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  • 201.
    Pardon, Gaspard
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    From Macro to Nano: Electrokinetic Transport and Surface Control2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today, the growing and aging population, and the rise of new global threats on human health puts an increasing demand on the healthcare system and calls for preventive actions. To make existing medical treatments more efficient and widely accessible and to prevent the emergence of new threats such as drug-resistant bacteria, improved diagnostic technologies are needed. Potential solutions to address these medical challenges could come from the development of novel lab-on-chip (LoC) for point-of-care (PoC) diagnostics.

    At the same time, the increasing demand for sustainable energy calls for the development of novel approaches for energy conversion and storage systems (ECS), to which micro- and nanotechnologies could also contribute.

    This thesis has for objective to contribute to these developments and presents the results of interdisciplinary research at the crossing of three disciplines of physics and engineering: electrokinetic transport in fluids, manufacturing of micro- and nanofluidic systems, and surface control and modification. By combining knowledge from each of these disciplines, novel solutions and functionalities were developed at the macro-, micro- and nanoscale, towards applications in PoC diagnostics and ECS systems.

    At the macroscale, electrokinetic transport was applied to the development of a novel PoC sampler for the efficient capture of exhaled breath aerosol onto a microfluidic platform.

    At the microscale, several methods for polymer micromanufacturing and surface modification were developed. Using direct photolithography in off-stoichiometry thiol-ene (OSTE) polymers, a novel manufacturing method for mold-free rapid prototyping of microfluidic devices was developed. An investigation of the photolithography of OSTE polymers revealed that a novel photopatterning mechanism arises from the off-stoichiometric polymer formulation. Using photografting on OSTE surfaces, a novel surface modification method was developed for the photopatterning of the surface energy. Finally, a novel method was developed for single-step microstructuring and micropatterning of surface energy, using a molecular self-alignment process resulting in spontaneous mimicking, in the replica, of the surface energy of the mold.

    At the nanoscale, several solutions for the study of electrokinetic transport toward selective biofiltration and energy conversion were developed. A novel, comprehensive model was developed for electrostatic gating of the electrokinetic transport in nanofluidics. A novel method for the manufacturing of electrostatically-gated nanofluidic membranes was developed, using atomic layer deposition (ALD) in deep anodic alumina oxide (AAO) nanopores. Finally, a preliminary investigation of the nanopatterning of OSTE polymers was performed for the manufacturing of polymer nanofluidic devices.

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    GP_PhD_Thesis
  • 202.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gatty, Hithesh K.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Pt-Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores2013In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 24, no 1, p. 015602-Article in journal (Refereed)
    Abstract [en]

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al2O3) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al2O3 layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 mu m thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al2O3 using ALD.

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  • 203.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Simultaneous replication of hydrophilic and superhydrophobic micropatterns through area-selective monomer self-assembly2016In: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 3, no 17Article in journal (Refereed)
    Abstract [en]

    The control and permanent modification of the surface properties of polymers is a critical enabler for many applications. Here, we demonstrate a strategy, which we call surface energy mimicking, for the spontaneous replication of micropatterns of surface energies ranging from hydrophilic to superhydrophobic from a mold to several replicas.

    We introduce surface energy mimicking, enabling spontaneous replication of micropatterns (2D and 2.5D) of different surface energies, and enabled by self-assembly of functional mimicking monomers within a polymer matrix. We demonstrate replication of surface energies ranging from hydrophilic to superhydrophobic, and self-assembly of picoliter-droplet arrays on replicated micropatterned arrays containing hydrophilic patches in a hydrophobic surface.

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    Surface energy mimicking _ Advanced Materials Interfaces _ submitted version
  • 204.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    SURFACE ENERGY MICROPATTERN INHERITANCE FROM MOLD TO REPLICA2014In: 27th IEEE International Conference on Micro Electro Mechanical Systems (IEEE MEMS 2014), IEEE conference proceedings, 2014, p. 96-99Conference paper (Refereed)
    Abstract [en]

    We report a novel surface-energy patterning phenomenon, in which a novel polymer composition inherits the surface energy of the medium it is in contact with during polymerization. This surface property mimicking process occurs via spontaneous selective molecular alignment of hydrophilic and hydrophobic monomers mixed into an off-stoichiometry thiol-ene (OSTE) formulation. This single-step method for simultaneous structuring and surface energy micropatterning of polymer structures is potentially more robust and lower cost than state-of-the-art processes requiring post-processing surface modification steps. We further demonstrate the self-assembly of a liquid droplet array on the replicated polymer surfaces.

  • 205.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ladhani, Laila
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sandström, Niklas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ettori, Maxime
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Lobov, Gleb
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Aerosol sampling using an electrostatic precipitator integrated with a microfluidic interface2015In: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 212, p. 344-352Article in journal (Refereed)
    Abstract [en]

    In this work, the development of a point-of-care (PoC) system to capture aerosol from litres of air directly onto a microfluidic lab-on-chip for subsequent analysis is addressed. The system involves an electrostatic precipitator that uses corona charging and electrophoretic transport to capture aerosol droplets onto a microfluidic air-to-liquid interface for downstream analysis. A theoretical study of the governing geometric and operational parameters for optimal electrostatic precipitation is presented. The fabrication of an electrostatic precipitator prototype and its experimental validation using a laboratory-generated aerosolized dye is described. Collection efficiencies were comparable to those of a state-of-the-art Biosampler impinger, with the significant advantage of providing samples that are at least 10 times more concentrated. Finally, we discuss the potential of such a system for breath-based diagnostics.

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  • 206.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Saharil, Farizah
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Karlsson, J. Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Supekar, Omkar
    Indian Institute of Technology Bombay.
    Carlborg, Carl Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Rapid mold-free manufacturing of microfluidic devices with robust and spatially directed surface modifications2014In: Microfluidics and Nanofluidics, ISSN 1613-4982, E-ISSN 1613-4990, Vol. 17, no 4, p. 773-779Article in journal (Refereed)
    Abstract [en]

    A new method that allows for mold-free, rapid and easy-to-use proto- typing of micro uidic devices comprising channels, access holes and surface modied patterns, is presented. The innovative method is based on direct photolithographic patterning of an o-stoichiometry thiol-ene (OSTE) polymer formulation, tailor-made for photolithography, which oers unprecedented spatial resolution and allow for ecient, robust and reliable, room temperature surface modication and glue-free, covalent room temperature bonding. This mold-free process does not require cleanroom equipment and therefore allows for rapid, i.e. less than one hour, design-fabricate-test cycles, using a material suited for larger scale production. The excellent photolithographic properties of this new OSTE formulation allow for high-resolution patterning in hundreds of micrometers thick layers, 200 m thick in this work. Moreover, we demonstrate robust (covalent) and spatially controlled modication of the microchannel surfaces with a contact angle of 76 degrees to hydrophobic/hydrophilic areas with contact angles of 102 and 43 degrees, respectively.

