Characterization of electric fields in a GTEM cell [EMC measurement applications]

Two of the most important measurements related to electromagnetic compatibility (EMC) are radiated emission and radiated immunity. These measurements must be performed in a facility which provides reliability and reproducibility. The Gigahertz transverse electromagnetic mode (GTEM) cell is one of the facilities for EMC measurement due to its well defined electric and magnetic field distribution in addition to being cost effective. The research undertaken in this project is to determine the field distribution in the GTEM by using a finite difference time domain (FDTD) method. The electric field distribution for frequencies at 100 MHz, 200 MHz, and 400 MHz were calculated using the EZ-FDTD software. This was followed by making measurements of the field, based on the radiated immunity test setup. It is found that at a septum height of 63 cm for a frequency of 100 MHz, the measured and simulated results are very close. The difference varies from 0.01 dB to 4.91 dB.