Measurement Testing

Mjr · Site Admin Joined: 13 Jul 2005 Posts: 294

The University of York, EMC Services division offers tests for gauging Shielding Effectiveness in different environments and materials. They include:

Electromagnetic Shielding Effectiveness of Planar Materials

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.

Small enclosures test using purpose built CGE

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:

* CGE 01 ranging from 100MHz to 12GHz
* CGE 02 ranging from 250MHz to 26GHz

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.

Anechoic Chambers: Shield Attenuation Measurement

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:

* Manufacturers of anechoic chambers, screened rooms, GTEM cells.
* Test laboratories who want to validate the shielding effectiveness of their screened room

Cable Screen Test

A major method for measuring the screening effectiveness of cable screens is the line injection method. 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 EN50173-1 and IEC61156-5, which specify Transfer Impedances up to 30MHz and 100MHz respectively.

Connector Screen Test

A major method for measuring the screening effectiveness of connectors is the line injection method. Frequency range for the test specified by IEC 60512-23-3 is 10kHz to 1GHz.

For more info, contact:
http://www.yorkemc.co.uk/

Tel: +44 (0)1904 434440
Fax: +44(0)1904 434434
E-mail: enquiry@yorkemc.co.uk

York EMC Services Ltd
University of York
Heslington
York
YO10 5DD
United Kingdom