Planar Textile Off-Body Communication Antennas: A Survey

Abstract

Fully textile smart wearables will be the result of the complete integration and miniaturization of electronics and textile materials. Off-body communications are key for connecting smart wearables with external devices, even for wireless power transfer or energy harvesting. They need to fulfill specific electromagnetic (EM) (impedance bandwidth (BW), gain, efficiency, and front to back radiation (FTBR)) and mechanical (bending, crumpling, compression, washing and ironing) requirements so that the smart wearable device provides the required performance. Therefore, textile and flexible antennas require a proper trade-off between materials, antenna topologies, construction techniques, and EM and mechanical performances. This review shows the latest research works for textile and flexible planar, fully grounded antennas for off-body communications, providing a novel design guide that relates key antenna performance parameters versus topologies, feeding techniques, conductive and dielectric textile materials, as well as the behavior under diverse measurement conditions.

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 ].…”

“…In the literature, a diverse range of techniques have been reported for reducing interaction between the antenna and human tissue. One popular technique to reduce electromagnetic coupling between the antenna and human body is to use metamaterials such as electromagnetic bandgap [ 10 , 11 , 12 , 13 , 14 ] and artificial magnetic conducting surfaces [ 16 , 17 ]. Another technique is to use a reflector [ 1 , 5 , 8 , 15 ] or a full ground plane [ 7 ].…”

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

“…Based on the far-field features, several performances were fulfilled satisfactorily, such as radiation pattern, gain value, and axial ratio. According to the review article presented in [51], Del-Rio-Ruiz et al stated that the textile and flexible antennas need careful trade-off between fabrics, topologies of antennas, design methods, and EM and mechanical capabilities. Besides, the analysis revealed the current research work for textile and flexible planar, totally grounded offbody communications antennas, including a novel design guide related to main parameters of antenna efficiency against topologies, feeding methods, conductive and dielectric textile materials, as well as an action under different measurement circumstances.…”

Synthesis, Characterization and Development of Energy Harvesting Techniques Incorporated with Antennas: A Review Study

“…Figure 9 indicates that the microstrip antenna consists of a radiation patch, a ground plane, a dielectric substrate, and a nourishing point that could be used in a variety of ways. The radiator patch dimensions thickness (h), width (W P ), and length (Lp) determine the bandwidth, resonant frequency, and efficiency of the microstrip antenna [ 71 ]. The polarization, frequency band number, antenna gain, and bandwidth are all determined by the shape of the radiator patch (rectangular [ 72 , 73 , 74 ], circular [ 75 , 76 ], square [ 77 , 78 ], and others [ 79 , 80 , 81 ]), as well as the feeding technique (position, type, and number of feeds).…”