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Oberhammer, Joachim, ProfessorORCID iD iconorcid.org/0000-0003-3339-9137
Publications (10 of 40) Show all publications
Smirnov, S., Morales, A., Okonkwo, C., Tafur Monroy, I., Lioubtchenko, D. & Oberhammer, J. (2019). Dielectric Rod Antenna Array for Photonic-Based Sub-Terahertz Beamforming. In: : . Paper presented at 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Maison de la Chimie, Paris; France; 1-6 September 2019. IEEE
Open this publication in new window or tab >>Dielectric Rod Antenna Array for Photonic-Based Sub-Terahertz Beamforming
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2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This work presents a dielectric rod antenna array designed for a photonic-enabled beamforming system at subterahertz frequencies. The photonic chip generates an optical group delay, providing the beam-steering capability. The antenna array is fabricated from high-resistivity silicon by micromachining. Simulation results demonstrate a directivity of 14.7 dBi and a beam steering range of 56 degrees at 85 GHz. The system is intended as a sub-THz transmitter for broadband wireless communications.

Place, publisher, year, edition, pages
IEEE, 2019
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-264577 (URN)10.1109/IRMMW-THz.2019.8874432 (DOI)2-s2.0-85074715467 (Scopus ID)978-1-5386-8285-2 (ISBN)
Conference
44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz), Maison de la Chimie, Paris; France; 1-6 September 2019
Funder
EU, Horizon 2020, 675683EU, Horizon 2020, 616846
Note

QC 20191202

Available from: 2019-11-29 Created: 2019-11-29 Last updated: 2019-12-03Bibliographically approved
Glubokov, O., Xinghai, Z., Campion, J., Beuerle, B., Shah, U. & Oberhammer, J. (2019). Investigation of Fabrication Accuracy and Repeatability of High-Q Silicon-Micromachined Narrowband Sub-THz Waveguide Filters. IEEE transactions on microwave theory and techniques, 67(9), 3696-3706
Open this publication in new window or tab >>Investigation of Fabrication Accuracy and Repeatability of High-Q Silicon-Micromachined Narrowband Sub-THz Waveguide Filters
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2019 (English)In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 67, no 9, p. 3696-3706Article in journal (Refereed) Published
Abstract [en]

This paper investigates the fabrication accuracy and repeatability of micromachined quadruplet filters designed at a center frequency of 270 GHz with a 5-GHz bandwidth using a versatile multilayer chip platform which allows for axially arranged waveguide ports. A large number of narrowband silicon-micromachined filters arranged on multiple chips are investigated for fabrication imperfections, assembly misalignment, and fabrication yield, employing fabrication-prediction and different chip-to-chip self-alignment feature strategies. A numerical technique for characterization of the entire fabrication process of the filters through extracting the error statistics for coupling coefficients of a large number of different samples from separately assembled chips is proposed. A total of 47 test filters in effectively 15 different design variants have been fabricated in two fabrication runs, evaluated, and analyzed. The most critical sources of errors are determined. The expected accuracy of the entire filters fabrication process is demonstrated through the yield analysis based on the collected error statistics.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Coupling matrices, dual-mode filters, microfabrication, micromachining technology, waveguide filters, yield analysis
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-262976 (URN)10.1109/TMTT.2019.2926244 (DOI)000489766500018 ()
Note

QC 20191031

Available from: 2019-10-31 Created: 2019-10-31 Last updated: 2019-10-31Bibliographically approved
Glubokov, O., Xinghai, Z., Campion, J., Shah, U. & Oberhammer, J. (2019). Micromachined Filters at 450 GHz With 1% Fractional Bandwidth and Unloaded Q Beyond 700. IEEE Transactions on Terahertz Science and Technology, 9(1)
Open this publication in new window or tab >>Micromachined Filters at 450 GHz With 1% Fractional Bandwidth and Unloaded Q Beyond 700
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2019 (English)In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 9, no 1Article in journal (Refereed) Published
Abstract [en]

