Dimensional Synthesis of Symmetric Wideband Waveguide Cross-Coupled Filters Without Global Full-Wave Optimization

This paper presents a dimensional synthesis method for the design of symmetric wideband waveguide cross-coupled filters without resorting to global full-wave optimization. In this method, we propose two circuit models suitable for the synthesis of wideband cross-coupled filters. Besides, we propose a novel physical realization of the cross-coupled K-inverter in the waveguide filter. As a design example, an X-band four-pole waveguide cross-coupled filter has been designed and fabricated. The results show good equal-ripple performance in the passband and improved rejection performance beyond the passband.