Narrow Band, Sharp Roll-Off Rejection Frequency Selective Surface Based on Substrate Integrated Waveguide

In this paper, a novel frequency selective surface which has a narrower passband and sharper rolloff rejection than the other single layer designs, is presented. Also, it has better independency from angle and polarization of incident plane wave. In this design a ring loop is placed on a cylindrical cavity of substrate integrated waveguide (SIW). Because of the most compatibility between loop and the electric fields of cylindrical cavity, minimum insertion loss and narrow passband are achieved.