured insertion loss of 0.007 – 0.013 dB/mm, averaging 0.009 dB/mm over the whole band, this technology offers the lowest insertion loss of any D-band waveguide to date. The unloaded Q factor of the D-band waveguide technology is estimated to be in excess of 1600, while a value of 750 has been measured for the reduced height upper band waveguide.

    Download full text (pdf)
    fulltext
  • 25.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Micromachined Waveguides with Integrated Silicon Absorbers and Attenuators at 220–325 GHz2018In: IEEE MTT-S International Microwave Symposium, IEEE conference proceedings, 2018 / [ed] IEEE, IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    This paper reports for the first time on micromachined waveguides with integrated micromachined silicon absorbers. In contrast to epoxy-based microwave absorbers, micromachined lossy silicon absorbers are fully compatible with high temperature fabrication and assembly processes for micromachined waveguides. Furthermore, micromachining enables the fabrication of exact, near ideal taper tips for the silicon absorbers, whereas the tip of epoxy-based absorbers cannot be shaped accurately and reproducibly for small waveguides. Silicon of different conductivity is a very well understood and characterized dielectric material, in contrast to conventional absorber materials which are not specified above 60 GHz. Micromachined silicon waveguides with integrated absorbers and attenuators were designed, fabricated and characterized in the frequency band of 220 – 325 GHz. The return and insertion loss for various taper-geometry variations of double-tip tapered absorbers and attenuators was studied. The average return loss for the best investigated device is 19 dB over the whole band. The insertion loss of the two-port attenuators is 16 – 33 dB for different designs and shows an excellent agreement to the simulated results. The best measured devices of the one-port absorbers exhibit an average and worst-case return loss of 22 dB and 14 dB, respectively, over the whole band. The return loss is not characterized by a good simulation-measurement match, which is most likely attributed to placement tolerances of the absorbers in the waveguide cavities affecting the return but not the insertion loss.

    Download full text (pdf)
    fulltext
  • 26.
    Beuerle, Bernhard
    et al.
    TeraSi AB, Stockholm, Sweden.
    Svedin, Jan
    Swedish Defense Research Agency, FOI, Linköping, Sweden.
    Malmqvist, Robert
    Swedish Defense Research Agency, FOI, Linköping, Sweden.
    Vassilev, Vessen
    Microwave Electronics Laboratory, Chalmers University of Technology, Gothenburg, Sweden.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Zirath, Herbert
    Microwave Electronics Laboratory, Chalmers University of Technology, Gothenburg, Sweden.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Integrating InP MMICs and Silicon Micromachined Waveguides for Sub-THz Systems2023In: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 44, no 10, p. 1800-1803Article in journal (Refereed)
    Abstract [en]

    A novel co-designed transition from InP monolithic microwave integrated circuits to silicon micromachined waveguides is presented. The transition couples a microstrip line to a substrate waveguide sitting on top of a vertical waveguide. The silicon part of the transition consists of a top and a bottom chip, fabricated in a very low-loss silicon micromachined waveguide technology using silicon on insulator wafers. The transition has been designed, fabricated and characterized for 220 GHz to 330 GHz in a back-to-back configuration. Measured insertion loss is 3 dB to 6 dB at 250 GHz to 300 GHz , and return loss is in excess of 5 dB.

    Download full text (pdf)
    fulltext
  • 27.
    Beuerle, Bernhard
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Svedin, Jan
    FOI.
    Robert, Malmqvist
    FOI.
    Vassilev, Vessen
    Chalmers University.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ziraht, Herbert
    Chalmers University.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Integrating InP MMICs and Silicon Micromachined Waveguides for sub-THz SystemsManuscript (preprint) (Other academic)
    Abstract [en]

    A novel co-designed transition from InP monolithic microwave integrated circuits to silicon micromachined waveguides is presented. The transition couples a microstrip line to a substrate waveguide sitting on top of a vertical waveguide. The silicon part of the transition consists of a top and a bottom chip, fabricated in a very low-loss silicon micromachined waveguide technology using silicon on insulator wafers. The transition has been designed, fabricated and characterized for 220–330 GHz in a back-to-back configuration. Measured insertion loss is 3–6 dB at 250–300 GHz, and return loss is in excess of 5 dB.