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  • 207.
    Pardon, Gaspard
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Modeling and simulation of electrostatically gated nanochannels2013In: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 199, p. 78-94Article in journal (Refereed)
    Abstract [en]

    Today, despite the growing interest in nanofluidics, the descriptions of the many complex physical phenomena occurring at this scale remain scattered in the literature. Due to the additional complexity encountered when considering electrostatic nanofluidic gating, it is important to regroup several relevant theories and discuss them with regard to this application. In this work, we present a theoretical study of electrostatically gated phenomena and propose a model for the electrostatic gating of ion and molecular transport in nanochannels. In addition to the classical electrokinetic equations, that are reviewed in this work, several relevant phenomena are considered and combined to describe gating effects on nanofluidic properties more accurately. Dynamic surface charging is accounted for and is shown to be an essential element for electrostatic gating. The autoprotolysis of water is also considered to allow for accurate computing of the surface charge. Modifications of the Nernst-Planck equations are considered for more accurate computing of the concentration profiles at higher surface potentials by accounting for ion crowding near charge walls. The sensitivity of several parameters to the electric field and ion crowding is also studied. Each of these models is described separately before their implementation in a finite element model. The model is verified against previous experimental work. Finally, the model is used to simulate the tuning of the ionic current through the nanochannel via electrostatic gating. The influence of the additional models on these results is discussed. Guidelines for potentially better gating efficiencies are finally proposed.

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  • 208.
    Qin, Tian
    et al.
    Department of Electrical and Electronic Engineering, University of Bristol.
    Bleiker, Simon J.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Rana, Sunil
    Department of Electrical and Electronic Engineering, University of Bristol.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Pamunuwa, Dinesh
    Department of Electrical and Electronic Engineering, University of Bristol.
    Performance Analysis of Nanoelectromechanical Relay-Based Field-Programmable Gate Arrays2018In: IEEE Access, E-ISSN 2169-3536, Vol. 6, p. 15997-16009Article in journal (Refereed)
    Abstract [en]

    The energy consumption of field-programmable gate arrays (FPGA) is dominated by leakage currents and dynamic energy associated with programmable interconnect. An FPGA built entirely from nanoelectromechanical (NEM) relays can effectively eliminate leakage energy losses, reduce the interconnect dynamic energy, operate at temperatures >225 °C and tolerate radiation doses in excess of 100 Mrad, while hybrid FPGAs comprising both complementary metal-oxide-semiconductor (CMOS) transistors and NEM relays (NEM-CMOS) have the potential to realize improvements in performance and energy efficiency. Large-scale integration of NEM relays, however, poses a significant engineering challenge due to the presence of moving parts. We discuss the design of FPGAs utilizing NEM relays based on a heterogeneous 3-D integration scheme, and carry out a scaling study to quantify key metrics related to performance and energy efficiency in both NEM-only and NEM-CMOS FPGAs. We show how the integration scheme has a profound effect on these metrics by changing the length of global wires. The scaling regime beyond which net performance and energy benefits is seen in NEM-CMOS over a baseline 90 nm CMOS technology is defined by an effective relay beam length of 0.5 μm , on-resistance of 200 kΩ , and a via pitch of 0.4 μm , all achievable with existing process technology. For ultra-low energy applications that are not performance critical, NEM-only FPGAs can provide close to 15× improvement in energy efficiency.

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  • 209.
    Quellmalz, Arne
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Wang, Xiaojing
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Wagner, Stefan
    AMO GmbH, Advanced Microelectronic Center Aachen (AMICA).
    Sawallich, Simon
    Protemics GmbH; Chair of Electronic Devices, Faculty of Electrical Engineering and Information Technology, RWTH Aachen University.
    Prechtl, Maximilian
    Institute of physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München.
    Hartwig, Oliver
    Institute of physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München.
    Luo, Siwei
    Institute of physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München.
    S. Duesberg, Georg
    Institute of physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München.
    Lemme, Max
    AMO GmbH, Advanced Microelectronic Center Aachen (AMICA); Chair of Electronic Devices, Faculty of Electrical Engineering and Information Technology, RWTH Aachen University.
    Gylfason, Kristinn
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering and Computer Science (EECS), Micro and Nanosystems.
    Large-Area Integration of Two-Dimensional Materials and Their Heterostructures Using Wafer Bonding2019In: Article in journal (Other academic)
  • 210. Rahiminejad, S.
    et al.
    Hansson, Jonas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. KTH, School of Biotechnology (BIO), Proteomics and Nanobiotechnology. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Kohler, E.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Klas Tommy
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology. KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haasl, Sjoerd
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH. KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Enoksson, P.
    Rapid manufacturing of OSTE polymer RF-MEMS components2017In: Proceedings of the IEEE International Conference on Micro Electro Mechanical Systems (MEMS), IEEE, 2017, p. 901-904Conference paper (Refereed)
    Abstract [en]

    This paper reports the first RF-MEMS component in OSTE polymer. Three OSTE-based ridge gap resonators were fabricated by direct, high aspect ratio, photostructuring. The OSTE polymer's good adhesion to gold makes it suitable for RF-MEMS applications. The OSTE ridge gap resonators differ in how they were coated with gold. The OSTE-based devices are compared to each other as well as to Si-based, SU8-based, and CNT-based devices of equal design. The OSTE-based process was performed outside the cleanroom, and with a fast fabrication process (∼1 h). The OSTE-based device performance is on par with that of the other alternatives in terms of frequency, attenuation, and Q-factor.

  • 211.
    Rajabi, Mina
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shafagh, Reza Zandi
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Fischer, Andreas C.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. Karlsruhe Institute of Technology (KIT), Germany.
    van der Wijngaart, Wouter
    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.
    Flexible and Stretchable Microneedle Patches with Integrated Rigid Stainless Steel Microneedles for Transdermal Biointerfacing2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 12, article id e0166330Article in journal (Refereed)
    Abstract [en]

    This paper demonstrates flexible and stretchable microneedle patches that combine soft and flexible base substrates with hard and sharp stainless steel microneedles. An elastomeric polymer base enables conformal contact between the microneedle patch and the complex topography and texture of the underlying skin, while robust and sharp stainless steel microneedles reliably pierce the outer layers of the skin. The flexible microneedle patches have been realized by magnetically assembling short stainless steel microneedles into a flexible polymer supporting base. In our experimental investigation, the microneedle patches were applied to human skin and an excellent adaptation of the patch to the wrinkles and deformations of the skin was verified, while at the same time the microneedles reliably penetrate the surface of the skin. The unobtrusive flexible and stretchable microneedle patches have great potential for transdermal biointerfacing in a variety of emerging applications such as transdermal drug delivery, bioelectric treatments and wearable bio-electronics for health and fitness monitoring.

  • 212.
    Ribet, Federico
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran N.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ultra-miniaturization of a planar amperometric sensor targeting continuous intradermal glucose monitoring2017In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 90, p. 577-583Article in journal (Refereed)
    Abstract [en]

    An ultra-miniaturized electrochemical biosensor for continuous glucose monitoring (CGM) is presented. The aim of this work is to demonstrate the possibility of an overall reduction in sensor size to allow minimally invasive glucose monitoring in the interstitial fluid in the dermal region, in contrast to larger state-of-the-art systems, which are necessarily placed in the subcutaneous layer. Moreover, the reduction in size might be a key factor to improve the stability and reliability of transdermal sensors, due to the reduction of the detrimental foreign body reaction and of consequent potential failures. These advantages are combined with lower invasiveness and discomfort for patients. The realized device consists of a microfabricated three-electrode enzymatic sensor with a total surface area of the sensing portion of less than 0.04 mm2, making it the smallest fully integrated planar amperometric glucose sensor area reported to date. The working electrode and counter electrode consist of platinum and are functionalized by drop casting of three polymeric membranes. The on-chip iridium oxide (IrOx) pseudo-reference electrode provides the required stability for measurements under physiological conditions. The device is able to dynamically and linearly measure glucose concentrations in-vitro over the relevant physiological range, while showing sufficient selectivity to known interfering species present in the interstitial fluid, with resolution and sensitivity (1.51 nA/mM) comparable to that of state-of-art commercial CGM systems. This work can therefore enable less invasive and improved CGM in patients affected by diabetes.

