Design and Performance Measurement of Worn-on-Body Instrumental Ultra-Miniaturized UWB Wearable Patch for e-Health Monitoring

Abstract

A conformal, ultra-miniaturized, circuit integrated ultra-wideband (UWB) coplanar-waveguide (CPW) antenna system for worn-on-body applications is developed in this article. The performance study of the proposed antenna is performed over a four-layer human body tissue model. A shortened ground plane and a pair of L-shaped stubs are included to the umbrella-shaped patch configuration to enhance the impedance bandwidth between 3.15-10.55 GHz, which encompass a variety of applications like WiMAX band (3.3-3.8 GHz), WLAN band (5.150-5.350 GHz), unlicensed ISM band (5.725-5.875 GHz), and X-band (7.250-7.745, and 7.900-8.395 GHz). The realization of wideband behavior for the reported antenna is studied using the characteristic mode theory (CMT). A maximum peak gain of 4.2 dBi is achieved with maximum radiations in broadside with higher front-to-back ratio in both E-plane and H-plane. Furthermore, the robustness of the proposed antenna is evaluated by studying its performances under different conditions, such as using a coaxial feeding system, bending and assessing SAR levels. The antenna is fabricated and assembled with various circuit components to validate its performance with the simulated counterpart. The experiment is carried out by placing the antenna structure over different parts of the human body. Finally, a comparative analysis is carried out and it is found that the proposed antenna exhibits 98.2% compactness than the existing antenna designs available in the literature.