Atopic Dermatitis Detection with a Compact Ku-Band CSRR-Based Sensor

This work presents a microwave-based system for monitoring superficial skin fissures, characteristic of Atopic Dermatitis (AD). The proposed solution utilizes a miniaturized Complementary Split Ring Resonator (CSRR) operating at 16 GHz, excited by a coupled open-ended microstrip line. The sensor is compact, non-invasive, and electrode-less. The high operating frequency is selected to ensure that the resonator nearfield interaction is confined to the superficial, non-vascularized skin layers, namely the stratum corneum. As a result, the resonator fringing field predominantly interacts with AD-induced skin fissures. Depending on the dimensions and severity of the damage, variations in the skin effective complex permittivity of the affected layers can be detected by monitoring changes in the system's reflection coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{11}$</tex> and E-field penetration. The novel sensor concept is designed and initially validated through electromagnetic (EM) simulations, demonstrating high sensitivity to 3-D variations in fissure characteristics. The selective interaction with superficial layers is confirmed only by analyzing the electromagnetic field distribution across them, which is corroborated by the corresponding variations in the amplitude and phase of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{11}$</tex> at the sensing interface. This approach provides a low-cost and effective solution for detecting AD-related skin damage and distinguishing between different severity levels of the condition.