Flexible circularly polarized antenna with axial ratio bandwidth enhancement for off‐body communications

Abstract

A flexible circularly polarized (CP) wearable antenna is proposed for a wireless body area network at the 5.8-GHz industrial, scientific, and medical band. The proposed antenna is made of flexible polyimide and foam material. The CP radiation is enabled by loading two pairs of shorting pins on a rectangular patch antenna. The 3-dB axial ratio (AR) bandwidth is doubled by adding two inverted L-shaped parasitic stubs on both sides of the antenna. For validation, the antenna with the dimensions of 0.68λ 0 � 0.68λ 0 � 0.044λ 0 was fabricated and measured invariousscenarios with an impedancebandwidth of 6.6% (5.67-6.05GHz), an AR bandwidth of 3.85% (5.730-5.955GHz),and a peak gain of 7.2 dBi.The measured radiation in the off-body direction is achieved with a half-power beamwidth of 65°and a 3-dB AR beamwidth of 84°. With the specified input power of 100 mW, the specific absorption rates are 0.613 and 0.294 W/kg in 1-g and 10-g average tissues. Moreover, through analysing the link budget a reliable communication can be guaranteed within 20 m in indoor line-of-sight environments.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Circularly Polarized Textile Sensors for Microwave-Based Smart Bra Monitoring System

“…In this paper, a wearable bra is proposed to monitor and scan for breast cancer. This Smart Bra is presented as a component of a WBAN system such that women will not need to regularly visit a hospital [ 7 ].…”

“…Moreover, it is a good choice for encountering multipath fading and establishing reliable channels when compared with linearly polarized (LP) antennas, especially in crowded interior environments [ 1 , 2 , 3 , 4 , 5 ]. However, only a few works focus on the CP MS wearable antennas [ 1 , 2 , 3 , 5 , 6 , 7 ].…”

A Wearable Circularly Polarized Antenna Backed by AMC Reflector for WBAN Communications

“…However, the most reported CP antennas applied for WBAN applications are based on rigid substrates, which cannot exhibit conformal characteristics. In this area, few research works on CP wearable antennas have been reported [29]- [32]. The multilayer flexible CP antenna is introduced in [29].…”

“…In this area, few research works on CP wearable antennas have been reported [29]- [32]. The multilayer flexible CP antenna is introduced in [29]. In [30], a costly CP antenna has been suggested by using flexible polydimethylsiloxane (PDMS) as a substrate.…”

High gain couple feed multiband wearable antenna for 5G and sub‐6 GHz communications

“…21 However, non-flexible substrates could not comfort in the proximity of the body. Therefore, flexible substrates, such as textile, 22 were utilized to design wearable CP antennas. Besides, some other CP wearable antennas with narrow axial ratio (AR) bandwidth are reported in Reference 23.…”