A systematic approach towards realization of transmission zeros in TE 01δ mode dielectric resonator filters with all iris couplings

Abstract

This paper presents a novel method using a coupling matrix to realize dielectric resonator filters with Transmission Zeros (TZs). This method eliminates the necessity of capacitive coupling in conventional DR filter designs with TZs. Using the proposed technique, the cross-coupling sign can be changed systematically while the amplitude frequency response is kept unchanged. The method is independent of the filter physical structure and all design steps are based on coupling matrix equation and models. Therefore, unlike the extracted pole technique, this method not only does not require time consuming optimization in full wave simulations but also the extra resonator in this method helps in improving the group delay performance of the filter. After presenting the method, the calculated coupling matrix for a 7 × 4 DR filter will be realized using TE01δ mode of cylindrical dielectric resonators and simulation and measurement results will be compared.