Understanding Different EMI Shielding Effectiveness Tests

It is not simple to come up with the exact level of attenuation when using EMI shields, but there are several methods to help users retrieve the results they need. It is important to note that the result often do vary based on the shielding application. Knowing the four most common tests will allow you to calculate the effectiveness of your EMI shielding more accurately:

Shielded Room Test is best employed in situations where it is difficult or impossible to diminish the ambient noise in an area. The test works best for spaces using shielded room techniques. Proper testing equipment must be used to help make measurements. Ultimately, this process helps evaluate a device’s susceptibility

Shielded Box Test uses a sealed box with a portion cut-out. Conductively coated shields are then placed on the opening of the box. Then, all emissions (both transmitted and received) are measured.

Coaxial Transmission Line Test is best used for measuring plane-wave electromagnetic wave radiation. The test lets users know the effectiveness of the shielding. For this analysis, a reference testing device is needed. You will make a compassion between the reference and the load devices power ratios (without shielding).

Open Field Test simulates typical usage conditions. Antennas are used to help test equipment. This test is best for finished products.

If you have more questions about RFI and EMI shielding, let us be your first stop. We also work with EMI gaskets. Give us a call for more information.