# Specific Resonant Properties of Non-Symmetrical Microwave Antennas
## 3 Results and Discussion
### Resonance Properties of Measured Flat Microwave Antennas
\begin{table}
\begin{tabular}{c c c c c c c} \hline
**20** & **30** & **40** & **50** & **55** & **60** & **70** & \(l\) [mm] \\ \hline
0.204 & 0.215 & 0.224 & 0.231 & 0.226 & 0.224 & 0.231 & \(l/\lambda\) (w = 5 mm) \\
0.171 & 0.190 & 0.203 & 0.222 & 0.226 & 0.229 & 0.240 & \(l/\lambda\) (w = 10 mm) \\
0.139 & 0.170 & 0.188 & 0.212 & 0.226 & 0.236 & 0.247 & \(l/\lambda\) (w = 30 mm) \\ \hline \end{tabular}
\end{table} 
Table 3: Resonance point values \(l/\lambda_{res}\) of flat microwave antennas. For the characteristic course of the change of the position of the resonant points of the whole set of flat microwave antennas, it is possible to assess the problem of frequency band coverage. Also, in this case, the whole set is represented by our 18 measured antennas, which are divided according to the width of the strip into three sets of six antennas. In terms of the frequency range, we also consider here only the values of the resonant points for the two \"edge\" (widest and narrowest) antennas from each set. 1. Set of antennas \(w=5\) mm Figure 12a 0.231-0.204 = 0.027
2. Set of antennas \(w=10\) mm Figure 12b 0.24-0.171 = 0.069
3. Set of antennas \(w=30\) mm Figure 12c 0.247-0.139 = 0.108  
The values of the difference of the resonant points \(\Delta\) (\(1/\lambda_{\text{res}}\)) of the flat microwave antennas are very different (0.027, 0.069, 0.108) and in this case, the differences according to the bandwidth are very significant. The difference in the values of the resonant points of the whole set of flat microwave antennas is determined by the antenna with the widest strip and it is relatively high at 0.108. Many of these results, with respect to the operating frequency and bandwidth of conventional cylindrical antennas and flat microwave antennas, are relatively well known. However, what was previously unknown is that the graphs of the dependence of the resonant frequencies of the flat microwave antennas on their length intersect each other, like the case shown in Figure 11. At the same thickness of the conductive strip from which the antennas are made and when displaying their frequency dependence on their length (where the width of the strip is the parameter), their characteristics intersect at one significant point \(S\). Conventional cylindrical antennas in the same conditions have no such point and display parallel characteristics like that in Figure 8. \begin{table}
\begin{tabular}{c c} \hline \hline
**Influence of the change \(\Omega\) of the flat antenna** & **Influence of the change \(\Omega\) of the flat antenna** \\
**on the change of the ratio \(l\lambda_{res}\)** & **on the change of the ratio \(l/\lambda_{res}\)** \\
**due to changing \(w\) at the same \(l\).** & **due to changing \(l\) at the same w.** \\ \hline \(\Omega_{w5}\,l_{20}>\Omega_{w10}\,l_{20}>\Omega_{w30}\,l_{20}\) & \(\Omega_{w5}\,l_{20}<\Omega_{w5}\,l_{25}<\Omega_{w5}\,l_{20}\) \\
0.204 0.171 0.139 & 0.204 0.226 0.231 \\ \(\Omega_{w5}\,l_{55}=\Omega_{w10}\,l_{55}=\Omega_{w30}\,l_{55}\) & \(\Omega_{w10}\,l_{20}<\Omega_{w10}\,l_{25}<\Omega_{w10}\,l_{20}\) \\
0.226 0.226 0.226 & 0.171 0.226 0.240 \\ \(\Omega_{w5}\,l_{70}<\Omega_{w10}\,l_{70}\,l_{70}\) & \(\Omega_{w30}\,l_{20}<\Omega_{w30}\,l_{55}<\Omega_{w30}\,l_{70}\) \\
0.231 0.240 0.247 & 0.139 0.226 0.247 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Values of resonance points \(l/\lambda_{res}\) of flat microwave antennas. Figure 12: Change of position of resonance points \(l/\lambda_{res}\) of flat microwave antennas when changing the slimmess coefficient \(\Omega\): (**a**) Resonance points of very narrow antennas w = 5 mm; (**b**) Resonance points of medium-wide antennas w = 10 mm; (**c**) Resonance points of very wide antennas w = 30 mm. Like in the previous case of the cylindrical antennas (Figure 10), in this case of displaying the results for flat microwave antennas (Figure 13) we also have chosen a non-traditional form of a graph for a large number of resonant points of our set of 18 flat microwave antennas.