Enhanced Performance Of CPW-Fed Circularly Polarized MIMO Antenna

The circularly polarized MIMO(multiple input multiple output ) antenna is used to improve the bandwidth.The antenna is based on coplanar waveguide (CPW)-fed monopole extension of an microstrip line. The orthogonal field components required by circular polarization are induced by using a modified left/right side ground plane. In specific, a stub extending from the ground plane along with the length of the microstrip line is vertical component and the current along the width of the ground plane is horizontal component. A coplanar waveguide feeding is used with asymmetrical ground planes along the longitudinal axis of the microstrip line. One side of the ground plane is etched to create a loop-like path for the current flow. The proposed MIMO antenna features |S11| ≤ 10 dB and |S21| ≤ 22 dB from 5.1 GHz to 6.4 GHz. The antenna can operate in either uni-directional or bi-directional characteristics. It also includes multiple commerical application band like WLAN,ISM higher bands and U-NII bands.