High Figure of Merit Liquid Crystal Phase Shifter for <i>Ku</i>-Band

Abstract

The figure of merit (FoM) of phase shifters is important in modern satellite communication systems, and thus, a novel liquid crystal (LC) phase shifter that fulfills a high FoM property in the Ku-band is presented in this letter. The developed phase shifter is composed mainly of a central coplanar differential line, which is loaded with 46 gradual periodic LC parallel-plate variable capacitances dominated by the bias voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\mathbf {bias}}$ </tex-math></inline-formula> ). This coplanar differential line LC phase shifter (CDLCPS) is manufactured and measured to demonstrate its advantageous performance. The experimental results and the simulation results reveal good consistency. The reflection coefficient <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$S_{11}$ </tex-math></inline-formula> of the proposed design is less than −10 dB throughout the operation band from 11 to 13 GHz. At 12 GHz, the maximum insertion loss (IL) of the manufactured prototype is 3.34 dB, and the maximum phase shift value is 392°, which demonstrates an FoM equal to 117.4°/dB.