GTEM Cell: what it is
A GTEM cell (Gigahertz Transverse Electromagnetic) is a type of electromagnetic test chamber that is used for testing the electromagnetic compatibility (EMC) and electromagnetic interference (EMI) of electronic devices, antennas, and other wireless communication systems. GTEM cells generate a transverse electromagnetic field, which is characterized by a uniform field strength across the cross-sectional area of the chamber. This allows for efficient and accurate testing of devices across a wide frequency range, from a few MHz to several GHz. It has a unique design that allows it to be used for both emission and immunity testing. Emission testing involves measuring the amount of electromagnetic energy that is emitted by a device, while immunity testing involves subjecting a device to a known electromagnetic field to determine its susceptibility to interference. These are widely used in industries such as telecommunications, aerospace, and defense, where the electromagnetic compatibility of electronic devices is critical to their performance and safety. They are also used in research and development to study the electromagnetic properties of materials and devices. Overall, these are valuable tools for testing and ensuring the electromagnetic compatibility of electronic devices, and they continue to play an important role in the development and deployment of new wireless communication technologies.
What it is for
The GTEM cell forms a closed TEM (transverse electromagnetic mode) stripline, which is used as an emission receiving or transmitting antenna. In particular, it is used:
- when measuring radiated emissions, one end of the stripline is connected to a spectrum analyser
- when performing radiated immunity, one end of the stripline is connected to a radiation source
- in operation, radiation emitted by an antenna or the equipment under test travels the length of the chamber and is absorbed by the absorbing load at the end
- for immunity tests, the field uniformity and the cross-polar coupling of the cell have to be within certain limits set by IEC 61000-4-20.