An Ultra-Wideband Circularly Polarized Multiple-Input Multiple-Output Antenna with Polarization Diversity

This paper presents an ultra-wideband (UWB) circularly polarized (CP) multiple-input multiple-output (MIMO) antenna with polarization diversity. The proposed antenna is comprised of a coplanar waveguide feed with modified geometry of the coplanar ground plane. One antenna is design with right-hand CP (RHCP) by altering only the geometry of the left-hand side coplanar ground plane. To achieve the left-hand circular polarization (LHCP) the position of the coplanar ground planes is switched. For polarization diversity, the two antennas are placed in parallel configuration. From the simulated results it is seen that the antenna yields 85% impedance bandwidth from 2.9 GHz to 7.2 GHz. The axial ratio (AR) bandwidth of the antenna is 70% from 3.06 GHz to 6.4 GHz. The peak envelop correlation coefficient (ECC) of the antenna is 0.003 when the separation between the two antennas is 0.29 λ
_o.
Moreover, the diversity gain of the antenna is approximately 9.99 dB.