Development of high performance 6--18 GHz tunable/switchable RF MEMS filters and their system implications.

Abstract

The development of RF MEMS technology has accelerated considerably over the past several years. RF MEMS technology provides immense capabilities for a new generation of reconfigurable networks such as phase shifters, matching networks, antennas and tunable filters used in wireless/satellite communication systems, automotive/defense radar systems and instrumentation equipment. RF MEMS switched capacitors are very good candidates as tuning elements for reconfigurable networks: They provide wide tuning range, very high-Q, excellent linearity, high RF power handling capability and their DC power consumption is negligible. The focus of this thesis is the development of wideband RF MEMS tunable filters. The thesis presents the first 6--10 GHz miniaturized lumped element RF MEMS tunable filter with excellent linearity, low loss, impedance match over the tuning range, and very fine frequency scanning resolution (less than 1 dB crossovers between the 16 different tunable filter steps). The thesis also presents the first 12--18 GHz coplanar-waveguide slow-wave resonator RF MEMS filter with also excellent linearity, very fine frequency resolution, reasonable match over the tuning range and very small size (8 mm x 4 mm). RF MEMS devices must also be packaged and encapsulated in a stable environment for high reliability, and the wafer-scale packaging technique is a well proven solution. The thesis presents a microstrip wafer-scale package for DC-26 GHz applications with very low insertion loss and an impedance match better than -20 dB over the entire band. Also, the impact of RF MEMS, BST and GaAs reconfigurable networks on the systems-level performance such as spectral re-growth in WCDMA signals is discussed. The thesis concludes with future projects involving RF MEMS tunable filters, packaging and reconfigurable systems.