This letter presents two silicon-micromachined narrowband fourth-order waveguide filter concepts with center frequency of 450 GHz, which are the first narrowband submillimeter-wave filters implemented in any technology with a fractional bandwidth as low as 1%. Both filters designs are highly compact and have axial port arrangements, so that they can be mounted directly between two standard waveguide flanges without needing any split-block interposers. The first filter concept contains two TM 110 dual-mode cavities of circular shape with coupling slots and perturbations arranged in two vertically stacked layers, while the second filter concept is composed of four TE 101 series resonators arranged in a folded, two-level topology without crosscouplings. Prototype devices are fabricated in a multilayer chip platform by high-precision, low-surface roughness deep-silicon etching on silicon-on-insulator wafers. The measured passband insertion loss of two prototype devices of the dual-mode circular-cavity filters is 2.3 dB, and 2.6 dB for three prototypes of the folded filter design. The corresponding extracted unloaded quality factors of the resonators are 786 ± 7 and 703 ± 13, respectively, which are the best so far reported for submillimeter-wave filters in any technology. The presented filters are extremely compact in terms of size; their footprints have areas of only 0.53 and 0.55 mm 2 , respectively, and the thickness between the waveguide flanges is 0.9 mm.

Keywords
All-pole filters, dual-mode filters, microfabrication, micromachining technology, waveguide filters
National Category
Telecommunications
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-242575 (URN)10.1109/TTHZ.2018.2883075 (DOI)000455919800012 ()2-s2.0-85057418315 (Scopus ID)
Funder
EU, Horizon 2020, 616846Swedish Foundation for Strategic Research , SE13-007
Note

QC 20190204

Available from: 2019-01-31 Created: 2019-01-31 Last updated: 2019-07-10Bibliographically approved
Morales, A., Smirnov, S., Lioubtchenko, D., Oberhammer, J., Okonkwo, C. & Tafur Monroy, I. (2019). Photonic-Based Beamforming System for Sub-THz Wireless Communications. In: : . Paper presented at 2019 European Microwave Conference in Central Europe (EuMCE), Prague, Czech Republic, May 13-15 2019 (pp. 253-256).
Open this publication in new window or tab >>Photonic-Based Beamforming System for Sub-THz Wireless Communications
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2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This work presents a sub-THz transmitter scheme for wireless communications with beam steering capabilities based on photonics means. A true time delay 1x4 beamforming photonic chip is designed in Si3N4 technology to continuously tune the progressive time delay between consecutive antenna elements. Simulation results show a progressive delay up to 15 ps with a bandwidth of 1.3 GHz, enabling broadband operation at frequencies above 75 GHz. The sub-THz signals are generated on photoconductive antennas on chip by photonic heterodyning. The design of a dielectric rod antenna array is also presented to efficiently radiate the generated wave.

National Category
Telecommunications
Identifiers
urn:nbn:se:kth:diva-262739 (URN)978-2-87487-067-5 (ISBN)978-1-7281-1240-4 (ISBN)
Conference
2019 European Microwave Conference in Central Europe (EuMCE), Prague, Czech Republic, May 13-15 2019
Note

QC 20191107

Available from: 2019-10-20 Created: 2019-10-20 Last updated: 2019-11-07Bibliographically approved
Makhalov, P. B., Lioubtchenko, D. & Oberhammer, J. (2019). Semiconductor-Metal-Grating Slow Wave Amplifier for Sub-THz Frequency Range. IEEE Transactions on Electron Devices, 66(10), 4413-4418
Open this publication in new window or tab >>Semiconductor-Metal-Grating Slow Wave Amplifier for Sub-THz Frequency Range
2019 (English)In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 66, no 10, p. 4413-4418Article in journal (Refereed) Published
Abstract [en]

The concept of semiconductor slow wave amplifier aimed at sub-terahetz frequencies is studied numerically. The scheme of the transversal amplifier with metal grating is proposed. The requirements on semiconductor parameters that provide positive net amplification are given and discussed, and the choice of GaN is explained. For the proposed device, different regimes are studied, and the dependence of the net amplification on device parameters is given. One regime has high linear gain, more than 50 dB/mm. The proof-of-principle structure for the excitation of the device in this regime is proposed and simulated.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Microwave amplifiers, plasmons, semiconductor devices, terahertz (THz) radiation
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-264288 (URN)10.1109/TED.2019.2935312 (DOI)000487477600047 ()
Note

