Design and Evaluation of a Flexible Dual-Band Meander Line Monopole Antenna for On- and Off-Body Healthcare Applications

Abstract

The human body is an extremely challenging environment for wearable antennas due to the complex antenna-body coupling effects. In this article, a compact flexible dual-band planar meander line monopole antenna (MMA) with a truncated ground plane made of multiple layers of standard off-the-shelf materials is evaluated to validate its performance when worn by different subjects to help the designers who are shaping future complex on-/off-body wireless devices. The antenna was fabricated, and the measured results agreed well with those from the simulations. As a reference, in free-space, the antenna provided omnidirectional radiation patterns (ORP), with a wide impedance bandwidth of 1282.4 (450.5) MHz with a maximum gain of 3.03 dBi (4.85 dBi) in the lower (upper) bands. The impedance bandwidth could reach up to 688.9 MHz (500.9 MHz) and 1261.7 MHz (524.2 MHz) with the gain of 3.80 dBi (4.67 dBi) and 3.00 dBi (4.55 dBi), respectively, on the human chest and arm. The stability in results shows that this flexible antenna is sufficiently robust against the variations introduced by the human body. A maximum measured shift of 0.5 and 100 MHz in the wide impedance matching and resonance frequency was observed in both bands, respectively, while an optimal gap between the antenna and human body was maintained. This stability of the working frequency provides robustness against various conditions including bending, movement, and relatively large fabrication tolerances.

Design and Evaluation of a Button Sensor Antenna for On-Body Monitoring Activity in Healthcare Applications

“…As a result, the SAR levels are limited to protect safety the human body from thermal radiation. Therefore, SAR is linked to E-fields and tissue conductivity [ 43 ]: where shows the tissue conductivity and is its density. Alternatively, SAR shows the time derivative of the dissipated absorbed energy ( ) in mass ( ) in a volume ( ) of a provided density ( ).…”

Impact of Various Wearability Conditions on the Performances of Meander-Line Z-Shaped Embroidered Antenna

“…Due to the ease of integration into clothing and the conformal nature of fabrics, studies of flexible and wearable antennas using textile dielectric materials are becoming more popular compared to conventional rigid substrates [13]. However, in many of these structures, a number of additional layers were stacked between the radiating patch and the ground plane to get the required substrate thickness.…”

“…e research activities in the area of antennas for bodycentric and other various wearable applications are focused on the design of flexible and conformable antennas that are technically suitable and aesthetically acceptable to be worn on the human body [9][10][11][12]. Various effective and interesting techniques, such as planar inverted antennas, the use of high relative permittivity materials, and meander-line designs, were proposed [13][14][15] for the miniaturization of antennas and enhancement of bandwidth. Meander-line technology allows us to achieve a reduction in the size of antennas by combining a set of horizontal and vertical lines and folding them back and forth at right angles to maintain a reduction in the overall antenna length [16,17].…”

“…Compared to other manufacturing methods, embroidery is the most preferable and cost-effective technique for textile antennas. An integrated planar monopole antenna was designed and fabricated in [13,30], using Pellon fabric as a substrate and pure copper taffeta for the conducting parts. Different textile-based antennas were also studied in [30][31][32], where the ground plane and the patch were designed on different planes and a number of additional layers were sandwiched in between them to get the required substrate thickness.…”

Editorial for the Special Issue on Security and Sensing Devices for Healthcare Technologies

“…In the paper [ 2 ], Design and Evaluation of a Flexible Dual-Band Meander Line Monopole Antenna for On- and Off-Body Healthcare Applications, a flexible dual-bank meander lien monopole antenna used for on- and off-body person monitoring is introduced. It is another application, specifically for the healthcare sector, using micro-/nano-scaled structures.…”