This thesis provides design approaches for waveguide filter with prescribed transmission zeros. The emphasis is on a new class of filter, developed in recent years by utilizing non-resonating nodes (NRNs). First, a novel circuit model of the coupling irises of waveguide filters is developed in order to aid the design of waveguide filters with NRNs for relatively wide band applications. Also, analytical solutions of the circuit parameters are presented and verified by experimental design. Secondly, based on this new circuit model, a systematic approach for the design of filters with NRNs is developed and illustrated with two filters. The first has intermediate fractional bandwidth of 3.5%; Good results are obtained without performing global optimization. The second has a relatively wide fractional bandwidth of 8.33% and good results are achieved with very limited global optimization. The results are verified by EM simulations. Furthermore, for choosing an empty waveguide to realize the NRNs, some novel criteria are proposed to improve the spurious free window of the filter.

This thesis provides design approaches for waveguide filter with prescribed transmission zeros. The emphasis is on a new class of filter, developed in recent years by utilizing non-resonating nodes (NRNs). First, a novel circuit model of the coupling irises of waveguide filters is developed in order to aid the design of waveguide filters with NRNs for relatively wide band applications. Also, analytical solutions of the circuit parameters are presented and verified by experimental design. Secondly, based on this new circuit model, a systematic approach for the design of filters with NRNs is developed and illustrated with two filters. The first has intermediate fractional bandwidth of 3.5%; Good results are obtained without performing global optimization. The second has a relatively wide fractional bandwidth of 8.33% and good results are achieved with very limited global optimization. The results are verified by EM simulations. Furthermore, for choosing an empty waveguide to realize the NRNs, some novel criteria are proposed to improve the spurious free window of the filter.