Design and Evaluation of a Flexible Dual-Band Meander Line Monopole Antenna for On- and Off-Body Healthcare Applications  
[PERSON]  
1 Department of Electrical and Electronic Engineering, Universiti Teknologi, PETRONAS Bander Seri Iskandar, Tronoh 32610, Perak, Malaysia; [EMAIL_ADDRESS] (S.M.A. ); [EMAIL_ADDRESS] (T.S. ); [EMAIL_ADDRESS] (S.S.)  
[PERSON]  
1 Department of Electrical and Electronic Engineering, Universiti Teknologi, PETRONAS Bander Seri Iskandar, Tronoh 32610, Perak, Malaysia; [EMAIL_ADDRESS] (S.M.A. ); [EMAIL_ADDRESS] (T.S. ); [EMAIL_ADDRESS] (S.S.)  
[PERSON]  
2 Waert LLC  
be able to easily be integrated with electronic systems and maintain a reliable link while not causing any discomfort for the user. The human body is a hostile environment for an antenna due to the coupling and absorption of the EM waves [3]. Wearable antennas must be designed and characterized carefully in order to maintain a reliable communication link even under the detuning effects of lossy body tissues, because the human body can deteriorate the performance of the antenna [4]. To add to this complexity, it is worth noting that every individual has a composition of body tissue with different dielectric constants (\(\epsilon\)) and geometrical parameters [5]. However, the effect of coupling in the human body and wearable antennas can be mitigated by using de-coupling methods such as insolation and proper use of the ground layers. Small antennas with a truncated or no ground plane generally are omnidirectional, and therefore, are more affected by the body's coupling effect. This effect requires optimizing the antenna-body separation distance effectively [6]. The study and optimization of the antenna with small isolation from the body provide a simple and effective way of combating the detuning effect. Figure 1 shows the general architecture in WBAN systems. Numerous flexible textile antennas have been designed and evaluated in WBAN systems. For example, [PERSON] et al. integrated a planar monopole antenna with a layer of the artificial magnetic conductor (AMC) in [8]. The antenna was completely made of fabric using Pellon for the substrate, and pure copper taffeta for conducting parts. An impedance bandwidth of 4.30-5.90 GHz was observed. Effects of bending and crumpling were studied and the performance of the design on various body models was compared. [PERSON] et al. in [9] designed an inverted-F antenna on a felt substrate, and its performance was checked on various body locations. The impact of different materials, as well as bending, was studied. The bending effects significantly degraded the antenna's performance by changes in its distance from the body. [PERSON] et al. in [10] investigated a wideband antenna, working within the band of 0.9-6.0 GHz. The antenna performance was investigated under bending conditions, which showed a considerable change in the antenna's resonant frequency. In addition, the antenna's efficiency was improved by adding an electromagnetic bandgap (EBG) surface. In our work, a compact flexible dual-band meander line monopole antenna is proposed, and its performance was evaluated on different subjects with various bending and wet conditions, and at two operating bands with different body sizes, in which a wearable antenna is expected to operate for on-/off-body applications. Table 1 shows the comparison of this design with similar results from a few papers from the literature and improvements that were achieved. In particular, we have shown that the results are not sensitive to the presence of the human body, and insignificant detuning is observed at both bands when a  
Figure 1: A general healthcare architecture for integrated meander line antenna. WPPU: wireless patient portable unit; WAPU: wireless-access point unit; LAN: local area network; QoS: quality of service [7]. 10 mm distance was maintained. Moreover, these evaluations are influential in determining proper antenna operation on the human body, and also pave the way for unique designs as mentioned by [PERSON] et al.