A Substrate Integrated Waveguide Filter Based on Quartz Glass Substrate with Wide Stop Band

Abstract

This paper proposes a type of substrate integrated waveguide (SIW) filter with wide stop band. Firstly, the structure uses a quartz glass-based substrate, which has lower losses compared to silicon-based substrates. Secondly, the transmission of TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">102</inf> and TE <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">201</inf> modes is effectively suppressed by the deep coupling feeder effect of the input and output and the horizontal coupling between the cavities. The multi-layer structure realizes electrical coupling to improve the squareness and reduce the area of the filter. Under the above characteristics, the filter is composed of a sixth-order resonator, the center frequency <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$f_{0}=20.2\text{GHz}$</tex> , the bandwidth is 1.5GHz, the insertion loss is −2dB, the in-band return loss is less than −15dB, and the out-of-band suppression can be achieved within <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2.05f_{0}$</tex> less than-40dB effect.