CPW-fed ultra-wideband slot antenna with broadband dual circular polarization

Abstract

A novel coplanar waveguide (CPW) fed ultra-wideband slot antenna with broadband dual circular polarization is proposed, fabricated and measured. The antenna structure is simple and consists of two CPW-fed ports to achieve both right-hand circular polarization and left-hand circular polarization at the same frequency band with the overall size of 48 × 48 × 1 mm3. The design process of the proposed antenna is given and the circular polarization mechanism is analyzed from the surface current distribution. The variation of return loss, port isolation and axial ratio (AR) with antenna parameters is simulated. By optimizing the radiation patch and improving the ground plane, the ultra wide impedance bandwidth and broad axial ratio bandwidth are achieved. The measured impedance bandwidth is 153.1% (1.9–14.3 GHz) with return loss better than 10 dB, and the measured 3 dB axial ratio bandwidth is 102.6% (1.9–5.9 GHz). The gain and port isolation are better than 3 dB and 15 dB, respectively, within the AR band.