Liquid Crystal-Based Polarization Reconfigurable Cross-Slot Fed Patch Antenna

A liquid crystal (LC)-based polarization reconfigurable cross-slot fed patch antenna is presented in this paper. The LC-based antenna is designed to operate at around 27.6 GHz. The antenna includes four perpendicular patches which are fed by a cross slot. By controlling LC permittivities under these patches, the different resonance frequencies can be obtained. Based on the degenerate mode theory, the frequency shift of the perpendicular patches generates the phase difference of 90°, and then the circular polarization will be achieved. When resonance frequencies of the patches are the same, linear polarization will be obtained. The simulated results shows that the LC-based antenna can have the left/right-hand circular polarization, and linear polarization switchable functionality.