A switched high-T_csuperconductor microstrip resonator using a MEM switch

Abstract

We have used a high performance (less than 0.05 dB insertion loss, greater than 30 dB isolation) high-Tc superconductor based micro electromechanical (MEM) switch to insert a shunt microstrip resonator into a microstrip transmission line thus forming a ‘T’-resonator structure. This allows the insertion of a series of notches and peaks (depending on termination of the shunt line and the harmonic in use) into the transmission line's transfer function thus forming a rudimentary switched filter. The ‘T’-resonator is designed for a resonant frequency of 3.5 GHz and is implemented using high-Tc YBa2Cu3O7, BaTiO3 is used as a dielectric patch underneath a suspended gold membrane. The design, fabrication, testing and most recent results are presented in this paper.

Cryogenic Performance of RF MEMS Switch Contacts

“…The switches showed no changes in mechanical stability during or after testing at cryogenic temperatures. The increased pull-in voltage for fixed-fixed capacitive switches at cryogenic reported in [6]- [12] was not observed at 77 K for the cantilever-type switches used for experimentation. In addition, the hysteresis in pull-in voltage reported in [11] after temperature cycling was not present.…”

“…Cryogenic temperatures have adverse effects on the operational stability and longevity of capacitive MEMS switches. The pull-in voltage substantially increases, and capacitance decreases with decreasing temperature [6]- [12]. An increased mortality rate for switches operating at cryogenic temperatures has also been reported [9].…”

“…Interest also exists for integrating RF MEMS devices with high-Tc superconductors (HTS); demonstrated applications with integrated MEMS include an HTS microstrip resonator [12] and a tunable HTS filter [13]. Cryogenic temperatures have adverse effects on the operational stability and longevity of capacitive MEMS switches.…”

Design, simulation, and fabrication of a MEMs switched superconducting microstrip hairpin filter

“…This switch showed minimum insertion loss and significant isolation compared to conventional solid state switching devices. Further work was performed where simple devices, such as switched microstrip [2,3,8] and coplanar [4] ''T'' resonators on superconductor, made use of a single switch. These devices showed satisfactory RF responses and motivated further investigation of more complex devices with multi-switch elements.…”

Performance of RF MEMS switches at low temperatures

“…Recently, there has been research interest in the application of the high-Tc superconductor (HTS) in combination with RF MEMS devices. A switched HTS microstrip resonator and a tunable HTS filter, both incorporating MEMS technology, have been demonstrated [2,3]. While successful integration of MEMS switches onto HTS devices is a challenging task, the operational issue of RF MEMS switches at low temperatures is another key consideration to many microwave and system designers.…”