Dielectric-loaded lens applicator for microwave hyperthermia

The authors describe a lens applicator which can concentrate the E-plane field in a lossy medium and is constructed of an easily fabricated, dielectric-filled waveguide. Since the microwave field distribution on the aperture can be varied by using different sizes of dielectric material, the heating pattern inside the medium can be changed, allowing the configuration of a compact applicator that can heat portions deeper within the human body. Heating experiments on a model simulating human muscle have shown that an applicator with an aperture of 150*100 mm² achieves a maximum heating depth of over 80 mm, results that are compatible with the deep, localized heating required by hyperthermia.