Dual Mode Split Ring Resonator Sensing and Hyperthermia Array for Skin

We present a dual mode, high sensitivity and low-cost applicator array based on split ring resonators (SRR) and microstrip coupled lines, serving as both an imaging and treatment tool for skin cancers. The applicator array consists of 3x3 unit cells, in which each unit in a row is tuned to a separate frequency, ranging from 8 to 15 GHz (unloaded). The via fences surrounding the unit cells provide E-field shielding and enhance resonance. A prototype applicator array is realized on multi-layer FR-4 substrate. The excitation is coupled magnetically from microstrip to SRRs and generates strong E-fields across the gap between SRR loop terminals. By observing the resonance shift and attenuation under different material under test (MUT), skin in our case, permittivity differences can be analyzed to distinguish malignancies from healthy tissue. Using the same applicator array, we further demonstrate hyperthermia capability requiring only 5 w of power to cause significant temperature elevation.