Antenna radiation properties in presence of anisotropic plasmas

An extensive quantitative experimental investigation was conducted on the influence of a magnetic field on the radiation from a horn antenna situated behind a layer or sheath of plasma. The magnetic field direction in the experiments was along the principal direction of radiation of the antenna which is normal to the layer of plasma. The experimental results were compared with theory based on the reciprocity theorem. For the left circularly polarized wave radiation pattern, propagation effects at off-normal incidence corresponding to the condition for which the ordinary wave mode switches to the extraordinary wave mode as the electron density passes through the critical density are shown to be of importance. For the right circularly polarized wave mode, significant departures in the measured radiation pattern from the theoretical occur in the region of the electron cyclotron frequency and below. Satisfactory correspondence between theory and experiment is found for values of the electron cyclotron frequency that are greater than the wave frequency.