Wideband Polarization-Reconfigurable Monopole Antenna Using Electrical- and Thermal-Switchable Chips Based on Phase Change Material Germanium Telluride

In this letter, a coplanar waveguide-fed wideband polarization-reconfigurable monopole antenna utilizing chalcogenide germanium telluride (GeTe) is proposed. The main radiation part is a rectangular loop, which is split into several symmetrical pieces. The adjacent pieces and ground plane are electrically connected by inverted GeTe chips. By electrical and thermal hybrid excitation, the states of all GeTe chips can be controlled to realize polarization reconfigurability. Additionally, two symmetrical parasitic elements are adopted to improve the impedance bandwidth and axial-ratio bandwidth. Finally, a simple, compact, and low-profile antenna prototype with zero static power is fabricated and tested. The measured results show that the proposed polarization-reconfigurable monopole antenna obtains a wide overlapped bandwidth of 35.7% from 2.62 GHz to 3.76 GHz for linear polarization, left-hand circular polarization, and right-hand circular polarization, which covers sub-6G and WiMAX frequency bands.