  • 213. Ruhl, Guenther
    et al.
    Lemme, Max Christian
    Dehe, Alfons
    Fischer, Andreas C.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Smith, Anderson
    Mems2015Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Embodiments provide a MEMS including a MEMS device and an detector circuit. The MEMS device includes a membrane, wherein a material of the membrane comprises a band gap and a crystal structure with structural elements (unit cells) connected by covalent bonds in two dimensions only. The detector circuit is configured to determine a deformation of the membrane based on a piezoresistive resistance of the material of the membrane.

  • 214.
    Safdari, Majid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Fischer, Andreas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Dvinskikh, Sergey V.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Furó, István
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Gardner, James M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry.
    Spectroscopic Material Characterization of Organic Lead Halide MaterialsManuscript (preprint) (Other academic)
  • 215.
    Saharil, Farizah
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ahlford, Annika
    Kuhnemund, Malte
    Skolimowski, Maciej
    Conde, Alvaro
    Dufva, Martin
    Nilsson, Mats
    Brivio, Monica
    Van Der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    LIGATION-BASED MUTATION DETECTION AND RCA IN SURFACE UN-MODIFIED OSTE+ POLYMER MICROFLUIDIC CHAMBERS2013In: 17th IEEE International Conference on Solid-State Sensors, Actuators and Microsystems & EUROSENSORS XXVII (IEEE TRANSDUCERS 2013), IEEE conference proceedings, 2013, p. 357-360Conference paper (Refereed)
    Abstract [en]

    For the first time, we demonstrate DNA mutation detection in surface un-modified polymeric microfluidic chambers without suffering from bubble trapping or bubble formation. Microfluidic devices were manufactured in off-stoichiometry thiol-ene epoxy (OSTE+) polymer using an uncomplicated and rapid fabrication scheme. The device performance was compared to that of PMMA and PDMS devices. In OSTE+ devices, we were able to perform ligation-based mutation detection and rolling circle amplification (RCA) assays directly on the un-modified surface without suffering from bubble formation or enzyme inhibition during bio-operation at elevated temperatures. In contrast, PMMA, PDMS and COP microfluidic devices required specific surface treatment.

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  • 216.
    Saharil, Farizah
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Forsberg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Liu, Yitong
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Bettotti, Paolo
    Kumar, Neeraj
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Wijngaart, Wouter van der
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Dry adhesive bonding of nanoporous inorganic membranes to microfluidic devices using the OSTE(+) dual-cure polymer2013In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 23, no 2, p. 025021-Article in journal (Refereed)
    Abstract [en]

    We present two transfer bonding schemes for incorporating fragile nanoporous inorganic membranes into microdevices. Such membranes are finding increasing use in microfluidics, due to their precisely controllable nanostructure. Both schemes rely on a novel dual-cure dry adhesive bonding method, enabled by a new polymer formulation: OSTE(+), which can form bonds at room temperature. OSTE(+) is a novel dual-cure ternary monomer system containing epoxy. After the first cure, the OSTE(+) is soft and suitable for bonding, while during the second cure it stiffens and obtains a Young's modulus of 1.2 GPa. The ability of the epoxy to react with almost any dry surface provides a very versatile fabrication method. We demonstrate the transfer bonding of porous silicon and porous alumina membranes to polymeric microfluidic chips molded into OSTE(+), and of porous alumina membranes to microstructured silicon wafers, by using the OSTE(+) as a thin bonding layer. We discuss the OSTE(+) dual-cure mechanism, describe the device fabrication and evaluate the bond strength and membrane flow properties after bonding. The membranes bonded to OSTE(+) chips delaminate at 520 kPa, and the membranes bonded to silicon delaminate at 750 kPa, well above typical maximum pressures applied to microfluidic circuits. Furthermore, no change in the membrane flow resistance was observed after bonding.

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  • 217.
    Saharil, Farizah
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Forsberg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Wijngaart, Wouter van der
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Dry adhesive bonding of porous alumina membranes to microstructured silicon wafers using the OSTE(+) dual-cure polymer2013In: Proceedings of the International Conference on Wafer Bonding / [ed] Roy Knechtel, 2013, p. -150Conference paper (Other academic)
  • 218.
    Saharil, Farizah
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Forsberg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Wijngaart, Wouter van der
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gylfason, Kristinn B.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Dry adhesive bonding of porous membranes to microstructured silicon wafers using the OSTE(+) dual-cure polymer2014In: Proceedings of the 10th Micronano System Workshop (MSW 2014), 2014Conference paper (Other academic)
  • 219.
    Sandström, Niklas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Integrating Biosensors for Air Monitoring and Breath-Based Diagnostics2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The air we breathe is the concern of all of us but nevertheless we only know very little about airborne particles, and especially which biological microorganisms they contain. Today, we live in densely populated societies with a growing number of people, making us particularly vulnerable to air transmission of pathogens. With the recent appearance of highly pathogenic types of avian influenza in southeast Asia and the seasonal outbreaks of gastroenteritis caused by the extremely contagious norovirus, the need for portable, sensitive and rapid instruments for on-site detection and monitoring of airborne pathogens is apparent.

    Unfortunately, the integration incompatibility between state-of-the-art air sampling techniques and laboratory based analysis methods makes instruments for in-the-field rapid detection of airborne particles an unresolved challenge.

    This thesis aims at addressing this challenge by the development of novel manufacturing, integration and sampling techniques to enable the use of label-free biosensors for rapid and sensitive analysis of airborne particles at the point-of-care or in the field.

    The first part of the thesis introduces a novel reaction injection molding technique for the fabrication of high quality microfluidic cartridges. In addition, electrically controlled liquid aspiration and dispensing is presented, based on the use of a thermally actuated polymer composite integrated with microfluidic cartridges.

    The second part of the thesis demonstrates three different approaches of biosensor integration with microfluidic cartridges, with a focus on simplifying the design and integration to enable disposable use of the cartridges.

    The third part to the thesis presents a novel air sampling technique based on electrophoretic transport of airborne particles directly to microfluidic cartridges. This technique is enabled by the development of a novel microstructured component for integrated air-liquid interfacing. In addition, a method for liquid sample mixing with magnetic microbeads prior to downstream biosensing is demonstrated.In the fourth part of the thesis, three different applications for airborne particle biosensing are introduced and preliminary experimental results are presented.

