Triangular Cavity Multi-Passband HMSIW Filter Based on Odd-Even Mode Analysis

This letter proposes a multi-passband half-mode substrate integrated waveguide (HMSIW) filter based on the theory of odd and even mode analysis. The adopts triangular HMSIW cavity cut along diagonal rectangle. By etching two dual-mode resonators, resonant resonator is coupled with odd-even to achieve multiple passbands. defected ground structure (DGS) can reduce resonance frequency without increasing volume cavity, making it easier couple frequencies resonator. input output ports are directly through microstrip line. In this way, adds an additional coupling path filter, which increases out-of-band suppression changing performance in passband, improves overall filter. To prove feasibility above method, was fabricated tested. center three passbands 2.98 GHz, 4.78 6.62 respectively. return loss passband better than −15 dB, insertion 2 dB. measured results have good agreement simulation results.