  • 28. Bhattacharyya, Debabrata
    et al.
    Wright, Rob V.
    Zhang, Q.
    Kirby, Paul B.
    Guerre, Roland
    Drechsler, U.
    Despont, Michel
    Saharil, Farizah
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Material aspects for batch integration of PZT thin films using transfer bonding technologies: Q2M development2008In: Proc. 4M 2008 Conference on Multi-Material Micro Manufacture, 2008Conference paper (Other academic)
    Abstract [en]

    Transfer bonding is a reliable cost-efficient and low-temperature CMOS compatible technique which allows batchintegration of materials whose incompatibility with Si makes them unsuitable for monolithic integration. In thisheterogeneous device integration method the material and process incompatibilities inherent in Si IC technology areovercome by fabricating devices on separate substrates and then transferring them onto target (e.g. CMOS) wafers.Transfer bonding has great potential for integrating RF-MEMS devices incorporating, for example, high thermal budgetmaterials such as PZT and PST or non-ferroelectric piezoelectrics such as AlN and ZnO into microwave ICs forenhanced systems performance. This paper presents an overview of technology developments within the EUsponsored project Q2M for the realization of transfer bonded piezoelectrically actuated RF MEMS switches and othercomponents focusing in particular on material factors relating to growth of the piezoelectric films, in this case sol-geldeposited PZT, that restricts the choice of device layers and impact on PZT properties such as microstructure, filmorientation and piezoelectric coefficients. New process developments such as hard masking of PZT pattern during RIEetching and its compatibility with polymer transfer bonding are discussed.

  • 29.
    Bleiker, Simon J.
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Fischer, Andreas C.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Somjit, Nutapong
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    High-Aspect-Ratio Through Silicon Vias for High-Frequency Application Fabricated by Magnetic Assembly of Gold-Coated Nickel Wires2015In: IEEE Transactions on Components, Packaging, and Manufacturing Technology, ISSN 2156-3950, E-ISSN 2156-3985, Vol. 5, no 1, p. 21-27Article in journal (Refereed)
    Abstract [en]

    In this paper, we demonstrate a novel manufacturing technology for high-aspect-ratio vertical interconnects for high-frequency applications. This novel approach is based on magnetic self-assembly of prefabricated nickel wires that are subsequently insulated with a thermosetting polymer. The high-frequency performance of the through silicon vias (TSVs) is enhanced by depositing a gold layer on the outer surface of the nickel wires and by reducing capacitive parasitics through a low-k polymer liner. As compared with conventional TSV designs, this novel concept offers a more compact design and a simpler, potentially more cost-effective manufacturing process. Moreover, this fabrication concept is very versatile and adaptable to many different applications, such as interposer, micro electromechanical systems, or millimeter wave applications. For evaluation purposes, coplanar waveguides with incorporated TSV interconnections were fabricated and characterized. The experimental results reveal a high bandwidth from dc to 86 GHz and an insertion loss of <0.53 dB per single TSV interconnection for frequencies up to 75 GHz.

    Download full text (pdf)
    fulltext
  • 30.
    Boonlom, Kamol
    et al.
    Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England..
    Chomtong, Pongsathorn
    King Mongkuts Univ Technol North Bangkok, Fac Tech Educ, Dept Teacher Training Elect Engn, Bangkok 10800, Thailand..
    Zhang, Weijia
    Shaoxing Univ, Dept Math, Shaoxing 312000, Peoples R China.;Shaoxing Univ, Inst Artificial Intelligence, Shaoxing 312000, Peoples R China.;Key Lab Artificial Intelligence Multidimens Applic, Shaoxing 312000, Peoples R China.;Univ Oxford, Dept Atmospher Ocean & Planetary Phys, Oxford OX1 4BH, Oxon, England..
    Amsdon, Timothy J.
    Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England..
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. Key Lab Artificial Intelligence Multidimens Applic, Shaoxing 312000, Peoples R China..
    Robertson, Ian D.
    Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England..
    Somjit, Nutapong
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. Univ Leeds, Sch Elect & Elect Engn, Leeds LS2 9JT, England.;Shaoxing Univ, Dept Math, Shaoxing 312000, Peoples R China.
    Advanced Studies on Optical Wireless Communications for in-Pipe Environments: Bandwidth Exploration and Thermal Management2024In: IEEE Access, E-ISSN 2169-3536, Vol. 12, p. 80607-80632Article in journal (Refereed)
    Abstract [en]

