A Wideband Dual-cavity-backed Polarization Reconfigurable Antenna Based on Liquid Metal Switches

This letter presents a wideband polarization reconfigurable antenna based on liquid metal (LM) switches.It consists of single-fed crossed bowtie dipoles, a parasitic element grounded via a metallic post, a dual-cavity-backed reflector, and liquid metal switches.The two arms of one dipole are loaded with two symmetrical identical slots, and on top of the slots, two sets of fixedlength movable liquid metal columns filled in polytetrafluoroethylene (PTFE) tubes are attached as switches.The altering between linear polarization (LP) and circular polarization (CP) can be achieved by changing the positions of the liquid metal switches.The dual-cavity structure is applied to obtain unidirectional radiation and enhance the circularly polarized performance.A prototype with overall size of 127 × 127 × 57 mm 3 is designed and fabricated.The measured results indicate that the impedance bandwidth (IBW) of the antenna is from 1.06 to 2.46 GHz (79.54%), and the axial ratio bandwidth (ARBW) is from 1.39 to 1.91 GHz (31.52%) for CP state.In addition, the IBW for LP state is from 1.06 to 2.30 GHz (73.81%).Moreover, the peak gains can reach 7.73 dBic in CP state and 9.21 dBi in LP state.