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    Thesis
  • 220.
    Sandström, Niklas
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shafagh, Reza
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Carlborg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Integration of a QCM with an OSTE cartridge2012In: MicroNano System Workshop 2012: 9th Micronano System Technology Event, Linköping, 2012Conference paper (Other academic)
  • 221.
    Sandström, Niklas
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Shafagh, Reza
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Carlborg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Simple integration of a biosensor with an OSTE polymer cartridge by low temperature dry bonding2012In: Medicinteknikdagarna 2012, Lund, 2012Conference paper (Other academic)
  • 222.
    Sandström, Niklas
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Zandi Shafagh, Reza
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gylfason, Kristinn
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Batch fabrication of polymer microfluidic cartridges for QCM sensor packaging by direct bonding2017In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 27, no 12, article id 124001Article in journal (Refereed)
    Abstract [en]

    Quartz crystal microbalance (QCM) sensing is an established technique commonly used in laboratory based life-science applications. However, the relatively complex, multi-part design and multi-step fabrication and assembly of state-of-the-art QCM cartridges makes them unsuited for disposable applications such as point-of-care (PoC) diagnostics. In this work, we present the uncomplicated manufacturing of QCMs in polymer microfluidic cartridges. Our novel approach comprises two key innovations: the batch reaction injection molding of microfluidic parts; and the integration of the cartridge components by direct, unassisted bonding. We demonstrate molding of batches of 12 off-stoichiometry thiol-ene epoxy polymer (OSTE+) polymer parts in a single molding cycle using an adapted reaction injection molding process; and the direct bonding of the OSTE+ parts to other OSTE+ substrates, to printed circuit boards, and to QCMs. The microfluidic QCM OSTE+ cartridges were successfully evaluated in terms of liquid sealing as well as electrical properties, and the sensor performance characteristics are on par with those of commercially available QCM biosensor cartridge.

  • 223.
    Sandström, Niklas
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Zandi Shafagh, Reza
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Vastesson, Alexander
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Carlborg, Fredrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    van der Wijngaart, Wouter
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haraldsson, Tommy
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Reaction injection molding and direct covalent bonding of OSTE+ polymer microfluidic devices2015In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 25, no 7Article in journal (Refereed)
    Abstract [en]

    In this article, we present OSTE+RIM, a novel reaction injection molding (RIM) process that combines the merits of off-stoichiometric thiol–ene epoxy (OSTE+) thermosetting polymers with the fabrication of high quality microstructured parts. The process relies on the dual polymerization reactions of OSTE+ polymers, where the first curing step is used in OSTE+RIM for molding intermediately polymerized parts with well-defined shapes and reactive surface chemistries. In the facile back-end processing, the replicated parts are directly and covalently bonded and become fully polymerized using the second curing step, generating complete microfluidic devices. To achieve unprecedented rapid processing, high replication fidelity and low residual stress, OSTE+RIM uniquely incorporates temperature stabilization and shrinkage compensation of the OSTE+ polymerization during molding. Two different OSTE+ formulations were characterized and used for the OSTE+RIM fabrication of optically transparent, warp-free and natively hydrophilic microscopy glass slide format microfluidic demonstrator devices, featuring a storage modulus of 2.3 GPa and tolerating pressures of at least 4 bars. 

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    fulltext
  • 224.
    Schmidt, Torsten
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Zhang, Miao
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Sychugov, Ilya
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Linnros, Jan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Nanopore arrays in a silicon membrane for parallel single-molecule detection: fabrication2015In: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 26, no 31, article id 314001Article in journal (Refereed)
    Abstract [en]

    Solid state nanopores enable translocation and detection of single bio-molecules such as DNA in buffer solutions. Here, sub-10 nm nanopore arrays in silicon membranes were fabricated by using electron-beam lithography to define etch pits and by using a subsequent electrochemical etching step. This approach effectively decouples positioning of the pores and the control of their size, where the pore size essentially results from the anodizing current and time in the etching cell. Nanopores with diameters as small as 7 nm, fully penetrating 300 nm thick membranes, were obtained. The presented fabrication scheme to form large arrays of nanopores is attractive for parallel bio-molecule sensing and DNA sequencing using optical techniques. In particular the signal-to-noise ratio is improved compared to other alternatives such as nitride membranes suffering from a high-luminescence background.

  • 225.
    Schröder, Stephan
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    A Large-Area Single-Filament Infrared Emitter for Spectroscopic Gas Sensing of EthanolManuscript (preprint) (Other academic)
    Abstract [en]

    Non-dispersive infrared spectroscopy is a promising technology for highly-accurate and maintenance-free gas sensing of ethanol. However, non-dispersive infrared sensor systems are currently too expensive for many application areas such as consumer and automotive applications. The infrared emitter is a critical and relatively costly component in today’s non-dispersive infrared systems. Here we report on a low-cost large-area single filament infrared emitter that is viable for non-dispersive infrared gas spectroscopy systems with small dimensions. The proposed infrared emitter is based on joule heating of a Kanthal filament and provides a broadband emission spectrum suitable for non-dispersive infrared gas sensing. Placement and attachment of the filament on the substrate is performed using a conventional high-speed automated wire bonding tool. Our fabrication approach enables simple and rapid rendering of a large meander-shaped emitter filament. Operation and performance of the fabricated infrared emitters were studied using Fourier transform infrared spectroscopy to analyse the effective infrared emission spectrum relevant for non-dispersive infrared gas sensing. Thermal properties such as temperature distribution across the infrared emitter was investigated. To demonstrate the viability of the meander-shaped infrared emitter for non-dispersive infrared gas sensing, the IR emitter was implemented in a non-dispersive infrared gas sensor system and the detection of varying ethanol concentrations as well as the detection of elevated breath alcohol concentration levels was demonstrated.

  • 226.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Fischer, Andreas C.
    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.
    Very high aspect ratio through silicon vias (TSVs) using wire bonding2013In: Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), 2013, IEEE conference proceedings, 2013, p. 167-170Conference paper (Refereed)
    Abstract [en]

    This paper reports a fabrication approach for very high aspect ratio through silicon vias (TSVs). The metal filling of the through via holes is implemented by adapting standard wire bonding technology. TSVs with a diameter of 30 μm and aspect ratios between 10:1 and 20:1 have been fabricated. Basic electrical characterization and optical inspection have been conducted to verify the resistance and integrity of the metal and insulator filling of the TSV.

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    T13_VHARTSVUWB
  • 227.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Gatty, Hithesh Kumar
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Roxhed, Niclas
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    A low-cost nitric oxide gas sensor based on bonded gold wires2017In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems, Institute of Electrical and Electronics Engineers (IEEE), 2017, p. 1457-1460, article id 7994334Conference paper (Refereed)
    Abstract [en]

    In this paper we report of a novel and very simple fabrication method for realizing amperometric gas sensors using conventional wire bonding technology. Working and counter electrodes are made of 360 vertically standing bond wires, entirely manufactured by a fully automated, standard wire bonding tool. Our process enables standing bond wires with a length of 1.24 mm, resulting in an extremely high aspect-ratio of 50, thus effectively increasing the surface area of the working electrode. All gas sensor electrodes are embedded in a polymer-based, solid electrolyte. Therefore, laborious handling of liquid electrolytes can be avoided. Here, we report of a nitric oxide (NO) gas sensor that is capable of detecting NO gas concentrations down to the single-digit ppm range. The proposed approach demonstrates the feasibility towards a scalable and entire back-end fabrication concept for low-cost NO gas sensors.

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    ALCNOGSBOBGW
  • 228.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Nafari, A
    Persson, K
    Westby, E
    Fischer, Andreas C.
    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.
    Haasl, Sjoerd
    KTH, School of Technology and Health (STH), Centres, Centre for Technology in Medicine and Health, CTMH.
    Stress-minimized packaging of inertial sensors using wire bonding2013In: 2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII), IEEE conference proceedings, 2013, p. 1962-1965Conference paper (Refereed)
    Abstract [en]

    This paper presents a packaging approach for inertial sensors using wire bonding technology. The die is mounted exclusively by bond wires on the front- and backside to the package. Conventional single-side die attach to substrates, such as gluing, is abandoned. The approach is characterized by its novel and symmetric die attach concept as well as its simplicity of applying a standard wire bonding process. The wire bond attachment facilitates significant reduction of thermally induced mechanical stresses. The attachment concept is characterized in terms of attachment stiffness and potential die resonances using Laser Doppler Vibrometry(LDV). White-light interferometry is used to investigate stress related warping that is induced by the die attachment process.

