Abstract:A new technique called Substrate Integrated Waveguide(SIW) was proposed, and then its dominant mode(TE10) was briefly analyzed. In order to miniaturize the millimeter wave circuit system, this study improved the traditional chain SIW filter and brought forward a new type of compact configuration with chamfer angle. Based on these two structures, the bandpass filters were designed with the center frequency of 31.15 GHz, the Fractional Bandpass Width(FBW) of 7.7%, and the maximum insertion loss less than 1.9 dB. The simulation results showed that when compared with the traditional one，the compact SIW filter with chamfer angle tended to be more structurally compact, with the maximum length being shortened by half. Moreover, the performance of the filter was getting better than before.