    This study presents insights into high-speed optical wireless communication (OWC) within plastic pipes, introducing a Gbps-capable alternative for challenging environments. Utilizing a 1W LED with five wavelengths, the experiment explores signal power, attenuation, and bandwidth characteristics. Notably, the blue LED achieves an unprecedented 58.64 MHz bandwidth, red and purple LEDs demonstrate novel bandwidths of approximately 25.23 MHz, and green and yellow LEDs exhibit unique bandwidths of 23.75 MHz and 9.62 MHz, respectively. The attenuation parameters for different wavelengths provide numerous insights, showcasing the novelty of this research and its potential applications in robot communication within plastic pipes. Concurrently, the paper introduces an approach to address the temperature impact on five distinct wavelength LEDs in OWC. By focusing on variations in LED bandwidth and optical power, an optimal heat sink design is proposed. This design achieves a remarkable minimum temperature of 27.06 degrees C and reduces the chip LED device's response time from 15 to 9 seconds. The significance lies in the novelty of the proposed heat sink, which incorporates variables such as fin thickness, height, air gap width, number of fins, and airflow rate, marking a substantial advancement in thermal management for OWC systems.

  • 31.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    MEMS crossbar switches for telecommunication networks2008Conference paper (Other academic)
  • 32.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    MEMS single-chip 5x5 and 20x20 double-switch arrays for telecommunication networks2007In: IEEE 20th International Conference on Micro Electro Mechanical Systems, 2007. MEMS, New York: IEEE , 2007, p. 811-814Conference paper (Refereed)
    Abstract [en]

    This paper reports on a microelectromechanical switch array with up to 20x20 double switches and packaged on a single chip and utilized for main distribution frames in copper-wire networks. The device includes 5x5 or 20x20 allowing for an any-to-any interconnection of the input line to the specific output line. The switches are on an electrostatic S-shaped film actuator with the contact moving between a top and a bottom electrode. device is fabricated in two parts and is designed to assembled using selective adhesive wafer bonding in a wafer-scale package of the switch array. The 5x5 switch arrays have a size of 6.7x6.4mm(2) and the arrays are 14x10 mm(2) large. The switch actuation for closing/opening the switches averaged over an array measured to be 21.2 V / 15.3 V for the 5x5 array 93.2 V / 37.3 V for the 20x20 array. The total impedance varies on the 5x5 array between 0.126 Omega 0.564 Omega at a measurement current of 1 mA. The resistance of the switch contacts within the 5x5 array determined to be 0.216 Omega with a standard deviation 0. 155 Omega.

  • 33.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    MEMS single-chip microswitch array for re-configuration of telecommunication networks2006In: 2006 European Microwave Conference: Vols 1-4, New York: IEEE , 2006, p. 315-318Conference paper (Refereed)
    Abstract [en]

    This paper reports on a micro-electromechanical (MEMS) switch array embedded and packaged on a single chip. The switch array is utilized for the automated re-configuration of the physical layer of copper-wire telecommunication networks. A total of 25 individually controllable double-switches are arranged in a 6.7 x 6.4 mm(2) large 5x5 switch matrix allowing for any configuration of independently connecting the line-pairs of the five input channels to any line-pair of the five output channels. The metal-contact switch array is embedded in a single chip package, together with 4 metal layers for routing the signal and control lines and with a total of 35 I/O contact pads. The MEMS switches are based on an electrostatic S-shaped thin membrane actuator with the switching contact bar rolling between a top and a bottom electrode. This special switch design allows for low actuation voltage (21.23 V) to close the switches and for high isolation. The total signal line resistances of the routing network vary from 0.57 Omega to 0.98 Omega. The contact resistance of the gold contacts is 0.216 Omega.

