Compact EMC Test cells – Affordable RF radiated emission and immunity test environments
The advantages of performing radiated emission and immunity test early in the design of new products are significant in optimizing development and production cost and to assure no delays in the time to market.
However deploying these radiated tests bring several challenges:
- Emission measurements in open air are compromised by the ambient noise and nearby emitters such as radio stations, wireless communication, etc.
- Immunity test must be done in a screened room or cell in order not to contaminate the surrounding area and require significant amplifier power to achieve the required testlevels.
GTEM cells have been around for many years as a low-cost solution and alternative to performing EMC tests in a semi-anechoic chamber.
The uniform field area between the signal-carrying septum and body in the GTEM cell allows for simplified emissions test with results correlated to an OATS field strength (combining the measurements in X, Y and Z-directions).
While the field strength for radiated immunity testing in a GTEM cell is directly related to the distance between the septum and the body, the required input power to achieve the same level is much lower than in a FAR.
The advantages of using GTEM cells for economical EMC testing and faster time to market are clear.
Accelonix provides a full range of GTEM testcells.
But in some case the size of a GTEM cell is too big!
Due to the tapered design, a cell to test a 300mm high EUT must be more than 4 meters long.
Not all in-house or pre-compliance testlabs can accommodate such volume.
This calls for a test cell that is more compact and economical.
The LaplaCell is a modified form of GTEM cell, using a balanced dual septum design which maximizes EUT volume for a given external size of cell, and dramatically improves field linearity. The result combines the benefits of the linear wave through the EUT volume with the advantages of a much more compact, lower cost design.
Like GTEM cells, the Laplacecells are calibrated in accordance with IEC61000-4-20. Both for radiated emissions and immunity testing. Two types are available:
- Lc300: for EUT up to 30cm cube
- Lc600: for EUT up to 60cm cube (incl. 19″ racks up to 13HU)
An additional advantage of the LaplaCell is the integrated field sensor. There is no need for an extra field probe, thus minimizing further the investment for a IEC61000-4-3 testsetup.
LaplaCells are specifically intended for use by manufacturers so that they can test their own products more efficiently with minimizing the cost for external EMC testing.