Compact liquid crystal based phase shifter with integrated bias tees

Abstract

Two electrically controlled tunable phase shifters based on liquid crystal (LC) material have been presented. Due to the large size and heavy weight of used external bias tees in driving circuits of LC based microwave devices, we fabricated an LC based phase shifter with integrated mini bias tees in order to broaden its potential uses. The differential phase shift up to 270°at 10 GHz was achieved in experiment under a bias voltage of 20 Vrms. For comparison, a non-integration phase shifter was also fabricated and it possesses notable performance. In the preliminary design with bias tees integrated, the mechanical layout and circuit design, as well as the soldering of the capacitors and mini bias tees were very challenging. An optimized phase shifter design with integrated mini bias tees will be shown in the near future.