EMI Shielding Products
- Custom Gasket Fabrication
- Connector Gaskets
- Bonded O Ring
- Custom Gaskets
- Conduct-O-Knit Knitted Wire Mesh
- Conduct-O-Seal Combo Gasket
- Conduct-O-Elastomer
- Conduct-O-Seal Oriented Wire in Silicone Gasket Material
- Conduct-O-Mesh Tape
- Conduct-O-Foam
- Conduct-O-Bond
- Optical Filters For Electronic Displays
- Shielded Vent Panels
- ESC Board Level Shielding
- 300 Series
EMI Shielding Measurements and Testing
One of the principal indicators used for measuring the effectiveness of EMI Shielding is call attenuation. 
This principle refers to differences between the intensity of electromagnetic signals prior shield and its intensity after having a shield installed. Attenuation uses decibels (dB) as a reference point that corresponds to ratios between field strength—without and with the presence of a protective medium. If there is a decrease in a signal’s intensity or amplitude is exponential with distance, the decibel range falls on a logarithmic scale. Under this circumstance, attenuation rating 50 dB refers to shield strengths of ten times that of 40 dB. Anything that is below 30 dB is considered the lowest effective rating for EMI or RFI shielding. Sixty to ninety dB is high protection, whereas up to 120 dB is deemed to be exceptional.
It is possible to determine attenuation levels for the EMI shield, although the testing can be a bit complex. Testing methods vary depending on the particular shielding application. The four most common tests include:
- Open Field Test: this specific test was designed to simulate normal usage conditions for electronics. Antennae are placed in areas devoid of metallic materials (outside of testing equipment). The results are logged by a noise level meter, which detects levels of EMI.
- Coaxial Transmission Line Test: this variant will measure plane-wave field electromagnetic wave radiation that can accurately determine shield effectiveness of a planar material.
- Shielded Box Test: the box technique uses a sealed box that has a cut-out section. Conductively coated shield is placed over the box's opening. After, all transmitted and received emission are carefully measured. Do not use this test when exceeding frequencies of 500 Megahertz.
- Shielded Room Test: when other testing methods fail, individuals, begin to rely on the room technique. The test requires two shielded rooms that have a wall between them. This test is excellent for understanding a devices susceptibility.
Shielding EMI
Call our team for more information on RFI shields and EMI shields.
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