Monocrystalline-Silicon Based RF MEMS Devices
This is an announcement of the public defence of the PhD candidate Mikael Sterner, defending his thesis entitled "Monocrystalline-silicon based RF MEMS devices", on Friday, Nov. 23rd, at 10:00 at KTH in lecture hall F3, Lindstedtsvägen 26, ground floor.
His opponent, Prof. Roberto Sorrentino, University of Perugia, Italy, will give a seminar on his activities in RF/microwave micro-electromechanical systems, including the company RF Microtech whose president he is, on the same day at 14:00-15:00 in lecture room Q24, Osquldas väg 6B, 1st floor.
Welcome to the defence and the seminar!
Joachim Oberhammer
Time: Fri 2012-11-23 10.00
Location: Lecture hall F3, Lindstedtsvägen 26
Subject area: Mikrosystemteknik
Doctoral student: Mikael Sterner
Opponent: Professor Roberto Sorrentino
Supervisor: Associate Professor Joachim Oberhammer
Thesis abstract
This thesis presents novel radio-frequency microelectromechanical (RF MEMS) devices, for microwave and millimeter wave applications, designed for process robustness and operational reliability using monocrystalline silicon as structural material. Two families of RF MEMS devices are proposed. The first comprises reconfigurable microwave components integrated with coplanar waveguide transmission lines in the device layer of silicon-on-insulator wafers. The second consists of analog tuneable millimeter wave high-impedance surface arrays.
The first group of reconfigurable microwave components presented in this thesis is based on a novel concept of integrating MEMS functionality into the sidewalls of three-dimensional micromachined transmission lines. A laterally actuated metal-contact switch was implemented, with the switching mechanism completely embedded inside the signal line of a coplanar-waveguide transmission line. The switch features zero power-consumption in both the on and the off state since it is mechanically bistable, enabled by interlocking hooks. Both twoport and three-port configurations are presented. Furthermore, tuneable capacitors based on laterally moving the ground planes in a micromachined coplanarwaveguide transmission line are demonstrated.
The second group of reconfigurable microwave components comprises millimeter-wave high-impedance surfaces. Devices are shown for reflective beam steering, reflective stub-line phase shifters and proximity based dielectric rod waveguide phase shifters, as well as a steerable leaky-wave antenna device based on the same geometry. Full wafer transfer bonding of symmetrically metallized monocrystalline silicon membranes, for near-ideal stress compensation, is used to create large arrays of distributed MEMS tuning elements. Furthermore, this thesis investigates the integration of reflective MEMS millimeter wave devices in rectangular waveguides using a conductive adhesive tape, and the integration of substrates with mismatched coefficients of thermal expansion.