Electromagnetic and mechanical analysis for micromachined filter

This paper describes micromachined bandpass filters, design at K band, on GaAs and silicon substrates, respectively. The performance of a three-layer (supported by 2 μm AlGaAs membrane) and two-layer (solid) filter structure on a GaAs substrate are compared and discussed. Electromagnetic simulation shows less than 1 dB insertion loss and acceptable stop band rejection for both the solid two-layer and membrane three-layer filter structure. A two-layer filter structure with a cavity on the bottom wafer is also proposed on a silicon substrate, where 10 μm SiO₂ is used as a membrane. Both EM simulation results and mechanical analysis are provided. The boundary element method is used in mechanical simulation and a deflection of about 1.338 μm is obtained for the SiO₂ membrane.