Dual-Band Filters in Rectangular Waveguide Based on Resonant Apertures

The objective of this paper is to describe dual-band filters in rectangular waveguide based on resonant apertures. In addition, we also discuss the use of several techniques like capacitive stubs, width alteration in the resonators and staircase configurations to improve both the selectivity and the out-of-band performance of the basic filter structure. Finally, we show in detail the simulated performance of several filter configurations, thereby fully validating the new filter topology.