Scanning of electromagnetic radiation for EMC and data security purposes

A semi-automatic measurement system and diagnostic tool for localization of radiating parts of electronic devices in near-field was developed. A near-field scanning of electromagnetic emission is performed by the system. Maximal spatial resolution of the scanning is 0.2 mm which is sufficient for exact localization of radiating parts in the most cases. Frequency range of the measurement is from 30 MHz to 3 GHz. The advantage of the system is simplicity of implementation, as it is based entirely on commercially produced devices. The test receiver Rohde & Schwarz ESPI7 was used for the measurement of radiation level. The advantageous functions of the receiver such as fast frequency scan and simultaneous measurement with three detectors was utilized. The scanning procedure is controlled by a program which leads a user throughout all measurement steps. The program was made in Agilent VEE Pro. Important part of the measurement is processing of the measured data. Therefore, software for effective data visualization and analysis was developed. The key functions of the program are projection of the measured data on a photograph of the tested device, peak search and highlighting of critical places. Results of the scanning of a main board of a personal computer are presented.