Spurious Response Suppression in Waveguide Filters using E-Shaped Chiral Resonators

In this paper, chiral E-shaped resonators are used in a waveguide. Direction of EM wave and position of resonators for effective excitation is studied and various resonances of E-shaped resonators are determined. As a consequence an analytical equivalent circuit model is proposed. Finally, an array of these resonators is used to realize a wide reject band. The resulted band stop filter performance is simulated and a rejection level of almost 40 dB is achieved to confirm the effectiveness of the idea. This stopband filter is used in cascade with a bandpass filter to suppress its spurious response.