## 3 Design Procedure
#### (b2) Dielectric substrate material
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Antenna**} & \multirow{2}{*}{\begin{tabular}{c} **f\({}_{\text{c}}\)** \\ **(GHz)** \\ \end{tabular} } & \begin{tabular}{c} **S11** \\ **(dB)** \\ \end{tabular} & \begin{tabular}{c} **BW** \\ **(MHz)** \\ \end{tabular} & \begin{tabular}{c} **AR** \\ **(dB)** \\ \end{tabular} & \
\begin{tabular}{c} **e\({}_{\text{rad}}\)** \\ **(\%)** \\ \end{tabular} &
\begin{tabular}{c} **Gain** \\ **(dBi)** \\ \end{tabular} \\ \hline \multirow{2}{*}{REF1} & Simulations & 2.45 & \(-\)22 & 70 & 55 & 96 & 7.78 \\ \cline{2-8}  & Measurements & 2.47 & \(-\)35 & 79 & 18 & 94.7 & 6.90 \\ \hline \multirow{2}{*}{REF2} & Simulations & 2.33 & \(-\)9.1 & 120 & 1.9 & 94.7 & 8.20 \\ \cline{2-8}  & Measurements & 2.34 & \(-\)10 & 160 & 3.1 & 94.7 & 7.44 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Simulated and measured performance results for reference antenna frequency of operation (f\({}_{\text{c}}\)), reflection coefficient at f\({}_{\text{c}}\) (S11), 10-dB impedance bandwidth (BW), the axial ratio at f\({}_{\text{c}}\) (AR), radiation efficiency (e\({}_{\text{rad}}\)), and far-field gain (Gain). (e) Final CC antenna validation  
The final step in the design procedure is to fabricate and evaluate the CC textile antenna in terms of its expected/simulated performance. The challenging task is to diligently incorporate the selected clothing components into the antenna structure. For example, in [48], the Velcro hooks-part and the zip are sewn on the microstrip patch layer with a non-conductive yarn. This provides the necessary mechanical stability for the clothing components on the antenna. Attention needs to be given to avoid a major local compression of the textile substrate. After the CC antenna is fabricated, performance evaluation is conducted via measurements of the reflection frequency response (S11) and the far-field radiation properties (radiation pattern, gain, radiation efficiency, and axial ratio). The fabricated antenna's resonance response may differ from the simulated one. In this case, we should examine the prototype in terms of its geometrical characteristics that may be changed due to fabrication processes. For instance, the height of the textile substrate can be locally shrunk due to compression caused by the clothing components sewing. Furthermore, improper alignment of CC position into the antenna structure can impact the resonance response. Various research works present analytical comparison studies between simulation and measurements of CC textile antennas and factors of differences and improvements are described. In [44], the deviation in far-field gain is found to be 1 dB which is justified by imperfections in antenna \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Antenna**} & \(\mathbf{f_{c}}\) & **S11** & **BW** & \(\mathbf{e_{rad}}\) & **Gain** \\  & **(GHz)** & **(dB)** & **(MHz)** & **(\%)** & **(dBi)** \\ \hline REF & \multirow{2}{*}{2.45} & \multirow{2}{*}{\(-\)29.6} & \multirow{2}{*}{83.2} & \multirow{2}{*}{69.9} & \multirow{2}{*}{1.2} \\ (Pins) & & & & & \\ \hline CC & \multirow{2}{*}{2.446} & \multirow{2}{*}{\(-\)29.5} & \multirow{2}{*}{83.6} & \multirow{2}{*}{69.1} & \multirow{2}{*}{1.1} \\ (Snap-on buttons) & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Simulated performance results for reference antenna (Pins) and CC antenna (Snap-on buttons): frequency of operation (f\({}_{c}\)), reflection coefficient at f\({}_{c}\) (S11), 10-dB impedance bandwidth (BW), radiation efficiency (e\({}_{rad}\)), and far-field gain (Gain). Figure 11: Patch antenna modeled with shorting pins (**top**) and with snap-on buttons (**bottom**): (**a**) Side views; (**b**) Top views (not on the same scale). fabrication and inaccuracies in measurements. Furthermore, this work proves that since the CC is modeled in detail and as accurately as possible, then, the measurements will approach the numerical results.