A Gaussian-Beam Launcher for Microwave Exposure Studies

A practical method of producing a focused-microwave exposure field in biological experiments, for selective partial-body irradiation, is described. The proposed structure consists of a dielectric sphere placed in front of, but displaced from, tbe open end of a corrugated pipe with quarter-wave teeth, carrying the HEl ~ mode. It is shown that this launcher produces a near-circular Gaussian beam in the proximity of the dielectric sphere, with a high on-axis gain factor, Theoretical expressions are derived for the EM fields of the focused beam-wave, and experimental results obtained from a practical launcher confirm the theoretical calculations made.