Frequency-reconfigurable liquid crystal metasurface array

In this paper, a frequency-reconfigurable metasurface (MS) circularly polarized antenna array (CPAA) based on liquid crystal (LC) is presented. The antenna features a multilayer structure. Design of the MS circularly polarized antenna unit using the characteristic mode analysis method, the combination of MS structure, temperature-controlled LC, and sequential feed network not only enhances the impedance bandwidth (IBW), axial ratio bandwidth (ARBW), and gain. By adjusting the temperature to change the relative dielectric constant of the LC, further frequency reconfigurability of the CPAA is achieved. Under different temperature control settings, the effective IBW and ARBW of the antenna can be shifted from 39.0% (4.51–6.70 GHz) to 40.3% (4.61–6.94 GHz), while the peak gain moves from 11.59 dBi at 5.31 GHz to 11.71 dBi at 5.41 GHz. The results demonstrate that the proposed MS CPAA offers advantages of wide bandwidth, high gain, low profile, and frequency reconfigurability.