A quasi-optical phase shifter based on an active grating for the 8-mm wavelength range

A new quasi-optical phase shifter for the 8-mm wavelength range, which allows the phase of electromagnetic radiation in a wave beam to be controlled, is described. The phase shifter operation is based on the phenomenon of wave phase variation upon reflection from an active grating that is formed by the layers of plasma in channels of a dielectric plate arranged above a flat metal mirror. It is shown that the phase of the reflected wave can be effectively controlled by changing the grating-mirror distance and the gas pressure in the channels. The experimental data are compared to the results of numerical calculations.