A circular-shaped two-slot foam-based flexible UWB antenna for medical applications

The biomedical industries have recently shown a great deal of interest in the study of flexible wireless devices. Wearable antennas are vital in medical applications as they enable continuous, real-time monitoring of patient health. In this context, a circular-shaped two-slot flexible ultra-wideband microstrip antenna is presented for use in the medical field. An inexpensive, lightweight flexible foam substrate material of 2 mm thickness with dielectric constant 1.07 and copper foil of 50 microns for patch is proposed in the fabrication of antenna. This paper presents a circularly shaped antenna of size 48x36mm2\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$48\times 36 {\text{mm}}<^>{2}$$\end{document} with patch radius of 12 mm and detailed analysis of bending, on-body and SAR with actual measurement. A good matching is observed between measured and simulated results with the bandwidth of 10 GHz over the ultra-wideband operating frequencies of 3.1-10.7 GHz. The slot and stub added into geometry has resulted into the total gain of 4.7 dB, with good impedance matching. An extensive SAR analysis for 1 and 10 g tissue has been carried out with average SAR of 0.0215 W/kg and 0.0138 W/kg respectively and found below the safety limit as prescribed by IEEE.