Ab initio analysis of frequency selective surfaces based on conventional and complementary split ring resonators

Frequency selective surfaces (FSSs) made up of periodic arrays of split ring resonators (SRRs) are analysed. This analysis includes complementary screens, or complementary SRR-FSSs (CSRR-FSSs). It is shown that these FSSs show a dual behaviour, with a stop/pass band behaviour at the frequency of resonance of the SRRs/CSRRs. Cross-polarization effects in the SRR and the CSRR are considered, and it is shown that they permit resonance to occur for normally incident plane wave excitation. This latter property of SRRs and CSRRs also implies that the FSSs considered may act as polarizers and polarization converters as well. An analytical theory, valid for perfectly conducting and infinitely thin screens, is proposed for the SRR-FSSs and CSRR-FSSs. These approximations are valid in the microwave and millimetre-wave range, and up to the terahertz range.