Sequentially Rotated-Fed Patch Array Antenna for Off-Body Communication

This work presents a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2 \times 2$</tex> sequentially rotated patch antenna array designed for a body-area network (BAN) biotelemetry system operating in the unlicensed 5.8 GHz band. Circular polarization is achieved by truncating two diagonally opposite corners of the square patches, which excites two orthogonal modes within the antenna. This design enables the generation of circularly polarized radiation. A prototype of the antenna array was fabricated and experimentally validated, demonstrating strong agreement between simulated and measured results in terms of impedance bandwidth, axial ratio, gain, and radiation characteristics. With its compact and low-profile design, the proposed antenna is well-suited for wearable devices operating in the ISM band.