Investigation of the microwave controllable liquid crystal phase shifter

The design of the controllable microstrip liquid crystal phase shifter based on the photonic crystal structure is theoretically and experimentally investigated. An analytical expression relating the main parameters of the device: the controlled phase shift, the fractional bandwidth, the anisotropy of the used liquid crystal permittivity and the number of resonators is obtained. Good agreement between the calculated characteristics and the results of the numerical analysis obtained in the quasistatic approximation is shown. The results of the experimental investigation of the nine-resonator phase shifter are presented. The phase shifter is based on an irregular microstrip structure in which the nematic liquid crystal active layer is located between the screen and quartz suspended substrate. The prospects of using the developed device in the centimeter and millimeter wavelengths are shown.