On the Design and Performance Analysis of Flexible Planar Monopole Ultra-Wideband Antennas for Wearable Wireless Applications

Abstract

With the promising developments in wearable communication technology, attention towards flexible electronics is increasing day-by-day. This study presents flexible low-profile ultra-wideband (UWB) antennas for wearable applications. The antenna comprised of a modified dewdrop-inspired radiator and a defected ground plane and has an impedance bandwidth of 3.1–10.6 GHz. The antenna flexibility is investigated using four different substrates (polyester, polyamide, denim, and Teslin) and tested on a cotton shirt and a high-end Res-Q jacket to evaluate their performance stability for body-worn applications. The fabricated planar dewdrop-shaped radiator (PDSR) antennas have a radiation efficiency of >90%, a gain of >4 dBi, and a group delay variation of fewer than 0.5 ns. The antenna conformability is measured by placing the fabricated antennas on various curved and nonplanar parts of the human body. The aforementioned antennas offer better flexibility for different bent conditions. The specific absorption rate (SAR) of the designed antennas is investigated to determine their wearability, and values are found to be less than 0.2 W/Kg. Also, the received signal strength (RSS) is discussed in order to analyze signal attenuation, and the performance analysis of the antennas is compared.

On the design and analysis of a miniaturized ultra‐wideband (UWB) antenna using quatrefoil‐shaped nonuniform meta‐surfaces for body‐centric communications

“…Also, except De et al, 7 the proposed antenna offers higher bandwidth than all the antennas given in the table and higher bandwidth with dual mode operation than the previous studies 5,29,40,50 . The proposed antenna also provides better gain than previous literature 5,7–9,11–13,17,18,34,38,46,50 . Better efficiency is also achieved when compared to other studies 5,7,12,18,38,40,46 .…”

“…5,29,40,50 The proposed antenna also provides better gain than previous literature. 5,[7][8][9][11][12][13]17,18,34,38,46,50 Better efficiency is also achieved when compared to other studies. 5,7,12,18,38,40,46 This proves that the antenna proposed is a better candidate for body-centric communications.…”

“…It is understood from Table 5 that the proposed antenna is smaller in size (length × width) than the antennas in literature 7,8,12,13,18,29,40,50 and lesser in thickness than 5,7,9,11,13,17,18,29,34,38,40 . This lesser thickness of the antenna results in reduced overall volume.…”

“…A CPW‐fed monopole antenna with denim substrate is presented in De et al 7 The antenna provides good bandwidth and gain using defected ground structures with omnidirectional radiation for on body applications only. A dewdrop‐shaped UWB antenna in Thangarasu et al 8 is made of four different substrates. The ultra‐wide bandwidth was achieved using defected ground plane with the overall dimension being a bit more.…”

A dual band CPW-fed MIMO antenna for fifth generation application

“…The antenna design results in resonance at 3.5 GHz and 5.9 GHz. The MIMO antenna [19][20][21][22] is tested where good agreement is achieved between overall results. The MIMO antenna design suggested in [23] comprises four identical radiating elements in an octagonal shape.…”