Dual-Reject-Band Filters With Resonant Apertures in Rectangular Waveguide

This article describes a new family of dual-reject-band filters in rectangular waveguide that uses resonant apertures (RAs), and is suitable for narrow-band applications. Reject-band filters are commonly used to protect from interference in both communication and earth observation systems. The filter structure that we propose is based on a simple modification of the traditional narrow-band reject-band filter. We first describe the basic dual-reject-band filter structure, then we discuss the results of a detailed parametric analysis (all relevant data are provided in the Appendix) to be used as a basis for the filter design procedure. The design of several dual-reject-band filter prototypes is discussed in detail, including sensitivity to manufacturing errors and high-power analysis. Finally, simulations and measurements are also compared, showing very good agreement, thereby fully validating both the design procedure and the new filter topology that we propose.