York EMC Services Ltd provides a range of testing services to determine the EMI shielding effectiveness of both materials and enclosures.
It is desirable to demonstrate that EM shielding meets the requirements of current standards.
York EMC Services Ltd has the expertise and capacity to undertake such tests.
Being the UK’s leading experts in EMC research, we are also best placed to understand your requirements and explain the testing process to you. Our expertise is demonstrated by our EMC training courses which include modules on shielding effectiveness.
Our services in shielding effectiveness comprise testing, training and instrumentation.
Test method consistent with the American Society for Testing and Materials (ASTM) standard, Designation D 4935.
Measurement method valid over a frequency range of 30MHz to 1.5GHz.
Test method provides a procedure for measuring the EM shielding effectiveness of planar material due to a plane-wave, far-field EM wave.
Testing carried out at the University of York.
An alternative Magnetic Loop Test can also be performed for the lower frequency range up to 30MHz.
This kind of testing is aimed at EMI shielding technology companies who manufacture shielding materials e.g. metals, plastics, cloth etc.
The broadband Comb Generator Emitter (CGE) was developed by York EMC Services Ltd for Intel, to facilitate the evaluation of the shielding effectiveness of small enclosures.
There are two models available:
Using this technology, manufacturers will be able to test for emissions shielding performance without having to build a complete system, since the CGE can simulate the emissions of a complete system before the availability of key components.
The CGE is ideal for manufacturers of small enclosures who wish to evaluate their shielding effectiveness in-house e.g. computer chassis manufacturers.
York EMC Services Ltd is able to provide this testing using the CGE on request.
Essentially this test is to determine how “shielded” shielded rooms are!
It involves measurements of shielding attenuation of shielded enclosures (chambers, rooms) in the frequency range 9 KHz to 40 GHz
The test procedure is carried out in accordance with the European standard EN 50147.1
Involving larger equipment, this test is typically carried out on-site.
This testing is aimed at:
A major method for measuring the screening effectiveness of cable screens is the line injection method as detailed in IEC 96-1 and EN 50289-1-6. For cable screens Screening Effectiveness is traditionally expressed as a Transfer Impedance in Ω/m. The line injection method enables measurements of Transfer Impedance up to 3GHz. This is well above the frequency requirements of contemporary standards such as EN 50173-1 and IEC 61156-5, which specify Transfer Impedances up to 30MHz and 100MHz respectively.
A cost-effective method for measuring the screening effectiveness of connectors is the line injection method as detailed in IEC 60512-23-3. As for cable screens, Screening Effectiveness is normally expressed as a Transfer Impedance in Ω/m. The method described in IEC 60512-23-3 is used by the EN 2591-212 standard and is basically the same technique used for testing cable screens. The frequency range for the test specified by IEC 60512-23-3 is 10kHz to 1GHz.
The Reverberation Chamber method of measuring screening effectiveness of connectors is described in EIA-364-66A and is used by military connector standards such as MIL-DTL-38999K. The method allows highly repeatable SE measurements at frequencies between 1GHz and 10GHz.
As a subsidiary company of the University of York, our EMC training services are of a high professional standard, endorsed by the IET.
As part of our EMC Fundamentals of Design and Testing Course, we offer lectures on Shielding as part of the EMC Design Module.
Contact us for more information or to request a quote on any of these services.
Last updated 2010-Mar-30