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    fulltext
  • 229.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. Senseair AB, Sweden.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Nafari, Alexandra
    Westby, Eskild R.
    Fischer, Andreas C.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. Karlsruhe Institute of Technology, Germany.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Haasl, Sjord
    Stress-Minimized Packaging of Inertial Sensors by Double-Sided Bond Wire Attachment2015In: Journal of microelectromechanical systems, ISSN 1057-7157, E-ISSN 1941-0158, Vol. 24, no 4, p. 781-789Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel approach for low-stress packaging of microelectromechanical system (MEMS)-based gyroscopes. The proposed approach makes use of conventional ball-stitch wire bonding. The gyroscope die is attached exclusively by means of bond wire connections between the package frame, and the top and bottom surfaces of the die. The process enables the electrical connection of metal pads on the top and the bottom side of the MEMS die within the same process. No adhesives, glue, or solder is used for the die attach. The stiffness of the proposed die attach is evaluated by scanning laser Doppler vibrometry. White-light interferometry is used to investigate stress in the die that is induced by the die attach. The bond wire attachment is compared with conventional single-sided die attach using two types of commercially available adhesives. It was found that the proposed packaging system exhibits multiple resonance modes and displays a dependence on the amount of bond wires. White-light interferometry reveals a centered bow across the die and shows low-induced stresses compared with conventionally attached dies using epoxy adhesives.

  • 230.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. SenseAir AB, Sweden.
    Rödjegård, Henrik
    SenseAir AB, Sweden.
    Fischer, Andreas C.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems. Karlsruhe Institute of Technology (KIT), Germany.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Fabrication of an Infrared Emitter using a Generic Integration Platform Based on Wire Bonding2016In: Journal of Micromechanics and Microengineering, ISSN 0960-1317, E-ISSN 1361-6439, Vol. 26, no 11, article id 115010Article in journal (Refereed)
    Abstract [en]

    This paper reports a novel approach for the fabrication of infrared (IR)emitters for non-dispersive infrared gas sensing. The proposed concept enables theintegration of superior resistive heater materials with microelectromechanical systems(MEMS) structures. In this study, non-bondable filaments made of nickel chromium areattached to mechanical attachment structures using a fully automated state-of-the-artwire bonder. The formation of the electrical contacts between the integrated filamentsand the electrical contact pattern on the substrate is performed using conventionalgold stud bumping technology. The placement accuracy of the integrated filamentsis evaluated using white-light interferometry, while the contact formation using studbumping to embed the filaments is investigated using focus ion beam milled crosssections.A proof-of-concept IR emitter has been successfully operated and heated upto 960 C in continuous mode for 3 hours.

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    FOAIEUAGIPBOWB
  • 231.
    Schröder, Stephan
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Rödjegård, Henrik
    SenseAir AB.
    Stemme, Göran
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Niklaus, Frank
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    A single wire large-area filament emitter for spectroscopic ethanol gas sensing fabricated using a wire bonding tool2017In: TRANSDUCERS 2017 - 19th International Conference on Solid-State Sensors, Actuators and Microsystems, IEEE, 2017, p. 315-318, article id 7994052Conference paper (Refereed)
    Abstract [en]

    Non-dispersive infrared (NDIR) gas spectroscopy is a highly accurate optical gas sensing technology, which has been implemented in various industrial applications. However NDIR systems remain too expensive for many consumer and automotive apphcations. The cost of the infrared (IR) emitter component is a substantial part of the total system cost. In this paper we report of a single filament IR emitter that is fabricated using wire bonding technology. Our fabrication approach offers the prospect of a fully automated assembly by means of utihzing a wire bonding tool to integrate the single filament to the MEMS structured silicon substrate. An apphcation-specific wire bond trajectory enables the mechanical attachment of the filament to form the meander-shaped emitter with a total area of 1 mm2. The fabricated IR emitter utilizes a Kanthal (FeCrAl) filament with very high thermal stability and excellent emitting properties under atmospheric conditions. The packaged IR emitter has been characterized using Fourier transform infrared (FTIR) spectroscopy to study the emitted IR spectrum with respect to the requirements of NDIR systems.

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    ALWSFIESEGSUWT
  • 232.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Novel RF MEMS Devices Enabled by Three-Dimensional Micromachining2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis presents novel radio frequency microelectromechanical (RF MEMS) circuits based on the three-dimensional (3-D) micromachined coplanar transmission lines whose geometry is re-configured by integrated microelectromechanical actuators. Two types of novel RF MEMS devices are proposed. The first is a concept of MEMS capacitors tuneable in multiple discrete and well-defined steps, implemented by in-plane moving of the ground side-walls of a 3-D micromachined coplanar waveguide transmission line. The MEMS actuators are completely embedded in the ground layer of the transmission line, and fabricated using a single-mask silicon-on-insulator (SOI) RF MEMS fabrication process. The resulting device achieves low insertion loss, a very high quality factor, high reliability, high linearity and high self actuation robustness. The second type introduces two novel concepts of area efficient, ultra-wideband, MEMS-reconfigurable coupled line directional couplers, whose coupling is tuned by mechanically changing the geometry of 3-D micromachined coupled transmission lines, utilizing integrated MEMS electrostatic actuators. The coupling is achieved by tuning both the ground and the signal line coupling, obtaining a large tuneable coupling ratio while maintaining an excellent impedance match, along with high isolation and a very high directivity over a very large bandwidth. This thesis also presents for the first time on RF nonlinearity analysis of complex multi-device RF MEMS circuits. Closed-form analytical formulas for the IIP3 of MEMS multi-device circuit concepts are derived. A nonlinearity analysis, based on these formulas and on  measured device parameters, is performed for different circuit concepts and compared to the simulation results of multi-device  conlinear electromechanical circuit models. The degradation of the overall circuit nonlinearity with increasing number of device stages is investigated. Design rules are presented so that the mechanical parameters and thus the IIP3 of the individual device stages can be optimized to achieve a highest overall IIP3 for the whole circuit.The thesis further investigates un-patterned ferromagnetic NiFe/AlN multilayer composites used as advanced magnetic core materials for on-chip inductances. The approach used is to increase the thickness of the ferromagnetic material without increasing its conductivity, by using multilayer NiFe and AlN sandwich structure. This suppresses the induced currents very effectively and at the same time increases the ferromagnetic resonance, which is by a factor of 7.1 higher than for homogeneous NiFe layers of same thickness. The so far highest permeability values above 1 GHz for on-chip integrated un-patterned NiFe layers were achieved.

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    Thesis
  • 233.
    Shah, Umer
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    RF MEMS in Competition with Semiconductor Technology2015In: 2015 International Symposium on VLSI Technology, Systems and Application (VLSI-TSA), IEEE conference proceedings, 2015Conference paper (Other academic)
    Abstract [en]

    This talk will give an overview on radio-frequency microelectromechanical systems (RF MEMS), its current state of development and performance, and comparison between commercial RF MEMS products and its semiconductor technology competition, in particular for reconfigurable RF front-ends. Furthermore, the presentation also gives an outline into emerging fields in RF/microwave engineering which are enabled by MEMS technologies, including reconfigurable millimeter and submillimeter-wave microsystems.

