Integrated Substrate Gap Waveguide Bandpass Filter With Wide Stopband

This paper presents a wide-stopband bandpass filter based on integrated substrate gap waveguide (ISGW). The filter achieves mode coupling of TE101 and TE102 in the cavity by means of a split slot which generates transmission zero (TZ) and optimizes stopband. Moreover, the resonant frequency of the TE102 mode is reduced towards the resonant frequency of the TE101 mode and forms a passband, thus eliminating the effect of the TE102 mode in achieving a wide stopband. At the same time, the filter also uses orthogonal transmission technology and harmonic interleaving technology to suppress higher order mode, so as to achieve wider stopband. The simulation results show that the center frequency of the filter is 21.1GHz, the bandwidth of -3dB is 4.16%, the stopband suppression is better than -20dB at 23.63GHz-45GHz, and the stopband width reaches 2.13f0.