Parasitic circular patch antenna with continuously tunable linear polarization using liquid metal alloy

This article presents a center-feed parasitic circular patch antenna with continuously tuning linear polarization performance. Eutectic gallium-indium liquid metal alloy is employed to tune the angle of linear polarization continuously. The antenna is feed at the center of a circular patch with a ring slot. The rotational symmetry of the antenna helps maintain the impedance and radiation pattern at different polarization angles. The liquid metal is contained in a 1 × 1 mm channel etched in a polymethyl methacrylate cylinder. The polarization angle is tuned by controlling the location of a short bar of EGaln. The center resonant frequency of the demonstrated antenna is 5.19 GHz with a −10 dB impedance bandwidth of 0.24 GHz.