In a GTEM cell small and medium size devices can be tested for electromagnetic immunity and emitted interference. The cell provides a well defined operating environment for testing the electromagnetic compatibility (EMC). The GTEM cell makes it possible to check the functionality of a device in a defined transverse electromagnetic field. In addition the emission of the device under test (DUT) can be measured. The DUT has to be complied with the industry valid standard norm EN- 61000-4-20. The measurement and calibration can be carried out in relatively short time. For example the emission of mobile devices, the sensitivity of receivers and the shielding efficiency of housings can be evaluated in a broad frequency range.
The shielded cell avoids the emission of electromagnetic interference to the environment and, the other way around, no external influence can disturb the measurement.
An electromagnetic field with different wavelengths is used, to check the interference resistance of electrical devices. The DUT is placed at a defined position within the GTEM cell and a signal generator for transient or periodic signals is connected at the socket connector of the cell. Between the septum waveguide and the outer conductor an electromagnetic field in the frequency range from dc up to 18 GHz is generated. A DUT is immune to interference if the DUT operates without errors during the test.
Additionally the emissions of the DUT can be measured at least up to 1 GHz. Therefore a spectrum analyser or a measurement receiver must be connected. The DUT emits an electric and a magnetic field during its operation. A voltage measurement with respect to every spatial axis is performed at the socket connector of the GTEM cell. These measured voltage values can be converted to field strength values by a PC in order to compare them to standard limits of radio interference.