A horizontally integrated micromachined filter

A 32 GHz filter constructed of micromachined cavities in silicon is presented. The filter structure consists of two side-by-side, horizontally-oriented cavities, which are coupled by evanescent waveguide sections, and are fed by microstrip lines through slot apertures. The measured results are presented and compared to those predicted by an FEM model. The simulated filter response has a bandwidth of 2.3% centered at 31.74 GHz with an insertion loss of 1.2 dB. The measured performance indicates a 2.2% bandwidth centered at 31.70 GHz with a de-embedded insertion loss of 1.2 dB, and an unloaded Q of 1422.