High-Q MEMS-based bandwidth-reconfigurable E-plane filters

This paper presents an innovative concept for the design and realisation of bandwidth reconfigurable E-plane filters with very high Q-factor. Ohmic cantilever MEMS switches are arranged at both sides of the metallic central septa of an E-plane filter so as to provide a reconfigurable septum length and consequently a bandwidth tuning. The effective length of each septum can be changed by activating or deactivating the MEMS switches, so as to control the filter couplings. The proposed approach yields higher Q-factors compared to other bandwidth tuning approaches employing MEMS in planar technology. The preliminary measurements of a 3^rd order bandpass filter at 10 GHz show a relative bandwidth change from 3.4% to 4.8% (141% tuning) with unchanged central frequency and a Q-factor above 1100.