A Novel Frequency Beam Steering Coaxial-Slot Applicator Using Matched Load for Interstitial Breast Cancer Hyperthermia

The structure optimization is used for a coaxial slot antenna and a novel method for designing breast cancer hyperthermia applicator, using conventional semi-rigid coaxial cable is presented. The antenna radiation pattern was extracted by changing the structure of the antenna and by deploying a matched load, instead of short circuit, at the end of the antenna in order to make the applicator as a traveling wave antenna. Placing a matched load at the end of the antenna allows us to steer the radiation pattern by changing the frequency of the antenna. The radiation pattern was optimized by changing the length and position of both circumferential slots to localize the heat distribution around the applicator. The heat distribution around the tip of the antenna was then simulated using a specific absorption rate (SAR), using CST software. In addition to improving the scattering parameter S11 at 2.45 GHz, the distance of both slots from the tip of the antenna was also decreased, which in turn reduced the penetration depth of the antenna into breast tissue. The simulation results revealed that the SAR distribution improved and that the applicator can be used for breast cancer interstitial hyperthermia.