A Compact Wideband Antenna Design for Biomedical In‐Body Applications

Abstract This paper presents the design, optimization, and experimental assessment of a compact ultra‐wideband (UWB) antenna tailored for on‐body biomedical applications. The proposed antenna features an eight‐pointed star‐shaped patch with a microstrip‐fed configuration and is engineered to operate effectively when placed directly on the human skin surface. The final design achieves a measured impedance bandwidth of 15.6 GHz, spanning from 6.2 to 21.8 GHz, making it suitable for a wide range of high‐data‐rate and diagnostic applications. A realistic three‐layer human tissue model—comprising skin, fat, and muscle—is employed in full‐wave simulations to evaluate the antenna's performance under practical conditions. Simulation and measurement results show that the antenna maintains good impedance matching and stable directivity across the operational band, while off‐body radiation remains minimal, confirming its near‐field operation. The antenna exhibits low realized gain (around −10 dBi) and efficiency (∼2%) due to significant absorption by lossy biological tissues, aligning with its intended function of delivering electromagnetic energy into the body for wireless sensing or in‐body communication. Specific absorption rate (SAR) analysis verifies that the antenna complies with safety standards, ensuring its suitability for wearable or implantable biomedical systems. The compact form factor, wideband performance, and robust interaction with human tissues confirm the proposed antenna's potential for advanced biomedical applications.