A band-pass/stop filter made of SRRs and C-SRRs

Frequency Selective Surfaces (FSS) are usually classified into two big groups depending on whether they are made of unconnected elements or connected elements. Close to their resonance frequency, the first type behaves like a band-stop filter while the second type like a band-pass filter. In this paper we propose a new type of surface made of Split Ring Resonators (SRRs) and, at the same time, Complementary Split Ring Resonators (CSRRs), placed in such a way that the surface is self-complementary. The main result is that this FSS shows band-stop features for one linear polarization state and band-pass features for the orthogonal polarization. Therefore, it is in the middle between the two usual groups of FSS, what could drive us to new designs of band-pass/stop filters which are are easily switchable from band-pass to band-stop, and viceversa, by simply rotating the surface through 90 degrees.