Tunable liquid crystal metasurface with polarization selection characteristic

Abstract

In this paper, a systematic design method for tunable metasurface based on liquid crystal (LC) is proposed, which exhibits the property of polarization selection. A compact LC-based meta-atom with a dimension of 0.12 λ × 0.12 λ is designed. The metasurface element consists of a pair of planar metallic structures, between which the LC is sandwiched. The equivalent circuit, electric field distribution, and current distribution elaborate on the design method and operating principle of the LC-based metasurface in detail. Full wave simulations show that the tunable metasurface provides bandpass and bandstop characteristics for TE and TM polarization, respectively. The center frequencies of the passband and stopband are tuned from 10.88 GHz to 10.3 GHz and 10.90 GHz to 10.18 GHz, and the tuning range reaches up to 5.5% and 6.8%, respectively. Compared with the existing work, tunability is introduced while maintaining the polarization selection characteristics. Moreover, frequency responses of the LC-based metasurface under various incident angles from 0° to 70° are kept to be stable for arbitrary LC states. In addition, a prototype sample is designed, fabricated, and measured to verify the proposed design method.