Development and Optimization of a Geometrically Simplified Microstrip Patch Antenna for Biomedical Applications

This paper presents a microstrip patch antenna intended for biomedical use, characterized by a simple structure. The patch antenna is effectively designed to resonate at frequencies typical of the Industrial, Scientific, and Medical (ISM) bands, namely 2.45 GHz and 5.8 GHz. Notably, resonance is also achieved at 4.59 GHz, slightly outside the ISM range. Constructed with FR4 material, the antenna measures <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{48}\mathbf{mm}\times \mathbf{48}\mathbf{mm}\times \mathbf{1.6}\mathbf{mm}$</tex> and showcases a distinctive patch design. Performance evaluation reveals impressive return loss figures of approximately -36.87 dB, -30.08 dB, and -42.51 dB across frequency bands (2.39-2.49) GHz, (4.34-4.70) GHz, and (5.76-5.96) GHz respectively. Peak gain values at these resonant frequencies are measured at 2.54 dBi, 1.16 dBi, and 1.72 dBi. In consideration of biomedical applications, specific absorption rates (SAR) remain below 1.6 W/kg, with values recorded at 1.08 W/kg for 2.45 GHz and 0.96 W/kg for 5.8 GHz. Both simulation and experimental outcomes along with a comparison with the existing design affirm the antenna's suitability for biomedical applications, aligning with established safety standards.