QC 20191203

Available from: 2019-12-03 Created: 2019-12-03 Last updated: 2019-12-03Bibliographically approved
Campion, J., Shah, U. & Oberhammer, J. (2019). Silicon-Micromachined Waveguide Calibration Shims for Terahertz Frequencies. In: : . Paper presented at 2019 IEEE/MTT-S International Microwave Symposium, IMS 2019; Boston; United States; 2 June 2019 through 7 June 2019.
Open this publication in new window or tab >>Silicon-Micromachined Waveguide Calibration Shims for Terahertz Frequencies
2019 (English)Conference paper, Published 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.

National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-256491 (URN)2-s2.0-85069969373 (Scopus ID)
Conference
2019 IEEE/MTT-S International Microwave Symposium, IMS 2019; Boston; United States; 2 June 2019 through 7 June 2019
Funder
Swedish Foundation for Strategic Research , SE13- 007EU, Horizon 2020, 616846
Note

QC 20190903

Available from: 2019-08-26 Created: 2019-08-26 Last updated: 2019-09-03Bibliographically approved
Smirnov, S., Lioubtchenko, D. & Oberhammer, J. (2019). Single-walled carbon nanotube layers for millimeter-wave beam steering. Nanoscale
Open this publication in new window or tab >>Single-walled carbon nanotube layers for millimeter-wave beam steering
2019 (English)In: Nanoscale, ISSN 2040-3364, E-ISSN 2040-3372Article in journal (Refereed) Published
Abstract [en]

The ability to efficiently transmit and manipulate high-frequency signals poses major challenges resulting in a lack of active and reconfigurable millimeter-wave and terahertz devices that are needed to enable beyond-5G broadband communication systems. Here, thin single-walled carbon nanotube (SWCNT) layers are introduced as a tunable impedance surface for millimeter-waves. Carbon nanotube layers are integrated with dielectric rod waveguides. Their surface impedance, tuned by light, is shown to modify the wave propagation inside the waveguide. A direct application of the effect is a phase shifter, demonstrated experimentally and by numerical simulations. Additionally, an antenna array of two dielectric waveguides, one covered in SWCNTs, is designed and fabricated. The proof-of-concept illustrates optically-controlled beam steering enabled by carbon nanotubes, and directions for further device optimizations are provided. These findings demonstrate thin SWCNT layers as an optically-reconfigurable element, suitable for broadband millimeter-wave communications.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-255274 (URN)10.1039/c9nr02705j (DOI)000484297400017 ()2-s2.0-85070838328 (Scopus ID)
Funder
EU, Horizon 2020, 675683EU, Horizon 2020, 616846
Note

QC 20190729

Available from: 2019-07-25 Created: 2019-07-25 Last updated: 2019-10-01Bibliographically approved
Campion, J., Hassona, A., He, Z. S., Beuerle, B., Gomez-Torrent, A., Shah, U., . . . Oberhammer, J. (2019). Toward Industrial Exploitation of THz Frequencies: Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems. IEEE transactions on rehabilitation engineering, 9(6), 624-636
Open this publication in new window or tab >>Toward Industrial Exploitation of THz Frequencies: Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems
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2019 (English)In: IEEE transactions on rehabilitation engineering, ISSN 1063-6528, E-ISSN 1558-0024, Vol. 9, no 6, p. 624-636Article in journal (Refereed) Published
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.

