Surface-Wave Estimate of Skin Tissue Permittivity

Microwave technologies have recently attracted attention as a viable tool for skin cancer diagnoses. In the research thereof, tissue characterization is essential. The commonly used dielectric probes are an evolved and advanced tool, which relies on electromagnetic wave reflection. Surface waves, researched in this work, hold promise for the design of low-profile sensing elements. We propose a theoretical model in this study that measures permittivity contrasts between tissues by analyzing the phase shift between two sensors. Simulations conducted using two patch antennas as sensors produced encouraging results, accurately estimating the permittivity contrasts across three models. The experimental validation utilized two oil-gelatin skin phantoms, and the estimated permittivity contrasts align well with the true values. We report results that encourage us to explore microwave-range surface waves further towards a non-invasive dielectric characterization of the skin tissues.