Compact and Low-Profile UWB Antenna Based on Graphene-Assembled Films for Wearable Applications

Abstract

In this article, a graphene-assembled film (GAF)-based compact and low-profile ultra-wide bandwidth (UWB) antenna is presented and tested for wearable applications. The highly conductive GAFs (~106 S/m) together with the flexible ceramic substrate ensure the flexibility and robustness of the antenna, which are two main challenges in designing wearable antennas. Two H-shaped slots are introduced on a coplanar-waveguide (CPW) feeding structure to adjust the current distribution and thus improve the antenna bandwidth. The compact GAF antenna with dimensions of 32 × 52 × 0.28 mm3 provides an impedance bandwidth of 60% (4.3–8.0 GHz) in simulation. The UWB characteristics are further confirmed by on-body measurements and show a bending insensitive bandwidth of ~67% (4.1–8.0 GHz), with the maximum gain at 7.45 GHz being 3.9 dBi and 4.1 dBi in its flat state and bent state, respectively. Our results suggest that the proposed antenna functions properly in close proximity to a human body and can sustain repetitive bending, which make it well suited for applications in wearable devices.

Small Antennas for Wearable Sensor Networks: Impact of the Electromagnetic Properties of the Textiles on Antenna Performance

“…Moreover, small, flexible, low-profile, and light-weight wearable antennas based on materials which are deformable, twistable and stretchable are needed because the sensor node needs to be seamlessly worn [ 7 ]. Most of the proposed flexible wearable antennas are based on polymers [ 5 , 8 , 9 ], textiles [ 1 , 7 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 ] or flexible ceramics [ 18 ].…”

Flexible Antennas: A Review

“…Many other polymer-based flexible UWB antennas were reported in the literature. These include liquid crystal polymer [ 158 , 159 , 160 , 161 ], polydimethylsiloxane (PDMS) [ 162 , 163 , 164 ], graphene-assembled film [ 165 ], artificial magnetic conductor (AMC) [ 166 , 167 , 168 , 169 , 170 ], PET [ 171 , 172 , 173 ], paper [ 174 ], and polyamide [ 175 , 176 , 177 ].…”

ON-OFF Body Ultra-Wideband (UWB) Antenna for Wireless Body Area Networks (WBAN): A Review

“…Wearable wireless devices have drawn growing focus to address the conformal question of portable antennas and fabrics. In [56], a versatile and compact portable CPW-fed antenna based on a highly conductive graphene-assembled film (GAF) and a super-flexible ceramic composite material have been presented by Fang et al (see figure 23). H-shaped slots significantly raise the performance bandwidth of the antenna such that the antenna realized impedance bandwidth of 67 % in the bending period and overall gain of 4 dBi.…”

“…Noteworthy, this paper is summarized as follows: a brief introduction to the wireless body area network-based UWB antenna design is given in section I. Then, detailed analysis is demonstrated in section II on (OFF-Body) communication by covering both monopole [33]- [56] and rear ground plane antenna types [57]- [69] alongside with their UWB applications. Section III concentrates on (ON-Body) communication antenna analysis and applications [70]- [86].…”