  • 234.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Decrossas, E.
    Jung-Kubiak, C.
    Reck, T.
    Chattopadhyay, G.
    Mehdi, I.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    500-600 GHz RF MEMS Based Tunable Stub Integrated in Micromachined Rectangular Waveguide2015In: 2015 IEEE MTT-S INTERNATIONAL MICROWAVE SYMPOSIUM (IMS), IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    This paper presents a 500-600 GHz switchable E-plane waveguide stub tuned MEMS device. It is the first ever RF MEMS component reported to be operating above 220 GHz. The micromachined E-plane stub can be blocked/unblocked from the micromachined waveguide by using a MEMS-reconfigurable surface. The surface is designed so that in the blocking state it is in the H-plane and comprises the roof of the main waveguide, whereas in the non-blocking state it comprises a transmissive E-plane surface for the stub. The measurement results of the first prototypes show a return loss better than 15 dB from 500-600 GHz. The insertion loss is better than 3 dB up to 550 GHz, and better than 4 dB up to 600 GHz. The switchable stub can be utilized as a basic reconfigurable device for tuning/matching of waveguide components under operation; the implemented prototype switchable stub achieves a (measured) tuning of 2.50 at 500 GHz, with a change in S21 better than 0.15 dB for the whole band. The paper further shows that the reconfigurable stub can also be operated in analog tuning mode. This paper also demonstrates that MEMS-reconfigurable E-plane surfaces can be designed and operated deep into the submillimeter-wave frequency range.

  • 235.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Decrossas, Emmanuel
    Jung-Kubiak, Cecile
    Reck, Theodore
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    500-550 GHz Waveguide Integrated RF MEMS Phase Sifter2016Conference paper (Refereed)
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    fulltext
  • 236.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Decrossas, Emmanuel
    Jet Propulsion Laboratory, Pasadena, CA, 91109 USA.
    Jung-Kubiak, Cecile
    Jet Propulsion Laboratory, Pasadena, CA, 91109 USA.
    Reck, Theodore
    Jet Propulsion Laboratory, Pasadena, CA, 91109 USA.
    Chattopadhyay, Goutam
    Jet Propulsion Laboratory, Pasadena, CA, 91109 USA.
    Mehdi, Imran
    Jet Propulsion Laboratory, Pasadena, CA, 91109 USA.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    500-600 GHz Submillimeter-Wave 3.3 bit RF MEMS Phase Shifter Integrated in Micromachined Waveguide2015In: Microwave Symposium (IMS), 2015 IEEE MTT-S International, IEEE conference proceedings, 2015, p. 1-4Conference paper (Refereed)
    Abstract [en]

    This paper presents a 500-600 GHz submillimeterwave MEMS-reconfigurable phase shifter. It is the first ever RF MEMS component reported to be operating above 220 GHz. The phase shifter is based on a micromachined rectangular waveguide which is loaded by 9 E-plane stubs, which can be individually blocked by using MEMS–reconfigurable surfaces. The phase-shifter is composed of three metallized silicon chips which are assembled in H-plane cuts of the waveguide. The measurement results of the first prototypes of the MEMS reconfigurable phase shifter show a linear phase shift of 20° in 10 steps (3.3 bit) and have a return loss better than 15 dB from 500-600 GHz. The insertion loss is better than 3 dB up to 540 GHz, and better than 5 dB up to 600 GHz for all phase states, of which the major part is contributed by the assembly of the microchips between waveguide flanges which has a reproducibility error between 2 and 6 dB measured for reference chips.

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    fulltext
  • 237.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Decrossas, Emmanuel
    Jung-Kubiak, Cecile
    Reck, Theodore
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Micromachined Waveguide Integrated RF MEMS Phase Sifter Operating between 500-600 GHz2015Conference paper (Refereed)
    Abstract [en]

    This paper presents a 500-600 GHz submillimeter- wave MEMS-reconfigurable phase shifter. It is the first ever RF MEMS component reported to be operating above 220 GHz. The phase shifter is based on a micromachined rectangular waveguide which is loaded by 9 E-plane stubs, which can be individually blocked by using MEMS–reconfigurable surfaces. The phase-shifter is composed of three metallized silicon chips which are assembled in H-plane cuts of the waveguide.

    Download full text (pdf)
    fulltext
  • 238.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Decrossas, Emmanuel
    Jung-Kubiak, Cecile
    Reck, Theodore
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Submillimeter-Wave 3.3-bit RF MEMS Phase Shifter Integrated in Micromachined Waveguide2016In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, Vol. 6, no 5, p. 706-715, article id 7513394Article in journal (Refereed)
    Abstract [en]

    This paper presents a submillimeter-wave 500–550-GHz MEMS-reconfigurable phase shifter, which is based on loading a micromachined rectangular waveguide with 9 E-plane stubs. The phase shifter uses MEMS-reconfigurable surfaces to individually block/unblock the E-plane stubs from the micromachined waveguide. Each MEMS-reconfigurable surface is designed so that in the nonblocking state, it allows the electromagnetic wave to pass freely through it into the stub, while in the blocking state, it serves as the roof of the main waveguide and blocks the wave propagation into the stub. The phase-shifter design comprises three micromachined chips that are mounted in the H-plane cuts of the rectangular waveguide. Experimental results of the first device prototypes show that the microelectromechanical system (MEMS)-reconfigurable phase shifter has a linear phase shift of 20° in ten discrete steps (3.3 bits). The measured insertion loss is better than 3 dB, of which only 0.5–1.5 dB is attributed to the MEMS surfaces and switched stubs, and the measured return loss is better than 15 dB in the design frequency band of 500–550 GHz. It is also shown that the major part of the insertion loss is attributed to misalignment and assembly uncertainties of the micromachined chips and the waveguide flanges, shown by simulations and reproducibility measurements. The MEMS-reconfigurable phase shifter is also operated in an analog tuning mode for high phase resolution. Furthermore, a detailed study has been carried out identifying the reason for the discrepancy between the simulated (90°) and the measured (20°) phase shift. Comb-drive actuators with spring constant variations between 2.13 and 8.71 N/m are used in the phase shifter design. An actuation voltage of 21.94 V with a reproducibility better than σ=0.0503 V is measured for the actuator design with a spring constant of 2.13 N/m. Reliability measurement on this actuator was performed in an uncontrolled laboratory environment and showed no deterioration in the functioning of the actuator observed over one hundred million cycles.

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  • 239.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Liljeholm, Jessica
    Campion, James
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Ebefors, Thorbjörn
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Low Loss High Linearity RF Interposers Enabled by Through-Glass Vias2018In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 28, no 11, p. 960-962Article in journal (Refereed)
    Abstract [en]

    This letter reports on a new low-loss and high linearity3-D wafer-level interposer technology enabled by throughglass vias (TGVs) with an inverted via configuration. Theproposed TGV utilizes a tapered via sidewall profile to achievea void-free conformal metal coverage with lower process timeand fewer fabrication steps than a fully filled conventional TGV.Measurement results for a single 100 μm tall TGV show aninsertion loss of 0.014 dB at 10 GHz and a DC resistanceof 28 mΩ. Finally, this letter reports for the first time onnonlinearity measurements of TGVs. Single-tone measurementsshow that the third harmonic level for a coplanar waveguide(CPW) TGV test structure is only 2 dB higher than a referenceCPW through line without TGVs, indicating an overall excellentlinearity performance.

