Compact tunable Ka-band phase shifter based on liquid crystals

Abstract

This paper presents the design and realization of a compact phase shifter based on a tunable dual-mode ring filter at 35 GHz. The tunability is achieved by employing a thin liquid crystal layer as a tunable dielectric substrate. By applying a bias voltage in the range of 0... 40V, a tunable phase range of 117° is measured. The figure of merit of the realized phase shifter is 30.6°/dB at 34.3 GHz.