Narrow-beam antennas using cylindrical columns of isotropic plasma

Abstract

It has been reported earlier (Gupta 1970) that a radiation pattern with single or multiple narrow beams may be obtained when a column of isotropic plasma is excited by a ring source of electromagnetic waves placed inside the column. This investigation has been extended to the case where the waves on plasma column are excited by a waveguide source. Also the TE- and TM-modes of propagation for both the excitation schemes have been discussed. Narrow beams of radiation may be obtained in all these four eases. It is observed that the small beamwidths (1° to 5° ) are obtained for high plasma densities (ε_p = 01) and large plasma column radii (k₀b≥15.0).