Keywords
Silicon germanium;Waveguide components;Radio frequency;Fabrication;Packaging;Insertion loss;Routing;Integrated circuit packaging;micromachined waveguide;monolithic microwave integrated circuit (MMIC);silicon germanium (SiGe);terahertz (THz)
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-263604 (URN)10.1109/TTHZ.2019.2943572 (DOI)2-s2.0-85074981066 (Scopus ID)
Funder
EU, European Research Council, 644039
Note

QC 20191209

Available from: 2019-12-06 Created: 2019-12-06 Last updated: 2019-12-09Bibliographically approved
Smirnov, S., Anoshkin, I. V., Generalov, A., Lioubtchenko, D. & Oberhammer, J. (2019). Wavelength-dependent photoconductivity of single-walled carbon nanotube layers. RSC Advances, 9(26), 14677-14682
Open this publication in new window or tab >>Wavelength-dependent photoconductivity of single-walled carbon nanotube layers
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2019 (English)In: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 9, no 26, p. 14677-14682Article in journal (Refereed) Published
Abstract [en]

A number of electronic devices such as phase shifters, polarizers, modulators, and power splitters are based on tunable materials. These materials often do not meet all the requirements namely low losses, fast response time, and technological compatibility. Novel nanomaterials, such as single-walled carbon nanotubes, are therefore widely studied to fill this technological gap. Here we show how the dielectric constant of single-walled carbon nanotube layers can be substantially modified by illuminating them due to unique light–matter interactions. We relate the optical excitation of the nanotube layers to the illumination wavelength and intensity, by resistance and capacitance measurements. The dielectric constant is modified under laser illumination due to the change of material polarization and free carrier generation, and is shown to not be temperature-related. The findings indicate that SWCNT layers are a prospective tunable optoelectronic material for both high and low frequency applications.

Place, publisher, year, edition, pages
RSC Publishing, 2019
National Category
Nano Technology
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-251605 (URN)10.1039/C9RA01467E (DOI)000468641300013 ()2-s2.0-85065863568 (Scopus ID)
Funder
EU, Horizon 2020, 675683EU, Horizon 2020, 616846
Note

QC 20190515

Available from: 2019-05-15 Created: 2019-05-15 Last updated: 2019-06-20Bibliographically approved
He, Z. S., Bao, M., Li, Y., Hassona, A., Campion, J., Oberhammer, J. & Zirath, H. (2018). A 140 GHz Transmitter with an Integrated Chip-to-Waveguide Transition using 130nm SiGe BiCMOS Process. In: 2018 ASIA-PACIFIC MICROWAVE CONFERENCE PROCEEDINGS (APMC): . Paper presented at 30th Asia-Pacific Microwave Conference, APMC 2018; Kyoto; Japan; 6 November 2018 through 9 November 2018 (pp. 28-30). IEEE
Open this publication in new window or tab >>A 140 GHz Transmitter with an Integrated Chip-to-Waveguide Transition using 130nm SiGe BiCMOS Process
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2018 (English)In: 2018 ASIA-PACIFIC MICROWAVE CONFERENCE PROCEEDINGS (APMC), IEEE , 2018, p. 28-30Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents a 140 GHz transmitter chipset realized in a 130 nm SiGe BiCMOS technology with f(t)/f(max) values of 250 GHz/ 370 GHz. This design comprises of a frequency sixtupler, a balanced transconductance mixer, an amplifier and chip-to-waveguide transition. The frequency multiplier operates in wide frequency band from 110-147 GHz, while the amplifier operates between 115-155 GHz. The total DC power consumption of the chipset is 420 mW. The chip size is 3 mm x 0.73 mm including chip-to-waveguide transition. The transmitter gives -4 dBm output power at 140 GHz and can operate between 129-148 GHz. Wireless data transmission up to 6 Gbps is measured using PSK and QAM modulation schemes.

Place, publisher, year, edition, pages
IEEE, 2018
Keywords
D-band, transmitter chipset, mixer, SiGe BiCMOS, chip-to-waveguide transition
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Telecommunications
Identifiers
urn:nbn:se:kth:diva-244583 (URN)000457599800010 ()2-s2.0-85061778811 (Scopus ID)
Conference
30th Asia-Pacific Microwave Conference, APMC 2018; Kyoto; Japan; 6 November 2018 through 9 November 2018
Note

QC 20190306

Available from: 2019-03-06 Created: 2019-03-06 Last updated: 2019-03-06Bibliographically approved
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Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-3339-9137

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