Focused Array Hyperthermia Applicator: Theory and Experiment

The design and analysis of a focused linear array at 2450 MHz for microwave hyperthermia research is described. The array, which was submerged in deionized water to reduce its size and to provide a better impedance match to a high dielectric medium representative of human tissues, consisted of four titanium dioxide loaded horn antennas with apertures of 2.0 x 1.4 cm and a feed network with weighted phase shifts, Power radiation pattern measurements were made in planes ranging from 7.6 to 10.2 cm from the array to determine the focusing characteristics and beam spot size. Due to high attenuation in the medium, planes beyond 10.2 cm were not considered. The half-power beamwidth (HPBW) measured at the focal point was approximately 1.3 cm. The measured patterns were found to be in close agreement with theoretical predictions.