# Characterization of a Mechanical Antenna Based on Rotating Permanent Magnets
## 4 Results  
### Numerical Results  
For the CRRM studied in steady state (static regime), several values of the remanent magnetization were considered: \(B_{\mathrm{r}}\) = {1; 1.05; 1.1; 1.17; 1.21} T and a relative permeability \(\mu_{\mathrm{r}}\) = 1.0446. The dependence of the magnetic field induction with the distance is presented in Figure 9 for the values obtained from the numerical models (the dashed lines) as well as for the values (red line) measured by using the experimental setup in Figure 7. The variation of the magnetic field induction over the range 0-100 mm is shown in the top graph and that over the range 50-100 mm is shown in the bottom graph.  
The values obtained with the help of the numerical models were selected and compared with those obtained experimentally; thus, the relative errors and the root mean square deviation were determined (Figure 10).  
\begin{table}
\begin{tabular}{c c} \hline \hline
**Narda EHP-50F** & **Magnetic Sensor Coil** \\ \hline Frequency range: 1 Hz–400 kHz & 38,000 turns; \\ Measurement domain (B): 0.3 nT–10 mT & Resistance (R): 7.2 k\(\Omega\) \\ Dynamic range: \(\gtrsim\)105 dB & Inductance (L) = 236.8 H @ 1.6 Hz \\ Dimensions: 92 mm \(\times\) 92 mm \(\times\) 109 mm & Medium diameter: 160 mm \\ Software: EHP50-TS & Made in house \\ \hline \hline \end{tabular}
\end{table}
Table 3: The field sensors used for measuring the magnetic field generated by the rotating magnets.  
Figure 9: The dependence of the magnetic field induction with the distance, obtained in steady state for the CRRM, (**a**) over the range 0–100 mm and (**b**) over the range 50–100 mm.  
As can be seen, the smallest differences are obtained in the case of the remanent magnetization value of \(B_{\rm r}\) = 1.17 T. For the interval 0-80 mm, the relative errors have values below 5%, after this interval, they reach values of 6.98% and 8.45%.  
The numerical model for the CABM is similar to the one presented above; only the geometry of the permanent magnet has been modified. After applying the 2 nd order mesh distribution, a total number of nodes of over 4.4 \(\times\) 10\({}^{6}\) was obtained.  
For the CABM studied in steady state (static regime), several values of the remanent magnetization were considered: \(B_{\rm r}\) = [1; 1.05; 1.1; 1.17; 1.21] T and a relative permeability \(\mu_{\rm r}\) = 1.0446. The dependence of the magnetic field induction with the distance is presented in Figure 11 for the values obtained from the numerical models (the dashed lines) as well as for the values (red line) measured by using the experimental setup in Figure 7. The variation of the magnetic field induction over the range 0-100 mm is shown in the top graph and that over the range 50-100 mm is shown in the bottom graph.  
Figure 11: The dependence of the magnetic field induction with the distance, obtained in steady state for the CABM, (**a**) over the range 0-100 mm and (**b**) over the range 50-100 mm.  
Figure 10: (**a**) The relative errors obtained after comparing the values obtained numerically and those obtained experimentally; (**b**) the root mean square deviation.  
The values obtained with the help of the numerical models were selected and compared with those obtained experimentally; thus, the relative errors and the root mean square deviation were determined (Figure 12).  
As can be seen in Figure 12, the smallest differences are obtained in the case of the remanent magnetization value of \(B_{\mathrm{r}}=1.21\) T. For the interval 5-60 mm, the relative errors have values below 5%.