  • 34.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Row/column addressing scheme for large electrostatic actuator MEMS switch arrays and optimization of the operational reliability by statistical analysis2008In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 17, no 5, p. 1104-1113Article in journal (Refereed)
    Abstract [en]

    This paper investigates the design and optimization of a row/column addressing scheme to individually pull in or pull out single electrostatic actuators in an N(2) array, utilizing the electromechanical hysteresis behavior of electrostatic actuators and efficiently reducing the number of necessary control lines from N(2) complexity to 2N. This paper illustrates the principle of the row/column addressing scheme. Furthermore, it investigates the optimal addressing voltages to individually pull in or pull out single actuators with maximum operational reliability, determined by the statistical parameters of the pull-in and pull-out characteristics of the actuators. The investigated addressing scheme is implemented for the individual addressing of cross-connect switches in a microelectromechanical systems 20 x 20 switch array, which is utilized for the automated any-to-any interconnection of 20 input signal line pairs to 20 output signal line pairs. The investigated addressing scheme and the presented calculations were successfully tested on electrostatic actuators in a fabricated 20 x 20 array. The actuation voltages and their statistical variations were characterized for different subarray cluster sizes. Finally, the addressing voltages were calculated and verified by tests, resulting in an operational reliability of 99.9498% (502 parts per million (ppm) failure rate) for a 20 x 20 switch array and of 99.99982% (1.75 ppm failure rate) for a 3 x 3 subarray cluster. The array operates by ac-actuation voltage to minimize the disturbing effects by dielectric charging of the actuator isolation layers, as observed in this paper for dc-actuation voltages.

  • 35.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Single-chip MEMS 5x5 and 20x20 double-pole single-throw switch arrays for automating telecommunication networks2008In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 18, no 1, p. 015014-Article in journal (Refereed)
    Abstract [en]

    This paper reports on microelectromechanical (MEMS) switch arrays with 5 × 5 and 20 × 20 double-pole single-throw (DPST) switches embedded and packaged on a single chip, which are intended for automating main distribution frames in copper-wire telecommunication networks. Whenever a customer requests a change in his telecommunication services, the copper-wire network has to be reconfigured which is currently done manually by a costly physical re-routing of the connections in the main distribution frames. To reduce the costs, new methods for automating the network reconfiguration are sought after by the network providers. The presented devices comprise 5 × 5 or 20 × 20 double switches, which allow us to interconnect any of the 5 or 20 input lines to any of the 5 or 20 output lines. The switches are based on an electrostatic S-shaped film actuator with the switch contact on a flexible membrane, moving between a top and a bottom electrode. The devices are fabricated in two parts which are designed to be assembled using selective adhesive wafer bonding, resulting in a wafer-scale package of the switch array. The on-chip routing network consists of thick metal lines for low resistance and is embedded in bencocyclobutene (BCB) polymer layers. The packaged 5 × 5 switch arrays have a size of 6.7 × 6.4 mm2 and the 20 × 20 arrays are 14 × 10 mm2 large. The switch actuation voltages for closing/opening the switches averaged over an array were measured to be 21.2 V/15.3 V for the 5 × 5 array and 93.2 V/37.3 V for the 20 × 20 array, respectively. The total signal line resistances vary depending on the switch position within the array between 0.13 Ω and 0.56 Ω for the 5 × 5 array and between 0.08 Ω to 2.33 Ω for the 20 × 20 array, respectively. The average resistance of the switch contacts was determined to be 0.22 Ω with a standard deviation of 0.05 Ω.

  • 36.
    Braun, Stefan
    et al.
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Smart individual switch addressing of 5×5 and 20×20 MEMS double-switch arrays2007In: TRANSDUCERS and EUROSENSORS '07 - 4th International Conference on Solid-State Sensors, Actuators and Microsystems, IEEE , 2007, p. 153-156Conference paper (Other academic)
    Abstract [en]

    This paper presents a smart row / column addressing scheme for large MEMS rnicroswitch arrays, utilizing the pull-in / pull-out hysteresis of their electrostatic actuators to efficiently reduce the number of control lines. Single-chip 20 x 20 double-switch switch arrays with individually programmable 400 switch elements have been fabricated and the smart addressing scheme was successfully evaluated. The reproducibility of the actuation voltages within the array is very important for this addressing scheme and therefore the influence of effects such as isolation layer charging on the pull-in voltages has also been investigated.

