Miniaturized Circularly Polarized UWB Antenna for Body Centric Communication

Abstract

A compact body-worn circular polarized textile monopole antenna for wearable applications is reported. The proposed antenna is fabricated on a jean fabric providing flexibility, lightweight, and easy integration into human clothes. The overall size of the proposed antenna is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$25\times 30\times1.4$ </tex-math></inline-formula> mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> . Circular polarization (CP) is advantageous for on-body communication as it provides features, such as multipath immunity, suppressing interferences, and enables better link connectivity between the sensor nodes. The proposed antenna achieves the CP using an asymmetric stepped L-shaped ground plane and through the incorporation of a cross-shaped stub in the radiator. The single-fed octagonal strip monopole antenna provides good impedance matching over the entire ultrawide frequency range from 3.09 to 11 GHz. Simulation results are in good correlation with the measured results. The axial ratio bandwidth <3 dB is achieved in the frequency range of 3.4–10 GHz. Gain and efficiency obtained are about 2.3-4.4 dBi and 65%–82% at the said frequency range, respectively. Structural deformation is performed to analyze the flexibility of the proposed antenna. The simulated SAR values follow the FCC limit making it most suitable for wearable applications.