EMC Testing for Electric Vehicle Chargers
The EMC standards electric vehicle chargers must meet, the challenges of high-power testing and the test chamber requirements.
3 min readNovember 4, 2026
A Pyramid-Shaped Test Environment
A GTEM cell is an enclosed, pyramid-shaped metal transmission line, narrow at one end and wide at the other. Inside is an asymmetrically placed conductive septum, and the wide end is closed with absorbers. This structure creates a uniform field inside that resembles a plane wave.
The product is placed in the test volume between the septum and the floor. Since the cell is shielded itself, it doesn't need a separate shielded room and can be installed in a corner of a lab.
What Is It Used For?
GTEM cells can be used for both emission and immunity testing. In immunity testing, high field strengths are reached with far less amplifier power than in an anechoic chamber, making economical pre-testing possible for small products.
For emission measurement, the product is measured in different orientations and the total emission is calculated. IEC 61000-4-20 defines testing in TEM waveguides.
Limits
The test volume is small; it isn't suitable for large products or systems with long cables. Cable layout inside the cell markedly affects the results, and replicating the certification lab's setup exactly is difficult.
As a result, GTEM results don't always match tests done in a semi-anechoic chamber. The cell is most useful for seeing trends and comparing design changes.
GTEM or a Pre-Test Chamber?
If your products are small and wireless or have short cables, a GTEM cell is a quick start. If your product range is growing or you test cabled systems, a compact SAC-3 chamber is a better investment.
We can work out together which suits you based on the size of the products you want to test and the standards. For the general benefits of pre-testing, see our pre-testing article for R&D teams.
Frequently Asked Questions
What frequencies does a GTEM cell cover?
Depending on size, typically from a few kHz to a few GHz. Larger cells offer a bigger test volume.
Are GTEM results accepted for certification?
Some product standards accept them under certain conditions, but most certification tests are done in a semi-anechoic chamber.
Does the cell need a separate room?
No, the cell is shielded itself. The area holding the measurement equipment should be tidy and grounded, however.
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