  • 37.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Beuerle, Bernhard
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Krivovitca, Aleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Low-Loss Hollow and Silicon-Core Micromachined Waveguide Technologies Above 100 GHz2018Conference paper (Other academic)
  • 38.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Glubokov, Oleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gomez-Torrent, Adrian
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Krivovitca, Aleksandr
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Bolander, Lars
    Ericsson Research.
    Li, Yinggang
    Ericsson Research.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    An Ultra Low-Loss Silicon-Micromachined Waveguide Filter for D-Band Telecommunication Applications2018In: 2018 IEEE/MTT-S International Microwave Symposium, IEEE, 2018, p. 583-586Conference paper (Refereed)
    Abstract [en]

    A very low-loss micromachined waveguide bandpassfilter for use in D-band (110–170GHz) telecommunication applicationsis presented. The 134–146GHz filter is implemented in a silicon micromachined technology which utilises a double H-plane split, resulting in significantly lower insertion loss than conventional micromachined waveguide devices. Custom split-blocks are designed and implemented to interface with the micromachined component. Compact micromachined E-plane bends connect the split-blocks and DUT. The measured insertion loss per unit length of the waveguide technology (0.008–0.016 dB/mm) is the lowest reported to date for any micromachined waveguide at D-band. The fabricated 6-pole filter, with a bandwidth of 11.8 GHz (8.4%), has a minimum insertion loss of 0.41 dB, averaging 0.5 dB across its 1 dB bandwidth, making it the lowest-loss D-band filter reported to date in any technology. Its return loss is better than 20 dB across 85% of the same bandwidth. The unloaded quality factor of a single cavity resonator implemented in this technology is estimated to be 1600.

    Download full text (pdf)
    fulltext
  • 39.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Hassona, A.
    He, Z. S.
    Beuerle, Bernhard
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Gomez-Torrent, Adrian
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Vecchiattini, S.
    Lindman, R.
    Dahl, T. S.
    Li, Y.
    Zirath, H.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Toward Industrial Exploitation of THz Frequencies: Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems2019In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 9, no 6, p. 624-636Article in journal (Refereed)
    Abstract [en]

    A new integration concept for terahertz (THz) systems is presented in this article, wherein patterned silicon-on-insulator wafers form all DC, IF, and RF networks in a homogeneous medium, in contrast to existing solutions. Using this concept, silicon-micromachined waveguides are combined with silicon germanium (SiGe) monolithic microwave integrated circuits (MMICs) for the first time. All features of the integration platform lie in the waveguide’s H-plane. Heterogeneous integration of SiGe chips is achieved using a novel in-line H-plane transition. As an initial step toward complete systems, we outline the design, fabrication, and assembly of back-to-back transition structures, for use at D-band frequencies (110ï¿œ170 GHz). Special focus is given to the industrial compatibility of all components, fabrication, and assembly processes, with an eye on the future commercialization of THz systems. Prototype devices are assembled via two distinct processes, one of which utilizes semiautomated die-bonding tools. Positional and orientation tolerances for each process are quantified. An accuracy of $\pm \text3.5\; μ \textm$, $\pm \text1.5 °$ is achieved. Measured $S$-parameters for each device are presented. The insertion loss of a single-ended transition, largely due to MMIC substrate losses, is 4.2ï¿œ5.5 dB, with a bandwidth of 25 GHz (135ï¿œ160 GHz). Return loss is in excess of 5 dB. Measurements confirm the excellent repeatability of the fabrication and assembly processes and, thus, their suitability for use in high-volume applications. The proposed integration concept is highly scalable, permitting its usage far into the THz frequency spectrum. This article represents the first stage in the shift to highly compact, low-cost, volume-manufacturable THz waveguide systems.

    Download full text (pdf)
    fulltext
  • 40.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Silicon Micromachined Waveguide Calibration Standards for Terahertz MetrologyManuscript (preprint) (Other academic)
    Abstract [en]

    We present silicon micromachined waveguide calibration standards for use with terahertz vector network analysers. We show how a single silicon-on-insulator wafer with correctly chosen device and handle layer thicknesses can be used to implement a wide range of calibration standards without the need for assembly of multiple components. The design of thestandards is reviewed from mechanical, electrical and end-userperspectives. By solid mechanics analysis we outline the potential to scale the presented design to at least 2.6 THz. In addition, a review of typical waveguide materials is performed to assess their compatibility with our design. It is found that silicon is by far the most promising material for the realisation of calibration standards. A total of eight types of standard are realised. The RF performance of 15 prototypes is characterised between 325 –500 GHz. Despite some fabrication anomalies all prototype standards show good agreement with theoretical models. Measured S-parameters of the standards are utilised to implement both one-and two-port calibrations, including the highly accurate multiline through-reflect-line algorithm. These are benchmarked against calibrations performed using conventional metallic standards,with favourable results. This work enables the creation of low-cost, highly-repeatable and traceable waveguide calibration standards for terahertz frequencies, surpassing the limits of current metrology techniques.

