A Wideband Polarization-Reconfigurable Orthogonal-Dipole Antenna Controlled by Liquid Metal Switches

This letter proposes a novel wideband crossed-dipole antenna that utilizes liquid metal switches for polarization reconfiguration. The antenna consists of a wideband single-fed crossed bowtie dipole with each arm featuring a gradually varying width bent slot. A back cavity structure serves as a reflector to achieve directional radiation and circular polarization (CP) bandwidth enhancement. The proposed antenna uses movable liquid metal columns in microchannels as coupling switches to open or close the slots. By controlling the switches to close either the vertical or horizontal slots, the antenna achieves directional radiation of left-hand circular polarization or right-hand circular polarization, respectively. When all the slots are opened or closed simultaneously, the directional radiation of linear polarization (LP) is achieved. Experimental results indicate that the antenna has an impedance bandwidth (IBW) of 65.02% and an axial ratio bandwidth of 43.14% in the CP mode, with a maximum gain of 11.6 dBic. In the LP mode, the antenna exhibits an IBW of 42.5% and a maximum gain of 11.48 dBi. These results demonstrate the proposed antenna's versatility and potential for use in mobile communication terminals.