## 3 Results and Discussion
tolerances of 25 microns, 100% of the devices would be acceptable. If the tolerance were extremely high, for instance, 50 microns, 99% of the prototypes would be acceptable; even for the unlikely case of an excessively high tolerance of 100 microns, 96% of the prototypes could be still acceptable. This reveals the accuracy of the design and the high tolerance for manufacturing errors of this prototype. The results above prove the feasibility of this prototype and validate the simplicity and endurance of its fabrication procedure. To contextualize this new patch antenna device, the performance indexes of different air substrate microstrip patch antennas with just one radiating element are compared in Table 2 regarding the resonance frequency, the return loss, the fractional bandwidth, the gain, the efficiency, and the feeding technique; qualitative aspects about the manufacturing complexity and other details of the prototypes are also included. The data in the table show that every published antenna can stand out in one or two performance indexes, and it also clearly reveals that this new antenna is the only one that is simultaneously completely dielectricless, able to achieve good values at the same time in all of the performance indexes, very easy to manufacture, and uses just one holder for both feeding the patch and fixing its position. The same happens if this antenna is compared with other patch antennas using different substrates, such as those in the compilation included in [27]. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Ref.** & \(f_{r}\) **(GHz)** & \(R_{L}\) **(dB)** & \(BW\) **(\%)** & \(G\) **(dBi)** & \(\eta\) **(\%)** & **Feeding** &
\begin{tabular}{c} **Manufacturing** \\ **Complexity** \\ \end{tabular} & **Comments** \\ \hline
[16] & 0.445 & 32.00 & 4.50 & 8.55 & 95.00 & mstrip-coax & easy &
\begin{tabular}{c} only simulation, aluminium \\ patch, eight holders \\ \end{tabular} \\ \hline
[17] & 1.9 & — & 34.90 & 6.60 & 75.00 & coax-L\_probe & very difficult &
\begin{tabular}{c} water-based, \\ transparent patch \\ \end{tabular} \\ \hline
[21] & 2 & 24.00 & 7.00 & 6.60 & — & coax-mstrip & very difficult &
\begin{tabular}{c} complex structure, \\ dual polarization \\ \end{tabular} \\ \hline
[11] & 2.44 & 30.00 & 4.94 & 9.78 & 99.00 & coax & easy &
\begin{tabular}{c} additional metallic \\ holding post, \(\eta\) simulated \\ \end{tabular} \\ \hline
[14] & 2.45 & 23.00 & 5.00 & 7.91 & — & mstrip & easy &
\begin{tabular}{c} air-gap, \\ non-dielectricless \\ \end{tabular} \\ \hline
[15] & 2.45 & 26.50 & 5.00 & 3.90 & 89.00 & coax & medium &
\begin{tabular}{c} shorting posts, slots \\ \end{tabular} \\ \hline
[18] & 2.45 & 20.00 & 3.00 & 8.51 & — & mstrip-insets & medium & air cavity backed \\ \hline
[28] & 2.44 & 21.00 & — & 8.40 & 88.00 & mstrip-coax & difficult &
\begin{tabular}{c} dual band, semi-circular \\ slot, four holders \\ \end{tabular} \\ \hline
**This** & **2.4** & **30.00** & **10.41** & **9.63** & **96.41** & **mstrip-through\_wire** & **very easy** &
\begin{tabular}{c} **single holder**, \\ **completely dielectricless** \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Comparison of measured performance parameters of air substrate patch antennas. Figure 6: Polar plot cuts of measured electric field radiation. From left to right: plane XZ, plane YZ, and plane XY.