Reconfigurable Plasma Circularly Polarized Magneto-Electric Dipole Antenna

This paper proposes a plasma based circularly polarized (CP) magneto- electric (ME) dipole antenna with reconfigurable radiation characteristic. The antenna consists of two horizontal trapezoidal plasma patches, two vertical plasma patches, and shaped metallic cavity. The antenna is fed using Gamma-shaped plasma dipole. The antenna introduces wide impedance matching bandwidth of 75 % (from 1.64 GHz to 3.7 GHz) and wide circular polarization bandwidth of 68% (from 1.9 GHz to 3.7 GHz). The operating frequency bandwidth of the ME-dipole is controlled by the plasma frequency according to its applications such as DCS/UMTS (1.71-2.18 GHz), 3G/LTE (1.84-2.69 GHz), and through-the-wall imaging radars (1.6-3.7 GHz). The radiation characteristics of the proposed ME-dipole antenna are investigated for different plasma frequencies. The antenna introduces a stable gain with peak value of 10.7 dB and high efficiency of 95%. A 2x2 ME-dipole antenna array with sequential feed is employed to improve the antenna gain and circular polarized bandwidth of the plasma ME-dipole antenna. Two array arrangements have been investigated for high gain and wideband CP characteristics.