Liquid-Metal-Enabled Multi-Polarization Reconfigurable Antenna

This paper presents an antenna that can reconfigure its polarization between four different states, namely: horizontal polarization, vertical polarization, left-hand circular polarization, and right-hand circular polarization. The driving element of the antenna is a microstrip patch incorporating two feed points. It is surrounded by four parasitic elements used to improve the realized gain. Different from most of the previous polarization reconfigurable antennas, the reconfiguration is achieved by a liquid-metal-based reconfigurable feeding network, without perturbing the radiation element itself. A 3.5 GHz quad-polarization antenna has been designed, fabricated and measured. The simulation and measurement results are in excellent agreement. The measured peak realized gain of the single radiating element is approximately 9.9 dBic. The measured axial ratio (AR) associated with the right-hand circular polarization state is 1.2 dB.