Design and performance analysis of dual-band wearable compact low-profile antenna for body-centric wireless communications

Abstract

In this paper, we present a novel dual-band wearable compact flexible antenna for body-centric wireless communications (BCWCs). The design is based on a modified planar dipole with parasitic elements, meandered lines, and a rectangular reflector embedded into a hydrophobic rubber-textile multilayer substrate in order to get both good antenna performance and mechanical properties. The antenna's structure is analyzed and optimized in free space (FS), on a numerical and an experimental homogeneous flat phantom. The overall dimensions of the antenna are 50 mm × 40 mm × 4.6 mm and a prototype mass of 11 g, which makes it suitable for practical applications in BCWCs. The built prototype resonated at 2.47 GHz with a |S11|−26.90 dB and at 5.42 GHz with a |S11|−24.60 dB in the FS. The measured bandwidths are 500 MHz (2.2–2.7 GHz) and 1000 MHz (4.65–5.75 GHz) at lower and higher bands, respectively. The antenna exhibits a measured maximum gain of 1.17 dBi at 2.66 GHz and a radiation efficiency of 28.44% in FS. The 10 g average maximum specific absorption rate is 0.165 W/kg at 2.70 GHz and 0.520 W/kg at 5.24 GHz when the antenna is placed on the numerical phantom at net input power 0.1 W.

Wearable Textile Antennas with High Body-Antenna Isolation: Design, Fabrication, and Characterization Aspects

“…Hence, flexible, thinner, and low-cost materials should be chosen to make the antenna conformable to the person wearing the wearable device and to meet mechanical and manufacturing requirements. Materials like polymers [3,13], non-conductive fabrics [4], paper [14], and flex film [5,6] have been used as the substrates in the existing wearable antennas [3,15]. The choice of material for the antenna's substrate is a critical factor in the performance of the antenna and is examined in depth in Section 3.…”

“…Several antenna designs with a high degree of isolation between the antenna and human tissues have been reported. These designs use a full ground plane [15,18], an artificial magnetic conducting surface [19], a reflector [13], an electromagnetic bandgap structure [20], or substrate integrated waveguide techniques [2,21].…”

“…After that, a prototype of the optimized design of the wearable antenna can be fabricated using the methods for fabrication of flexible and wearable antennas presented in [5,8,13].…”

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

“…Wearable wireless sensor networks (W-WSNs) can be applied in diverse areas, including health care (clinical diagnostics, rehabilitation), sports (athlete activity profile, energy expenditure during training) and work safety (monitors for the temperature, humidity, CO 2 ) [ 1 , 2 ]. These networks are a particular case where sensors are deployed on the user clothing and/or directly on the body to measure physiological signals of a human and/or to monitor its environment [ 3 , 4 , 5 ]. Hence, each W-WSN consists of multiple wearable sensor nodes which are capable of communicating with each other (on-body communications) or with external devices (off-body communications) allowing a connection with a monitoring centre (smartphone, local or cloud webserver).…”

“…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 ].…”