GTEM cell

A GTEM cell
GTEM cell with side access door open showing RAM lining of end wall

A GTEM or Gigahertz Transverse Electromagnetic cell is a type of electromagnetic compatibility (EMC) test chamber used for radiated EMC testing.[1]

Description

A GTEM cell enclosure is made of conductive material such as metal, in the shape of a long, rectangular pyramid. The pyramid is normally laid flat on one side, although occasionally it may be stood on its base. The base is typically lined internally with radiation-absorbent material (RAM) but the side walls are left bare to act as a waveguide. An RF antenna is placed internally near the base, and a resistive RF absorber or load at the apex. In operation the equipment under test is placed in between the antenna and the load.

Principles of operation

The GTEM cell forms an enclosed TEM (transverse electromagnetic mode) stripline, which acts as receiving emissions or transmitting emissions antenna:

In operation, emitted radiation (whether from an antenna or from the EUT), travels along the length of the chamber and is absorbed by the absorbent load at the end.

For immunity tests, the field uniformity and the crosspolar coupling of the cell have to be within certain limits set by IEC 61000-4-20.[2]

References

Notes

  1. "GTEM". eevblog.com. Retrieved 2011-09-22.
  2. "York EMC, GTEM practice guide" (PDF). Retrieved 2013-01-18.

Bibliography

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