  • 41.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Silicon Micromachined Waveguide Calibration Standards for Terahertz Metrology2021In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 69, no 8, p. 3927-3942Article in journal (Refereed)
    Abstract [en]

    This article presents precision silicon micromachined waveguide calibration standards for use with terahertz vector network analyzers. This enables the creation of precise, highly repeatable, and traceable terahertz waveguide standards, surpassing the limits of current metrology techniques. A single silicon-on-insulator wafer with the appropriate device and handle layer thicknesses is used to implement a wide range of calibration and verification standards. The design of the standards is discussed from mechanical, electrical, and end-user perspectives. Silicon is shown to be the most promising material for the realization of precision metrology standards. We outline the potential to scale the presented design to at least 2.6 THz. Eight types of WM-570 standard, totaling 15 prototypes, are fabricated and characterized between 325 and 500 GHz. Despite some fabrication anomalies, all devices offer excellent performance. The best micromachined standards offer a return loss in excess of 40 dB, an insertion loss of below 0.1 dB, and a phase error of less than 1 degrees. The standards are utilized in both one- and two-port calibrations, including the multiline through-reflect-line algorithm. These are benchmarked against calibrations performed using conventional metallic standards, with a high degree of agreement observed between error-corrected measurements of a range of test devices.

  • 42.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Traceability of Silicon Micromachined Waveguide Calibration Standards from 325 - 500 GHzManuscript (preprint) (Other academic)
    Abstract [en]

    This paper reports initial progress towards establishing metrological traceability of a new class of silicon micromachined waveguide calibration standards for use in terahertz metrology. The accuracy and precision of our micromachined standards exceeds that of current state-of-the-art calibration standards, making them highly promising for use in precision terahertz waveguide measurement and calibration. Establishing traceability requires that the cross-sectional dimensions of a waveguide standard, and the uncertainty in its electrical performance, be accurately quantified. To achieve this, dimensional characterisation of a micromachined standard is performed using white-light interferometry. The waveguide aperture is accurate to within 0.1 μm and 1.7 μm along its width and height. A detailed Monte Carlo analysis is performed to investigate the uncertainty and error levels caused by a total of 9 different sources of uncertainty. These include all fabrication related uncertainties, as well as those arising from misalignment of waveguides in experimental scenarios. The effect of each of these tolerances is investigated both independently and cumulatively, allowing their importance to be determined. Bounds on the simulated magnitude and phase uncertainties of the calibration standards, along with expected values, are derived. These are then compared to experimental uncertainty calculated from the measurementof 15 prototype calibration standards of 3 different lengths. An average uncertainty as low as 0.0009 is observed in the magnitude of reflective and transmissive measurements, with average transmissive phase uncertainty of 1.25◦ .

  • 43.
    Campion, James
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Elliptical alignment holes enabling accurate direct assembly of micro-chips to standard waveguide flanges at sub-THz frequencies2017In: 2017 IEEE MTT-S International Microwave Symposium (IMS), Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1262-1265, article id 8058838Conference paper (Refereed)
    Abstract [en]

    Current waveguide flange standards do not allow for the accurate fitting of microchips, due to the large mechanical tolerances of the flange alignment pins and the brittle nature of Silicon, requiring greatly oversized alignment holes on the chip to fit worst-case fabrication tolerances, resulting in unacceptably large misalignment error for sub-THz frequencies. This paper presents, for the first time, a new method for directly aligning micromachined Silicon chips to standard, i.e. unmodified, waveguide flanges with alignment accuracy significantly better than the waveguide-flange fabrication tolerances, through the combination of a tightly-fitting circular and an elliptical alignment hole on the chip. A Monte Carlo analysis predicts the reduction of the mechanical assembly margin by a factor of 5.5 compared to conventional circular holes, reducing the potential chip misalignment from 46 μm to 8.5 μm for a probability of fitting of 99.5%. For experimental verification, micromachined waveguide chips using either conventional (oversized) circular or the proposed elliptical alignment holes were fabricated and measured. A reduction in the standard deviation of the reflection coefficient by a factor of up to 20 was experimentally observed from a total of 200 measurements with random chip placement, exceeding the expectations from the Monte Carlo analysis. To our knowledge, this paper presents the first solution for highly accurate assembly of micromachined waveguide chips to standard waveguide flanges, requiring no custom flanges or other tailor-made split blocks.

