K-band MEMS-based frequency adjustable waveguide filter for mobile back-hauling

This paper presents the first experimental results of a novel MEMS-based waveguide filter for mobile back-hauling at K-band with adjustable centre frequency. The tuning concept employs commercial packaged RF MEMS switches, wire-bonded within a rectangular cavity. The switches are used to perturb the current distribution of the TE101 mode so as to tune the resonant frequency of the cavity. A tuning range up to 2% with unloaded Qs of the order of 1000 in K-band can be obtained. A 2nd order filter prototype employing commercially available MEMS on silicon substrate has been tested. Measurements show a 160 MHz frequency shift (0.7%) and Qs up to 1000 using only one MEMS per resonator. New prototypes using low-loss substrate MEMS (e.g. quartz) will be fabricated in order to get higher Qs.