Nonlinear gain of a dipole antenna immersed in a collisionless plasma

This paper presents an investigation of the effect of collisionless plasma on the equatorial gain of a high power dipole antenna. The plasma experiences a ponderomotive force in the non-uniform radiation field and the electron density gets redistributed; the plasma gets depleted in the centre and the near equatorial zone of the antenna. This nonuniformity in the electron density (hence in the dielectric constant) tends to converge the electromagnetic power to the equatorial zone. For typical parameters a 20% (i.e., ∼1 dB) enhancement in the gain of the antenna has been predicted within the limits of the perturbation theory. Work partially supported by NSF (USA)