A Compact Millimeter-Wave Multilayer Mems Bandpass Filter on High-Resistivity Silicon Substrate

This article proposes a compact millimeter-wave MEMS bandpass filter based on multilayer high-resistivity silicon substrates. A through silicon via (TGV) with a patch in the substrate integrated waveguide (SIW) structure is used as a resonator with a compact size. Four resonators are used to construct the filter with in-line topology. A novel feeding structure is designed to generate transmission zeros near the passband to improve the skirt selectivity. As compared to the traditional SIW resonators, the proposed design shows great size reduction. For verification, a filter covering <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$37-44 \text{GHz}$</tex> is designed. It has an insertion loss of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.8 ~\text{dB}, 1-\text{dB}$</tex> relative fractional bandwidth (FBW) of 17 %, out-of-band suppression of greater than 40 dB at the center frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{0} \pm 0.2 f_{0}$</tex>, and a compact chip size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1 ~\text{mm} \times 3 ~\text{mm} \times 0.55 ~\text{mm}$</tex>. Simulation results of the proposed design show excellent performances of a low insertion loss and high spurious passbands, which is useful in 5 G mm-wave applications.