Transverse mental iris filter based on substrate integrate waveguide cavities

A novel indirect optimum design method for SIW filter is proposed. In the two-step design method, the design of a conventional waveguide filter is firstly optimized by adopting MMM, and then the filter based on SIW cavity is obtained by the conventional formula that transforms common waveguide structure into SIW structure. Unlike the direct optimum method, the proposed method takes shorter calculation time, and ensures the calculation accuracy. A SIW transverse mental iris filter is designed and fabricated, simulation and measurement results agree with each other well, which shows that the design method is accurate and the empirical equation is reliable.