SWITCHABLE SPLIT-RING FREQUENCY SELECTIVE SURFACES

A tunable frequency selective surface (FSS) based on split-ring resonators (SRRs) is presented. Tuning performance is achieved by means of several on/off switches placed between the rings of each SRR element. The band-stop FSS response is dynamically tuned to different frequency bands at different switching states. A switchable dual-layer FSS is also introduced to demonstrate a filter response over a larger frequency band. By using complementary-SRR (CSRR) elements, a tunable band-pass response instead can be obtained using a similar switching configuration. The numerical analysis of the proposed designs is accomplished using a fast periodic array simulator. In the paper, we present simulation results to demonstrate multi-frequency performance of the proposed FSS designs, namely, SRR-FSS, DSRR-FSS, and CSRR-FSS. We note that the numerical analysis of the designs is achieved by means of a well-validated periodic array simulator (7). While the switches are initially modeled as metallic pads placed along the rings at appropriate locations, the effect of equivalent circuit models of actual switches are discussed in the paper along with the scanning performance of the FSS.