New filter topology with a reflectionless feature based on slow-wave structures loaded with resonator arrays

Abstract

We report a filter topology with reflectionless properties within the stopband. Based on a periodic-impedance coplanar waveguide (CPW) supporting slow waves and complementary split ring resonator (CSRR) arrays, a reflectionless bandstop filter is realized as an example. Energy within the stopband is dissipated in carefully arranged CSRR arrays instead of being reflected back, maintaining a well impedance match within the full frequency band. The design procedure, simulations, sample fabrication, and experiments are presented to vindicate the proposed reflectionless filter topology. It is foreseeable that based on our methodology, various wireless reflectionless filters can be designed to work from the radiofrequency to the optical band.