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  • 240.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Liljeholm, Jessica
    Silex Microsystems.
    Ebefors, Thorbjörn
    Silex Microsystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Permeability Enhancement by Multilayer Ferromagnetic Composites for Magnetic-Core On-Chip Inductors2014In: IEEE Microwave and Wireless Components Letters, ISSN 1531-1309, E-ISSN 1558-1764, Vol. 24, no 10, p. 677-679Article in journal (Refereed)
    Abstract [en]

    This letter reports about unpatterned ferromagnetic NiFe/AlN multilayer composites used as advanced magnetic core materials for on-chip and interposer integrated inductances. The proposed composite structure reduces RF induced currents and thus pushes the permeability cutoff to beyond 3.7 GHz, which is by a factor of 7.1 higher than for homogeneous NiFe layers of same thickness. To the best knowledge of the authors, we achieve the highest effective relative permeability of 28 at 1 GHz, highest ferromagnetic resonance frequency and highest inductance enhancement factor above 1 GHz ever reported for devices based on on-chip unpatterned NiFe magnetic cores. A single loop inductor is also implemented as a technology demonstrator, achieving an inductance enhancement of 4.8 and a quality factor enhancement of 4.5 at 400 MHz.

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  • 241.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Characterization of High-Q Laterally Moving RF MEMS Tuneable Capacitor2013In: European Microwave Week 2013, EuMW 2013 - Conference Proceedings; EuMC 2013: 43rd European Microwave Conference, 2013, p. 1323-1326Conference paper (Refereed)
    Abstract [en]

    This paper investigates an implementation of RF MEMS tuneable capacitors based on the lateral displacement of the sidewalls of a three-dimensional micromachined coplanar transmission line. The concept achieves high Q since the mechanical actuation elements are completely de-coupled from the RF path, which is achieved by capacitive coupling of the ground signal to the moving sidewall. The fabricated capacitor has a tuning range of 40.53 to 60 fF (C-max/C-min = 1.48) in three discrete steps. This paper reports for the first time on Q-factor measurements, reliability, self-actuation robustness measurements, and linearity analysis. The Q-factor was determined by a transmission-line resonator as 88 at 40 GHz, resulting in a Qxf product of 3.52x10(12) which is higher than of any previously reported tuneable capacitor. Measurement data demonstrates high self-actuation robustness of 41.5 dBm at actuation and release voltages of 30.7 V and 21.15 V, a pull-in time of 60 mu s, and a mechanical resonance frequency of 5.3 kHz. The linearity of the device has been determined to an IIP3 of 71.4, 74.4 and 91.0 dBm for the three states of the capacitor. Reliability tests up to 1 billion cycles show no detectable performance degradation of this all-metal tuneable capacitor concept.

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  • 242.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Characterization of High-Q Laterally Moving RF MEMS Tuneable Capacitor2013In: 2013 8TH EUROPEAN MICROWAVE INTEGRATED CIRCUITS CONFERENCE (EUMIC), IEEE , 2013, p. 352-355Conference paper (Refereed)
    Abstract [en]

    This paper investigates an implementation of RF MEMS tuneable capacitors based on the lateral displacement of the sidewalls of a three-dimensional micromachined coplanar transmission line. The concept achieves high Q since the mechanical actuation elements are completely de-coupled from the RF path, which is achieved by capacitive coupling of the ground signal to the moving sidewall. The fabricated capacitor has a tuning range of 40.53 to 60 fF (C-max/C-min = 1.48) in three discrete steps. This paper reports for the first time on Q-factor measurements, reliability, self-actuation robustness measurements, and linearity analysis. The Q-factor was determined by a transmission-line resonator as 88 at 40 GHz, resulting in a Qxf product of 3.52x10(12) which is higher than of any previously reported tuneable capacitor. Measurement data demonstrates high self-actuation robustness of 41.5 dBm at actuation and release voltages of 30.7 V and 21.15 V, a pull-in time of 60 mu s, and a mechanical resonance frequency of 5.3 kHz. The linearity of the device has been determined to an IIP3 of 71.4, 74.4 and 91.0 dBm for the three states of the capacitor. Reliability tests up to 1 billion cycles show no detectable performance degradation of this all-metal tuneable capacitor concept.

  • 243.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Reck, Theodore
    Decrossas, Emmanuel
    Jung-Kubiak, Cecile
    Frid, Henrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    500-750 GHz submillimeter-wave MEMS waveguide switch2016Conference paper (Refereed)
    Abstract [en]

    This paper presents a 500-750 GHz waveguide based single-pole single-throw (SPST) switch achieving a 40% bandwidth. It is the first ever RF MEMS switch reported to be operating above 220 GHz. The switch is based on a MEMS-reconfigurable surface which can block the wave propagation in the waveguide by short-circuiting the electrical field lines of the TE10 mode. The switch is designed for optimized isolation in the blocking state and for optimized insertion loss in the non-blocking state. The measurement results of the first prototypes show better than 15 dB isolation in the blocking state and better than 3 dB insertion loss in the non-blocking state for 500-750 GHz. The higher insertion loss is mainly attributed to the insufficient metal thickness and surface roughness on the waveguide sidewalls. Two switch designs with different number of blocking elements are fabricated and compared. The overall switch bandwidth is limited by the waveguide only and not by the switch technology itself.

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  • 244.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Reck, Theodore
    Decrossas, Emmanuel
    Jung-Kubiak, Cecile
    Frid, Henrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Micromachined Waveguide Integrated RF MEMS Switch Operating between 500-750 GHz2016Conference paper (Refereed)
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  • 245.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Reck, Theodore
    Frid, Henrik
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Jung-Kubiak, Cecile
    Chattopadhyay, Goutam
    Mehdi, Imran
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    A 500–750 GHz RF MEMS Waveguide Switch2017In: IEEE Transactions on Terahertz Science and Technology, ISSN 2156-342X, E-ISSN 2156-3446, Vol. 7, no 3, p. 326-334Article in journal (Refereed)
    Abstract [en]

    This paper reports on a submillimeter-wave 500-750 GHz micorelectromechanical systems (MEMS) waveguide switch based on a MEMS-reconfigurable surface to block/unblock the wave propagation through the waveguide. In the non-blocking state, the electromagnetic wave can pass freely through the MEMS-reconfigurable surface, while in the blocking state, the electric field lines of the TE10 mode are short-circuited that blocks the wave propagation through a WM-380 (WR-1.5) waveguide. A detailed design parameter study is carried out to determine the best combination of the number of horizontal bars and vertical columns of the MEMS-reconfigurable surface for achieving a low insertion loss in the non-blocking state and a high isolation in the blocking state for the 500-750 GHz band. Two different switch concepts relying either on an ohmic-contact or a capacitive-contact between the contact cantilevers have been implemented. The measurements of the switch prototypes show a superior RF performance of the capacitive-contact switch. The measured isolation of the capacitive-contact switch designed with an 8 μm contact overlap is 19-24 dB and the measured insertion loss in the non-blocking state is 2.5-3 dB from 500 to 750 GHz including a 400 μm long micromachined waveguide section. By measuring reference chips, it is shown that the MEMS-reconfigurable surface contributes only to 0.5-1 dB of the insertion loss, while the rest is attributed to the limited sidewall metal thickness and to the surface roughness of the 400 μm long micromachined waveguide section. Finally, reliability measurements in an uncontrolled laboratory environment on a comb-drive actuator with an actuation voltage of 28 V showed no degradation in the functioning of the actuator over one hundred million cycles. The actuator was also kept in the actuated state for ten days and showed no sign of failure or deterioration.

