Characteristic Mode Analysis of Polarization Reconfigurable Compact Metasurface Antenna for sub-6GHz 5G Application

This paper presents the characteristic mode based polarization reconfigurable compact metasurface(MTS) antenna for sub 6GHz 5G applications. The MTS consists 2x2 array of rectangular unit cells arranged on the circular substrate. By rotating the antenna, three states of polarization can be achieved such as linear polarization(LP), left hand circular polarization(LHCP) and right hand circular polarization(RHCP). The MTS is excited by the slot aperture with the help of electromagnetic coupling scheme. The designed and fabricated antenna is compact
$(\mathbf{0.29}\lambda_{0}^{2})$
, which provides an impedance band-width of 19.23%(3.45GHz-4.19GHz) and axial ratio bandwidth of 5.05%(3.55GHz-3.72GHz). The peak gain of 5.2dBiC at 3.72GHz is obtained within CP bandwidth with 75% of radiation efficiency. The radiation pattern has better cross polarization values of more than -30dB with respect to co-polarization value in all the three states of polarization. This compact antenna is better suitable in sub-6GHz 5G application where switching of polarization is required without any hardware circuitry is essential.