A Multigap Loop Antenna With Phased Excitation in a Magnetoplasma

Electrodynamic characteristics of a multigap loop antenna immersed in a homogeneous magnetoplasma are studied using the integral equation method. The antenna has the form of a perfectly conducting, infinitesimally thin, narrow strip coiled into a ring with its axis parallel to an external static magnetic field. The antenna current is excited by appropriately phased external voltages applied across the gaps of the strip. A closed-form solution for the current distribution of the antenna is obtained, and the elements of its input admittance matrix are found. Based on this solution, conditions are determined under which such an antenna with phased excitation is capable of selectively exciting waves with given azimuthal indices in the surrounding magnetoplasma.