Design a metamaterial based applicator for hyperthermia cancer treatment

This research describes a metamaterial-based applicator with and without water bolus for cancer treatment. The metamaterial based applicator consists of a double spiral antenna and a slotted square shape artificial magnetic conductor (SSA) structure. The antenna is designed on a low-cost FR4 substrate with dimensions of 32 x 32 x 3.27 mm(,)(3) and the SSA unit cell which behaves as a metamaterial, is designed on an RT-duroid substrate with dimensions of 15 x 15 x 0.76 mm(3) (size of the unit cell). The 4 x 4 unit cells of the SSA structure are optimized to direct the maximum field toward the cancer tissue. The proposed applicator (antenna + SSA structure) is tested for hyperthermia treatment using a heterogeneous phantom (skin, fat, and muscle layers) and the human-mimicked model with an air medium and a water bolus layer. The applicator's performance is evaluated in terms of specific absorption rate (SAR), penetration depth (PD), and effective field size (EFS). Further, thermal analysis is performed, with 1.5 W of input power at the antenna port, and the maximum temperature rise of 44 C-0 is obtained. The cancer tissue (tumor) temperature ranges between 41 degrees C to 45 degrees C, sufficient for effective hyperthermia therapy. Finally, the suggested metamaterial based applicator is built and tested in the presence of a phantom and head tissue simulating liquid.