    Download full text (pdf)
    fulltext
  • 44.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Repeatability of Silicon Micromachined Waveguide Components Connected to Metallic Waveguide Flanges at 220 - 330 GHzManuscript (preprint) (Other academic)
    Abstract [en]

    This paper investigates the repeatability of silicon micromachined waveguide components which are connected to metallic waveguide flanges and the impact of misalignment on it. Quantifying the repeatability of such components is essential to enable their use in high-volume applications, where randomd evice performance variations must be avoided. Misalignment is a significant contributor to experimental uncertainty andlimits the achievable return loss between a pair of waveguides. Misalignment is not the only factor which affects repeatability - variations in clamping pressure and mechanical wear to the various components also have an influence. These effects are not well understood as they are difficult to quantify, model or simulate. Here, we apply the elliptical alignment holes concept to greatly reduced the potential misalignment between siliconmicromachined chips and metallic flanges without the need to oversize the chip’s alignment holes. We design and fabricaten umerous samples which allow varying levels of misalignment and characterise them in a 2-port measurement setup from 220 –330 GHz. Mechanical wear of the micromachined components is examined and compared to the experimental results. The elliptical alignment hole concept is found to reduce experimentaluncertainty in |S11 | and |S21 | by up to a factor of 1.7 and 1.25, respectively, without reducing the probability of the chip fitting on the metallic flange.

  • 45.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Shah, Umer
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Silicon-Micromachined Waveguide Calibration Shims for Terahertz Frequencies2019In: Proceedings 2019 IEEE MTT-S International Microwave Symposium (IMS), IEEE, 2019Conference paper (Refereed)
    Abstract [en]

    A new method of realising precision waveguide shims for use in THz Through-Reflect-Line (TRL) calibrations, based on silicon-micromachining, is introduced. The proposed calibration shims combine a thin λ/4 silicon layer, co-fabricated with a thicker layer which provides mechanical support. This design overcomes the limitations of CNC milling for the creation of calibration shims, facilitating use of standard TRL calibration at currently challenging frequencies. The novel shim fits inside the inner recess of a standard waveguide flange and is compatible with conventional flange alignment pins. Five micromachined shims were fabricated in a silicon-on-insulator process for operation in the WM-570 waveguide band (325–500GHz). The fabricated shims show excellent performance across the entire band, with return loss in excess of 25dB, insertion loss below 0.2 dB and high uniformity between samples. Verification reveals that the micromachined shims have an electrical length within 2% of the expected value. Comparative measurements of a DUT calibrated with the proposed shim and a previously un-used conventional metallic shim show that the novel concept offers equivalent, if not better, performance. The mechanical design of the micromachined shim and the rigid nature of silicon ensure that it will not suffer from performance degradation with repeated use, as is problematic with thin metallic shims. This work enables the creation of low-cost, highly-repeatable, traceable calibration shims with micrometer feature-sizes and high product uniformity, surpassing the limits of current techniques.

    Download full text (pdf)
    fulltext
  • 46.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Xenidis, Nikolaos
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ivanov, Roman
    Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Estonia.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Hussainova, Irina
    Department of Mechanical and Industrial Engineering, Tallinn University of Technology, Estonia.
    Lioubtchenko, Dmitri
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. CENTERA Laboratories, Institute of High-Pressure Physics, PAS, Warsaw, Poland.
    Ultra-wideband waveguide embedded graphene-based THz absorber2021In: The 11th International Conference on Metamaterials, Photonic Crystals and Plasmonics, META 2021, META Conference , 2021, p. 926-927Conference paper (Refereed)
    Abstract [en]

    A novel type of absorber material integrated in a standard metal waveguide is developed for the ultra-wide frequency range of 67-500 GHz. The absorber is based on graphene augmented inorganic nanofibers which are deposited inside a metallic waveguide cassette, allowing them to be utilised in standard waveguide systems. The material’s microstructures result in a low level of reflectance (< -15 dB) and good absorbance (> 20 dB) from 110-500 GHz due to the porosity of the sample and attenuation caused by graphene, making them highly suited for wideband terahertz applications.