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  • 246.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Analysis of linearity degradation in multi-stage RF MEMS circuits2013In: Micro Electro Mechanical Systems (MEMS), 2013 IEEE 26th International Conference on, IEEE conference proceedings, 2013, p. 749-752Conference paper (Refereed)
    Abstract [en]

    This paper reports for the first time on RF nonlinearity analysis of complex multi-device RF MEMS circuits. The nonlinearity analysis is done for the two most commonly-used RF MEMS tuneable-circuit concepts, i.e. digital MEMS varactor banks and MEMS switched capacitor banks. In addition, the nonlinearity of a novel MEMS tuneable capacitor concept by the authors, based on a MEMS actuator with discrete tuning steps, is discussed. This paper presents closed-form analytical formulas for the IIP3 (nonlinearity) of the three MEMS multi-device circuit concepts, and an analysis of the nonlinearity based on measured device parameters (capacitance, gap), of the different concepts. Finally, this paper also investigates the effect of scaling of the circuit complexity, i.e. the degradation of the overall circuit linearity depending on the number of stages/bits of the MEMS-tuning circuit.

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  • 247.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Analysis of Linearity Deterioration in Multidevice RF MEMS Circuits2014In: IEEE Transactions on Electron Devices, ISSN 0018-9383, E-ISSN 1557-9646, Vol. 61, no 5, p. 1529-1535Article in journal (Refereed)
    Abstract [en]

    This paper presents for the first time an RF nonlinearity analysis of complex multidevice radio frequency microelectromechanical system (RF MEMS) circuits. The IIP3 of different RF MEMS multidevice tunable-circuit concepts including digital MEMS varactor banks, MEMS switched capacitor banks, distributed MEMS phase shifters, and MEMS tunable filters, is investigated. Closed-form analytical formulas for the IIP3 of MEMS multidevice circuit concepts are derived. A nonlinearity analysis, based on measured device parameters, is presented for exemplary circuits of the different concepts using a multidevice nonlinear electromechanical circuit model implemented in Agilent Advanced Design System. The results of the nonlinear electromechanical model are also compared with the calculated IIP3 using derived equations for the digital MEMS varactor bank and MEMS switched capacitor bank. The degradation of the overall circuit linearity with increasing number of device stages is also investigated, with the conclusion that the overall circuit IIP3 is reduced by half when doubling the number of stages, if proper design precautions are not taken. Design rules are presented so that the mechanical parameters and thus the IIP3 of the individual device stages can be optimized to achieve a higher overall IIP3 for the whole circuit. In addition, the nonlinearity of a novel MEMS tunable capacitor concept introduced by the authors, based on an MEMS actuator with discrete tuning steps, is discussed and the IIP3 is calculated using derived analytical formulas.

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  • 248.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    High-Directivity MEMS-Tunable Directional Couplers for 10–18-GHz Broadband Applications2013In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 61, no 9, p. 3236-3246Article in journal (Refereed)
    Abstract [en]

    This paper reports on two novel concepts of areaefficient, ultra-wideband, MEMS-reconfigurable coupled line directional couplers, whose coupling is tuned by mechanically changing the geometry of 3-D micromachined coupled transmission lines, utilizing integrated MEMS electrostatic actuators. Concept 1 is based on symmetrically changing the geometry of the ground coupling of each signal line, while Concept 2 is simultaneously varying both the ground coupling and the coupling between the two signal lines. This enables uniform and well predictable performance over a very large frequency range, in particular a constant coupling ratio while maintaining an excellent impedance match, along with high isolation and a very high directivity. For an implemented micromachined prototype 3-to-6 dB coupler based on Concept 1, the measured isolation is better than 16 dB, and the return loss and directivity are better than 10 dB over the entire bandwidth from 10 to 18 GHz. Concept 2 presents an even more significant improvement. For an implemented 10-to-20 dB prototype based on Concept 2, the measured isolation is better than 40 dB and the return loss is better than 15 dB over the entire bandwidth from 10 to 18 GHz for both states. The directivities for both states are better than 22 dB and 40 dB, respectively, over the whole frequency range. The measured data fits the simulation very well, except for higher through-port losses of the prototype devices. All devices have been implemented in an SOI RF MEMS fabrication process. Measured actuation voltages of the different actuators are lower than 35 V. Reliability tests were conducted up to 500 million cycles without device degradation.

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  • 249.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Multi-Position RF MEMS Tunable Capacitors Using Laterally Moving Sidewalls of 3-D Micromachined Transmission Lines2013In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 61, no 6, p. 2340-2352Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel concept of RF microelectromechanical systems (MEMS) tunable capacitors based on the lateral displacement of the sidewalls of a 3-D micromachined coplanar transmission line. The tuning of a single device is achieved in multiple discrete and well-defined tuning steps by integrated multi-stage MEMS electrostatic actuators that are embedded inside the ground layer of the transmission line. Three different design concepts, including devices with up to seven discrete tuning steps up to a tuning range of 58.6 to 144.5 fF, (C-max/C-min = 2.46) have been fabricated and characterized. The highest Q factor, measured by a weakly coupled transmission-line resonator, was determined as 88 at 40 GHz and was achieved for a device concept where the mechanical suspension elements were completely de-coupled from the RF signal path. These devices have demonstrated high self-actuation robustness with self-actuation pull-in occurring at 41.5 and 47.8 dBm for mechanical spring constants of 5.8 and 27.7 N/m, respectively. Nonlinearity measurements revealed that the third-order intermodulation intercept point (IIP3) for all discrete device states is above the measurement-setup limit of 68.5 dBm for our 2.5-GHz IIP3 setup, with a dual-tone separation of 12 MHz. Based on capacitance/gap/spring measurements, the IIP3 was calculated for all states to be between 71-91 dBm. For a mechanical spring design of 5.8 N/m, the actuation and release voltages were characterized as 30.7 and 21.15 V, respectively, and the pull-in time for the actuator bouncing to drop below 8% of the gap was measured to be 140 mu s. The mechanical resonance frequencies were measured to be 5.3 and 17.2 kHz for spring constant designs of 5.8 and 27.7 N/m, respectively. Reliability characterization exceeded 1 billion cycles, even in an uncontrolled atmospheric environment, with no degradation in the pull-in/pull-out hysteresis behavior being observed over these cycling tests.

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  • 250.
    Shah, Umer
    et al.
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Sterner, Mikael
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Oberhammer, Joachim
    KTH, School of Electrical Engineering (EES), Micro and Nanosystems.
    Nonlinearity Determination and Linearity Degradation in RF MEMS Multi-Device Circuits2013Conference paper (Refereed)
    Abstract [en]

    This paper reports for the first time on RF nonlinearity analysis of complex multi-device RF MEMS circuits. The nonlinearity analysis is done for the two most commonly-used RF MEMS tuneable-circuit concepts, i.e. digital MEMS varactor banks and MEMS switched capacitor banks. In addition, the nonlinearity of a novel MEMS tuneable capacitor concept by the authors, based on a MEMS actuator with discrete tuning steps, is discussed. This paper presents closed-form analytical formulas for the IIP3 (nonlinearity) of the three MEMS multi-device circuit concepts, and an analysis of the nonlinearity based on measured device parameters (capacitance, gap), of the different concepts. Finally, this paper also investigates the effect of scaling of the circuit complexity, i.e. the degradation of the overall circuit linearity depending on the number of stages/bits of the MEMS-tuning circuit.

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