**6.1 Measurement of magnetic near-field radiated by polyester capacitors**

Based on the frequency measurement method, we measured the vertical component Hz of the magnetic field radiated above a metalized polyester capacitor of a 1 μF capacitance and having a maximum voltage of 100 V (the capacitor size 14 mm x 7 mm x 18 mm). In order to have only the magnetic field radiated by the capacitor, the capacitor legs are bent. The probe was located at a 3 mm distance from the capacitor. The magnetic field measurements were performed in a plane whose dimensions were 30 mm x 20 mm with a measuring step of 1.5 mm on the X-axis and 1 mm on the Y-axis. **Figure 20** shows the measurement plane and the component under test.

**Figure 20.** *(a) Measurement plan; (b) device under test.*

*Development of Generic Radiating Model for Rectangular Capacitors: Magnetic Near Fields… DOI: http://dx.doi.org/10.5772/intechopen.98894*

After making Fast Fourier transformation (FFT) of the measured signals above the capacitor, we notice that the frequency of 26 MHz has maximum amplitude. We present in the following **Figure 21** the cartographies of the Hz and Hy components measured at the frequency of 26 MHz.

#### **6.2 Radiated-field modeling**

As for the polypropylene capacitor, the radiation of the polyester capacitor looks like that of a rectangular loop. The same method exposed previously is used to the cartography of the measured magnetic field Hz at the frequency of 26 MHz. The modeling result is a rectangular current loop whose parameters are given in **Table 2**. **Figure 22** exposes the cartographies of the magnetic field Hz measured and estimated by the obtained model above the capacitor. A good agreement between the two cartographies is observed.

#### **6.3 Model validation**

To validate the obtained model better, we examined the cartographies of the other components of the magnetic field above the capacitor. We specifically compared the measured component, Hy of the magnetic field, calculated using the obtained model (**Figure 23**).

The previous results show that the magnetic field reconstructed by the model resembles, to a great extent, the measured magnetic field.

**Figure 21.** *Cartographies of the field above the capacitor: (a) Hz and (b) Hy.*


#### **Table 2.**

*Parameters of the equivalent model of the metallized polyester capacitor.*

**Figure 22.** *Measured and estimated cartographies of polyester capacitor.*

**Figure 23.** *Cartographies of measured and estimated Hy component of the magnetic field above the capacitor.*
