Compact Microwave Radiator for Improving Heating Uniformity in Hyperthermia System

A compact microwave radiator is proposed for the treatment of a superficial tumor in a noninvasive hyperthermia application. The proposed radiator is designed to simplify treatment of relatively small tumors by reducing the physical size of the radiator. The proposed radiator is reduced to a size of 27.2×27.2 mm², which corresponds to 0.038 λ×0.038 λ at 433 MHz, so as to induce the optimal heating area for approximately 30-mm tumors, and is studied using a phantom as a model to analyze the thermal characteristics for the human body. The concept of effective treatment area (ETA) is defined in this letter in order to evaluate the area that can be sufficiently heated. The specific absorption rate (SAR) and temperature are uniformly formed on the phantom surface with a symmetrical and circular-shaped distribution. An ETA ratio of 91.6% is achieved for the measurements, corresponding to a 30.4-mm diameter, and the temperature increase required for tumor necrosis is achieved.