DIAGONALLY ASYMMETRIC CSRRS LOADED CIRCULARLY POLARIZED ANTENNA WITH FREQUENCY SELECTIVE SURFACE

This paper presents a compact single feed circularly polarized (CP) antenna along with a frequency selective surface (FSS) that acts as a partially reflective surface over the patch. Patch is loaded with four diagonally asymmetric complementary split ring resonators (CSRRs) in order to achieve circular polarization. In this paper a novel design of reflective type FSS layer is presented at 2.4 GHz. The size of FSS unit cell is approximately 0.132λ0 × 0.132λ0, and it is placed at a distance of 0.146λ0 from the patch. Simulated impedance bandwidth of the antenna for S11 < −10 dB is from 2.385 to 2.506 GHz (121 MHz or 4.95%) which covers the entire IEEE 802.11 WLAN band (2.4–2.484 GHz). Position of the four CSRRs on the patch and the height of FSS screen are determined through parametric studies, and the detailed analyses in terms of reflection coefficient, axial ratio, and gain variation are also presented. Gain of the antenna is 3.02 dBic at the operating frequency 2.45 GHz. Measured results are in good agreement with the simulated ones.