Analysis and Design of Dual-Band Folded-Shorted Patch Antennas for Robust Wearable Applications

Rahil Joshi,Ping Jack Soh,Symon K Podilchak,Muhammad Nazrin Ramli,Dimitris E Anagnostou,Herwansyah Lago,Constantin Constantinides

doi:10.1109/ojap.2020.2991343

Abstract

A flexible folded-shorted patch (FSP) antenna with dual-band functionality for wearable applications is presented. The proposed antenna is operational at 400 MHz and 2.4 GHz and can be considered compact for the lower operational frequency band ( $0.13\lambda _{o} \times 0.13\lambda _{o} \times 0.02\lambda _{o}$ ). Flexible polydimethylsiloxane (PDMS) is used as the substrate due to its relatively low-cost as well as its robustness for wearable applications. A comparison of the fields radiated by the FSP, in terms of the $TM_{010}$ and $TM_{001}$ modes are also presented considering the cavity model which is actually related to the two noted operating bands. Equations needed to calculate the beam pattern and directivity for these modes are also derived and their results are compared to commercial full-wave simulations and measurements of a wearable PDMS prototype. An analysis was also performed to characterize the relevant dimensions that are important for independently controlling or tuning the resonant frequencies for these two radiating modes. The proposed antenna can be suitable for robust wearable applications such as military search and rescue operations, emergency response team units, and medical services.

Highlights

W EARABLE antennas in recent years have advanced significantly and been researched for various applications
Preliminary results were reported by the authors in [25] for a simple and single-layer circularly polarized (CP) patch antenna where durability and resiliency studies were completed for the adopted polydimethylsiloxane (PDMS) substrate in terms of bending, wet and temperature testing
ANTENNA DESIGN OVERVIEW AND MOTIVATION The proposed PDMS antenna in this paper exploits the TM010 and the TM001 modes of the folded-shorted patch (FSP) and these modes are achieved without the introduction of slots, as in [24] and [27], where the FSP antennas operated by the TM010 and TM030 modes

Summary

INTRODUCTION

W EARABLE antennas in recent years have advanced significantly and been researched for various applications. Preliminary results were reported by the authors in [25] for a simple and single-layer circularly polarized (CP) patch antenna where durability and resiliency studies were completed for the adopted polydimethylsiloxane (PDMS) substrate in terms of bending, wet and temperature testing Results suggest that such an antenna can withstand these operational conditions and without significant performance degradations in terms of variations in impedance matching and antenna gain. Following these developments some preliminary results for a three-layer FSP using PDMS were reported in [26] considering its potential for dual-band functionality.

ANTENNA DESIGN OVERVIEW AND MOTIVATION

ANTENNA SYNTHESIS AND ANALYSIS

TM010 AND TM001 MODE COMPARISON OF THE THREE-LAYER FSP ANTENNA AND THE

Findings

CONCLUSION