Design of Bandpass Filter Based on Hybrid Planar Waveguide Resonator

This paper presents a new concept of bandpass resonator based upon the association of planar and substrate integrated waveguide technologies. The selectivity, control of rejection, and ease of design are significantly enhanced by the hybrid planar waveguide resonator compared to the classical substrate integrated waveguide resonators. The hybrid planar waveguide resonator is built from the association of two elements: a substrate integrated circular cavity and a transmission line. When these two elements are connected together, they permit the occurrence of the pole and the transmission zero of the hybrid planar waveguide resonator. This paper describes and discusses the design procedure for n th-order filters. This procedure relies on an iterative process between synthesis equations and a graph. Electrical performances and particularly Q factor are brought to the fore through the realization of a single resonator. The design procedure is then validated through the realization and measurement of a C-band second-order filter. Finally, a third-order filter in the Ku -band is designed, realized, and measured.