Abstract
In this paper, impedance matching enhancement of a grounded wearable low-profile loop antenna is investigated using a high-impedance surface (HIS) structure. The wearable loop antenna along with the HIS structure is maintained low-profile, making it a suitable candidate for healthcare applications. The paper starts with investigating, both numerically and experimentally, the effects of several textile parameters on the performance of the wearable loop antenna. The application of impedance enhancement of wearable grounded loop antenna with HIS structure is then demonstrated. Numerical full-wave simulations are presented and validated with measured results. Unlike the grounded wearable loop antenna alone with its degraded performance, the wearable loop antenna with HIS structure showed better matching performance improvement at the 2.45 GHz-band. The computed overall far-field properties of the wearable loop antenna with HIS structure shows good performance, with a maximum gain of 6.19 dBi. The effects of bending the wearable loop antenna structure with and without HIS structure as well as when in close proximity to a modeled human arm are also investigated, where good performance was achieved for the case of the wearable antenna with the HIS structure.
Highlights
Wearable sensors have received much attention in recent years and are becoming common and most desirable in lots of consumer-related electronics, due to their ease of integration with fabrics and electronic components and circuits, flexibility and conformability [1,2,3]
One more aspect that this paper aims to explore is the development of low-cost conductive tape based-textile sensor as an effective manufacturing technique for metallic layers of a multi-layer based textile antenna instead of the use of conductive textile yarns in computer-aided embroidery [1,19]
Based on the numerical full-wave simulations, it can be observed from Figure 26 that the high-impedance surface (HIS) structure had maintained good performance of the wearable loop antenna, while the wearable loop antenna without the HIS structure had resulted in major shift to its resonance frequency due to the close proximity to the highly lossy human arm tissues
Summary
Wearable sensors have received much attention in recent years and are becoming common and most desirable in lots of consumer-related electronics, due to their ease of integration with fabrics and electronic components and circuits, flexibility and conformability [1,2,3]. With particular emphasis on biological related applications, such devices, including wearable sensors (antennas), are capable of sensing, monitoring and wirelessly interconnecting with other nearby wearables in what is known as body-centric networks [4,5,6] Performance of such wearable radiators in terms of impedance matching, gain, efficiency, and roboustness may severely degrade when in close proximity to human body or tissues depending on number of factors including, but not limited to, deployed antenna and design complexity, nature of textile-based materials, channel losses within human body tissues. Sensors 2020, 20, 3809 reducing impedance mismatch of wearable antennas with ground plane when placed in close proximity to human body [9] Such metallic reflectors result in performance degradation of wearable low-profile antennas, depending on the deployed antenna design, textile fabric and how far the wearable radiator is from the metallic reflector.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
