Enhanced Waveguide Bandpass Filters Using S-Shaped Resonators
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. (C) 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE 19: 627-633, 2009.
waveguide bandpass filters s-shaped resonators rectangular waveguides periodic structures