Research and design of millimeter-wave filter based on SIW technology

In this paper, two fourth-order coupled bandpass filters are designed based on the substrate integrated waveguide (SIW) structure. Three-dimensional full-wave electromagnetic field simulation software-high frequency structure simulator (HFSS) was used to simulate, design and optimize the two designed filters. According to the analysis of the simulation results, the two filters operate at millimeter-wave band. The first one realizes the Chebyshev type response with a center frequency of 20 GHz, a bandwidth of 2 GHz, insertion loss within passband less than 1.5 dB, return loss less than -20 dB and the attenuation of the signal in the stopband can reach 50 dB. The other one realizes the quasi-elliptic functional response with a center frequency of 29.1 GHz, a bandwidth of 300 MHz, insertion loss within passband less than 1 dB, return loss less than -20 dB and two notches are implemented in the transition of passband to stopband. The simulation results show that the introduction of substrate integrated waveguide structure in the millimeter wave filter design is conducive to optimize the filter size and obtain better filter performance, which is an important direction in the development of millimeter wave filter.