Metamaterial based AMC backed archimedean spiral antenna for in-vitro microwave hyperthermia of skin cancer.

This research article presents a study that uses microwave frequencies (ISM band) for treatment of skin cancer by heating the malignant cells on skin with a Microwave Hyperthermia (MWHT) applicator. The proposed MWHT applicator has been designed as an Archimedean Spiral Microstrip Patch Antenna (AMSPA) of dimensions 38 × 38 × 1.64 mm3 backed with a Meshed-shaped AMC (48 × 48 × 3.27mm3) reflector, placed at an optimized distance of 12 mm from AMSPA. The proposed AMSPA is designed as a single spiral resonator and fabricated on FR-4 substrate, excited using a feed network. The proposed AMSPA shows a resonance at 2.5 GHz with an impedance BW of 260 MHz (2.37-2.63 GHz) and peak gain of 3.20 dB with a bidirectional radiation pattern. An AMC is placed at its backside that can be exploited as a phase-compensation surface to attain an in-phase profile for directive emission and improve the BW upto 470 MHz, peak gain to 6.8 dB and also enhance the front-to-back ratio of the radiating antenna with radiation efficiency of 80%. The simulated environment for hyperthermia analysis is set up using penne's Bio-Heat equations to deliver microwave energy to the bio-mimic, that leads to a rise in temperature over the designed bio-mimic in CST MWS in the range of 41-45°C. The validation of MWHT radiation properties and temperature rise inside the malignancy of phantom is carried out by fabricating the bio-mimic using gelatine, vegetable oils and glycerol. This set up enhances the penetration-depth of EM waves inside the tri-layered phantom up-to 29.5 mm with Effective Field Surface of 36 × 36 mm2 and SAR of 8 W/Kg.