Polarization Reconfigurable Filtering Patch Antenna Using Liquid Metal

A novel polarization reconfigurable filtering antenna is introduced in this paper. The antenna has the characteristics of independent adjustment of polarization mode and filtering transmission zeros (TZ), good passband gain flatness and so on. The bottom layer of the antenna is coupled with the upper radiation patch through the microstrip branch structure to form a filtering antenna with three TZ. The filtering antenna loads the polydimethylsiloxane (PDMS) structure onto the microstrip branch feeding structure, controls the length of liquid metal (LM) in three 3D printing slots, and realizes the switching between left-hand circular polarization (LHCP), right-hand circular polarization (RHCP) and linear polarization (LP). The circular polarization axial ratio (AR) bandwidth can reach 4% and 3.7% respectively, and the gain is 4.6dBi and 4.5 dBi. The antenna has a 17% (3.37~4 GHz) 10 dB impedance band and a peak gain of 4.7 dBi in the passband.