Liquid Crystal Based Ku-band Tunable Frequency Selective Surface Design

Based on the tunable liquid crystal material, this paper presents a design of tunable frequency selective surface (FSS) structure controlled by external bias voltage. The design is realized by cascading two two-dimensional hexagonal complementary open-ended harmonic periodic arrays and a hexagon resonant ring array. The proposed structure composed of three metal, four dielectric and two liquid crystal layers acts as a spatial microwave band-pass filter with high selective performance. The predicted FSS has the advantages of high frequency selectivity, stability at different incident angles and frequency tunability in Ku band. The simulation results verify the tuning performance of FSS, and the relative continuous frequency tunable range is up to 5%.