High Q Micro-machined Cavity Resonator Filter in Low-Cost Silicon Technology

This paper demonstrates a two-pole filter based on high Q micro-machined cavity resonators for operation at 20 GHz. The filter implements a novel inter-resonator coupling cavity placed above the inter-cavity wall separating the resonators and etched out of silicon using the same KOH-etching process as the one used to realised the cavity resonators. The Q-factor of a single cavity resonator is measured as well as the response of the two-pole filter. The filter presented here constitutes the first development step toward a more sophisticated fixed as well as tunable four-pole filter aiming at the replacement of bulky waveguide filters mounted in a majority of satellite transceivers.