Enhanced waveguide bandpass filters using S-shaped resonators

Abstract

This article presents a new solution for stopband performance improvement of rectangular waveguide bandpass filters using S-shaped resonator loaded waveguide configurations at microwave and millimeter-wave frequencies. The proposed filter structure is compact in size when comparing with the standard E-plane counterpart. Compactness is achieved by taking advantage of the properties of slow wave effect in half wavelength resonators. Periodicity is readily imposed upon cascading the S-shaped resonators within the rectangular waveguide. The structure is simple and compatible with E-plane technology. This type of bandpass filters can be easily realized with a single metallo-dielectric insert within a standard rectangular waveguide. Simulation and experimental results are presented to validate the argument along with some design guidelines.