Amplitude modulation of microwaves propagated through a periodically varying plasma

Abstract

A theory has been developed for the amplitude modulation of microwave signals propagated through a plasma created by an amplitude modulated RF field by taking into account the variations in the electron density and the electron molecule collision frequency of the plasma due to the modulation of the electron temperature. Experimental studies have verified the predicted dependence of the microwave modulation index on the modulation frequency, the exciting field strength, and the carrier modulation index. Slight deviations have been found between the experimental and theoretical values at both very low and very high modulation frequencies. The dependence of the RF conductivity on the exciting field has been suggested as the probable cause for the departures of the experimental values from the theoretical ones.