Comparison study of microwave patch antennas at 434 MHz for intra cavitary hyperthermia applicator design

Targeted heating with minimal dose to neighboring tissues is possible with intra cavitary microwave applicators as they can treat tumors within/or nearby body cavities. Here we present an intra cavitary applicator for hyperthermia treatment of gynecological cancers at 434 MHz. A 3D numerical model of the applicator with conformal patch antenna in muscle tissue is studied for rectangular patch, variations of bow tie and spiral antennas. Antenna performance is evaluated in terms of size, return loss, bandwidth, specific absorption rate (SAR) and effective field surface (EFS). Fish tailed bow tie and spiral patches exhibited ≤-25 dB return loss and ≥25 MHz bandwidth compared to other shapes. EFS of spiral antenna is larger than fish tail. However, ratio of EFS to patch area indicates larger volumetric power deposition for fish tailed bow tie. From simulation results, it can be concluded that an array of fish tailed bow tie and/or spiral patch antennas would provide adjustable heating profile with high power deposition.