PIFA Sensor for Blood Clotting Detection

Abstract

This paper presents a dual-band printed inverted-F antenna (PIFA) designed as a biomedical sensor for detecting blood clots in lower limbs. The proposed sensor utilizes the ROGERS RO4003C substrate, chosen for its flexibility, and operates at resonant frequencies of 2.28 GHz and 5.88 GHz, with a compact size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$35\times 30\ \text{mm}^{2}$</tex>. The primary resonance is attributed to the inverted-F structure of the PIFA, while the secondary resonance arises from the meandered configuration of the PIFA's open arm. Simulation studies are conducted with a leg phantom model that simulates the lower leg structure. Additionally, the sensor's functionality is assessed on freshly cut and corrugated liver tissues to replicate clot formation. The specific absorption rate (SAR) of the sensor is also simulated and measured to ensure safe usage. Analysis of the sensor's reflection coefficient shows significant differences between normal and clotted blood conditions, confirming its potential for reliable clot detection in the specified frequency bands.