A Simple Frequency- and Polarization-Reconfigurable Bent Monopole Antenna Based on Liquid Metal

In this letter, a frequency- and polarization-reconfigurable bent monopole antenna using liquid metal is proposed. The proposed antenna is designed to operate at continuously tunable frequencies and switch between left-handed circular polarization (LHCP) and right-handed circular polarization (RHCP) states. The frequency reconfigurability is achieved by controlling the length of the liquid metal to change the electrical length of the antenna. The circularly polarization can be achieved by injecting from the inlet, and excited by orthogonal horizontal radiation as well as vertical radiation. 3 dB axial ratio bandwidth of 37.5%(3.12–4.63 GHz) in LHCP state and 48.8% (3.07–5.05 GHz) in RHCP state can be achieved. The whole antenna is characterized by continuous tunability, reconfigurable frequency and polarization, and wide tunable bandwidth. The measured results of constructed prototypes are in close agreement with the simulation results, and its feasibility is fully proved.