Frequency and Polarization Transformer (10 GHz to 1000 GHz): Interaction of a Whistler Wave With a Collapsing Plasma in a Cavity

This paper investigates the interaction of an electromagnetic wave with a time-varying (collapsing) magnetoplasma medium. Finite-difference time-domain techniques are used to evaluate the effects of collapsing a magnetized plasma in a perfect electric conductor cavity. The evaluation is performed in one dimension to simplify the analysis and highlight the effects on propagation due to the time-varying plasma parameters. The interaction of an electromagnetic wave with a time-varying medium is governed by the property of conservation of the wavenumber. This property can be utilized to construct a frequency transformer. It is shown that switching off the ionization source and creating a decaying magnetoplasma medium in a cavity will upshift the source frequency of 10-1000 GHz for the appropriate choice of initial magnetoplasma parameters. The electric field of the output wave is comparable with that of the source wave. Moreover, the switching angle can alter the polarization of the output wave.