A Novel Dual-Band Circularly Polarized Rectangular Slot Antenna

Abstract

A coplanar waveguide fed dual-band circularly polarized rectangular slot antenna is presented. The proposed antenna consists of a rectangular metal frame acting as a ground and an S-shaped monopole as a radiator. The spatial distribution of the surface current density is employed to demonstrate that the circular polarization is generated by the S-shaped monopole which controls the path of the surface currents. An antenna prototype, having overall dimension 37 × 37 × 1 mm3, has been fabricated on FR4 substrate with dielectric constant 4.4. The proposed antenna achieves 10 dB return loss bandwidths and 3 dB axial ratio (AR) in the frequency bands 2.39–2.81 GHz and 5.42–5.92 GHz, respectively. Both these characteristics are suitable for WLAN and WiMAX applications.