  • 47.
    Campion, James
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. TeraSi AB Stockholm 139 33 Sweden.
    Xenidis, Nikolaos
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Smirnov, Serguei
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems.
    Ivanov, Roman
    Tallinn University of Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. Department of Mechanical and Electrical Engineering Tallinn University of Technology Tallinn 19086 Estonia.
    Hussainova, Irina
    Tallinn University of Technology.
    Lioubtchenko, Dmitri
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Micro and Nanosystems. CENTERA Laboratories Institute of High‐Pressure Physics PAS Warsaw 01‐142 Poland.
    Ultra‐Wideband Integrated Graphene‐Based Absorbers for Terahertz Waveguide Systems2022In: Advanced Electronic Materials, E-ISSN 2199-160X, Vol. 8, no 9, p. 2200106-2200106Article in journal (Refereed)
    Abstract [en]

    This article presents novel graphene-based absorber materials which can be directly integrated in terahertz waveguide systems. A simple, low-cost integration method is developed, allowing graphene augmented inorganic nanofibers to be embedded inside a metallic waveguide. In contrast to existing absorbers, the ability to embed such materials in a metallic waveguide allows them to be integrated into complete terahertz systems for large-scale applications. The electromagnetic properties of such materials are then examined using standard network analysis techniques. A wideband measurement setup is developed to enable measurement of a single sample from 67 to 500 GHz, eliminating the need to fabricate multiple samples. The porosity of the integrated material leads to excellent electromagnetic performance across a wide range of frequencies. The samples are found to have a reflection coefficient less than −10 dB for frequencies above200 GHz, while their attenuation per unit length exceeds 35 dB mm−1. The low reflectivity of the material allows it to be used in systems applications where undesired reflections must be avoided. The electromagnetic shielding effectiveness of the material is assessed, with a total effectiveness of 20–45 dB observed for 0.84 mm thick samples.

    Download full text (pdf)
    fulltext
  • 48. Chicherin, Dmitry
    et al.
    Dudorov, Sergey
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Raisanen, Antti V.
    Micro-fabricated High-impedance Surface for Millimeter Wave Beam Steering Applications2008In: 33RD INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES: VOLS 1 AND 2, NEW YORK: IEEE , 2008, p. 574-576Conference paper (Refereed)
    Abstract [en]

    A multi-layer high-impedance surface has been micro-fabricated and measured in W band. It consists of an array of capacitors placed on a dielectric substrate with a ground plane. Reconfigurability of the effective surface impedance of this structure can be enabled by applying control voltage to the tunable capacitors. Tunable impedance surfaces can be used in phase shifters for a phased array antenna, and directly as a smart beam steering surface.

  • 49.
    Chicherin, Dmitry
    et al.
    Department of Radio Science and Engineering, SMARAD Centre of Excellence, Aalto University.
    Dudorov, Sergey
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Räisänen, Antti V.
    Department of Radio Science and Engineering, SMARAD Centre of Excellence, Aalto University.
    Rectangular metal waveguide phase shifter controlled with MEMS high-impedance surface2008In: Proc. of the XXXI Finnish URSI Convention on Radio Science Electromagnetics 2008, 2008Conference paper (Refereed)
  • 50.
    Chicherin, Dmitry
    et al.
    Department of Radio Science and Engineering, SMARAD Centre of Excellence, Aalto University.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Baghchehsaraei, Zargham
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Dudorov, Sergey
    KTH, School of Electrical Engineering (EES), Microsystem Technology.
    Du, Z.
    Zvolensky, T.
    Vorobyov, A.
    Gago, M. de Miguel
    Fourn, E.
    Sauleau, Ronan
    Labia, Thierry
    Shhade, G. El Haj
    Bodereau, F.
    Mallejac, P.
    Åberg, Jan
    Simovski, C.
    Räisänen, Antti V.
    MEMS tunable metamaterials for beam steering millimeter wave applications2009In: NATO-Advanced Research Workshop: Advanced Materials and Technologies for Micro/Nano Devices, Sensors and Actuators, 2009Conference paper (Other academic)
123456 1 - 50 of 276
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf