Electric field maps of an astable multivibrator in frequency range from 30 MHz to 3 GHz

The data presents a result of near field measurements of electromagnetic emissions radiated from the PCB of a small electronic device.  An efficient method of modelling the magnetic and electric field emissions is the measurements in the near field using electric and magnetic probes. The attached files contain electric field maps created on based measurements using E-Field Probe RF E 03 in the frequency range 30 MHz – 3 GHz.  The designated maps enable the location of the sources of high electric field radiated by the tested device. The device under test (DUT) was a typical astable multivibrator supplied from a battery of 9 V (Fig. 1).
Twenty-five measurement points are marked on the PCB, located exactly above the elements of the DUT (Fig. 2). The near fields were measured directly on the surface of PCB. The probe was placed at the same distance from the PCB surface, regardless of the height of the elements. The probe RF E 03 is a passive near-field probe. The electrode underneath the RF E 03 probe head is approx. 4 x 4 mm. With it, small E field sources can be localized, e.g. conducting paths, a single component of PCB. The probe head is positioned directly on the measured object (high electrical field strength). The average value of the voltage at the probe output was measured at all points with an oscilloscope. Each measurement was performed for the averaged instantaneous values (the number of averages above 300) for both the background, i.e. the device turned off and the device turned on. All results of measurements made with near field probes are presented in mV. This is due to the measurement of the voltage at the output of the probe for both electric and magnetic fields. In Figure 3, the near-field measurement system developed to measure the radiated emission is shown.
The attached files contain electric field maps and the table with the measurement results. Figure 1. The electronic diagram of the AVT 720 device Figure 2. Arrangement of measurement points on the DUT Figure 3. The near-field measurement system