## 4 Experimental Evaluation
### Clothing Component Experimental Evaluation  
Dedicated evaluation scenarios and measurement methodologies can be used for the experimental evaluation of WTA which applies to clothing components. In addition to the described scenarios, in the CC performance evaluation, further scenarios should be examined including the nature and use of the CC. In [48], the use of a conductive Velcro and a zip fastener in reconfiguring the polarization properties of a textile patch antenna was presented and examined in terms of repeatability. Specifically, the consistency of antenna performance after 10 cycles of using the CCs was examined. These 10 cycles can represent different users' manipulation of the clothing components (Figure 13). These repeatability measurement scenarios take into account the mechanical nature and reconfigurable use of these CCs. A statistical analysis was then presented to prove an acceptable performance of these components. The Velcro tapes yielded a more stable and repeatable antenna performance than the zip. Still, the zip enabled an adequate antenna performance. Furthermore, in [40] the use of conductive snap-on buttons proved to present excellent repeatability characteristics based on measurements of the reflection S11 and transmission S21 parameters. There are cases that the clothing components can be used as a means of antenna feed attachment and interconnection as in [47]. In that specific application of a CC, it is useful and critical to experimentally examine the most effective way of using a non-conductive component in terms of performance. A non-conductive Velcro, as presented in [47], has been examined in terms of practical use and interconnection between textile transmission lines in [127]. Some concepts that were examined are shown in Figure 14. The results of transmission losses indicated that this textile fastener can be a proper candidate for the development of a practical \"user-friendly\" wearable system. Furthermore, the effective use of the non-conductive Velcro for attaching the feed transmission line of a textile patch antenna is shown in Figure 15. Measurements of the performance of the interconnection of the transmission line with the textile patch antenna have been carried out and validated the concept. Therefore, an all-textile antenna structure has been developed to enhance wearability by avoiding the use of rigid connectors. As previously described, the zip has been used not only as a part, or a means of specific antenna geometry configuration but as an antenna itself. In the case of the zip monopole antenna [49; 50], various lengths of the open zip state have been investigated. This analysis revealed the tunable property of a zip. Still, measurements should be carried out to assess the repeatability of the various tuning positions of the opened zip length. Furthermore, in the case of the handbag zipper antenna [51], various locations for positioning the feed probe of the SMA connector were examined to improve the antenna performance. It seems that the nature of the zip can offer the ability of different feed locations compared with a conventional textile antenna, e.g., monopole antenna. Therefore, testing different feed locations on a zipper antenna structure belongs to this specific category of CC experimental evaluation. Figure 13: _Cont._  
In [44], a modified snap-on button which includes a DC voltage PCB control circuit with a diode has been designed and examined, firstly, as a PCB in terms of circuit analysis  
Figure 14: Non-conductive use of Velcro for interconnection of textile striplines in various ways of usage. Figure 13: Repeatability measurements (4 of 10 use cases) of Velcro (**left**) and zip (**right**) clothing components. Figure 15: Non-conductive use of Velcro for interconnection of textile stripline with textile patch antenna. and, then, embedded into the antenna structure for evaluating the whole system. It can be seen that the clothing components can be modified to include a PCB circuit.