Refinement of a Microwave Needle Applicator for Cancer Therapy via Metamaterials

The insertion of a metamaterial (MTM) lens based on Closed Loop Resonator (CLR) into a needle microwave applicator is investigated for a more efficient hyperthermia cancer therapy. Several geometries are designed and optimized, Closed Circular-Ring Resonator (CCRR) with circular loops and Closed Square-Ring Resonator (CSRR) with square loops, with one or more concentric loops. The MTM lens is bended around to the radiating section of the antenna to form a cylindrical 3D structure. Preliminary investigations have been focused to increase the device feasibility and patient wellness. The applicator is a slot coaxial antenna inserted into a surgical needle of 16 G and operating around at the center of Industrial, Scientific, and Medical (ISM) frequency band. The experimental results pertaining to a preliminary fabricated prototype of needle applicator are encouraging, and the simulation results suggest that they could be improved by using the investigated MTM lens.