Dual Circularly-Polarized Spidron Fractal Slot Antenna

Abstract

A shared-aperture dual circularly-polarized Spidron fractal slot antenna is presented. The proposed antenna, which includes a Spidron fractal slot with an L-shaped slit and a cutting corner, is fed by two individual excitation ports. The left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) at the same operating frequency band are simultaneously achieved using the even and odd modes in a coplanar waveguide transmission line. The measured –10 dB reflection and 3 dB axial ratio (AR) bandwidths are 20.24% and 8.0% for LHCP and 10.09% and 9.15% for RHCP. An average isolation of about –19.84 dB is obtained between the two ports within the overlapped bandwidth (–10 dB reflection and 3 dB AR bandwidths). The measured peak gains of the proposed antenna for LHCP and RHCP are 5.41 dBic and 3.39 dBic, respectively.