Power line filters safeguard EMC test chambers
– June 2022
MPE’s power line filters provide very high insertion loss performance (dB against frequency in Hz) across the full frequency spectrum from Very Low Frequency (VLF) to Super High Frequency (SHF).
In most situations nowadays systems must be available 24 hours a day, seven days a week and operate safely and securely without any interruption in service due to interference. That is no more so than in the universe of EMC test chambers. Such specialised chambers test electronic devices against regulatory standards applicable to both radiated and conducted radio frequency emissions and immunity. We may be talking about anechoic chambers for antenna testing or for automotive NVH (Noise, Vibration, Harshness) and performance testing – or indeed those in the world of satellite communications and broadcasting. Accordingly, integrated high-current MPE filters provide essential EMC protection for incoming power lines on RFl-shielded test chambers designed in-house, manufactured and installed by NTD Shielding of St Helens. Merseyside. As an example, during 2019 NTD Shielding Services installed and commissioned a high performance RF chamber for the BBC. This was at BBC Research &. Development’s South Laboratory, The Lighthouse, at Wood Lane, Shepherd’s Bush, West London.
External view of the RF I-shielded test chamber designed, manufactured and installed by NTD Shielding Services for BBC Research & Development’s South Laboratory at Shepherd’s Bush, west London
The high-performance chamber, which they installed for the BBC measures 2.4m high x 2.4m long x 3.6m wide and incorporates a full electrical package with fibre-to-data conversion. Within this system MPE filters were vital to provide protection and electrical immunity for the incoming power lines. a Vesda fire detection system and a “test-in-progress” status warning light. MPE’s EMC filters were specified to ensure the high efficiency of the RFI shield and also the EMC compliance of the whole electrical system and each of it’s incoming lines. The power line filters manufactured by MPE for this application provide l00dB of insertion loss performance across a full frequency range extending to over 20GHz. A variety of MPE filters for up to 32A current were required to meet the demands of the application.
In another set of applications. NTD Shielding Services installed three bespoke chamber solutions for Isotropic Systems at Reading. each incorporating MPE’s high-performance EMC filters. A pioneer in the satellite communications market. Isotropic Systems has a host of ambitious new satellite constellations from SESl.n marsat. SpaceX. OneWeb. Telesat and Amazon currently being developed and deployed in conjunction with GEO HTS assets. Central to these development programs. Isotropic required a high-performance inhouse EMC testing capability as a critical resource. NTD Shielding Services installed the three bespoke chambers between January and March 2020. with commissioning completed shortly afterwards. In support of these works MPE supplied a range of its high-performance filter solutions. including extended performance variants. which provided high levels of attenuation through to 40GHz.
So the first chamber at Isotropic Systems measured 4.5m high x 9.5m long x 4.5m wide. featuring double access doors. access ramps and fire detection systems. with integral 16A and 32A extended performance filters from MPE. Measuring an equally impressive 3.5m high x 10.5m long x 3.5m wide. the second chamber was equipped with semi-automatic pneumatic doors. USB ports. a media conversion pack and fire detection systems. Again MPE’s 32A filter solutions were utilised. Completing the installation was a 40GHz ultra-performance, millimetre wave. mobile chamber. measuring 1.3m high x 2.Sm long x l.3m wide incorporating MPE’s DC filter solutions. MPE’s EMC filters were specified on all three applications at Isotropic Systems to ensure the high performance of each EMC chamber and also the EMC compliance of each electrical system and its incoming lines. In this case the power line filters manufactured by MPE provide l00dB of insertion loss performance across a full frequency range to more than 40GHz.
The three bespoke EMC test chambers manufactured by NTD Shielding Services and installed at Isotropic Systems, Reading
Shown here is a Eurofighter Typhoon under EMC test in anechoic chambers manufactured and installed by MVG. MPE power line filters are fitted at the power inlets of these test chambers to shield them against EMI and RFI interference. At Horiba MIRA in Nuneaton. Warwickshire. MPE upgraded the protection on a chamber to meet the requirements of the electric vehicle market. MPE delivered both AC and DC filters. with the DC filter providing a very high attenuation performance of lO0dB from l0KHz through to 18GHz and being rated for 800A at up to 1500V DC.
Whilst the chamber itself measured around 20m x llm x 7.5m. the available space for any new filters was of primary concern. as was the overall increase in weight to the existing structure from the filters. MPE therefore adapted designs from its high-current DC filter catalogue range, thereby ensuring that envelope size and weight limits were met. MPE also designed and delivered custom busbar configurations and custom enclosure hardware for both external and internal mounting to the existing structure. The result was a smooth and efficient filter installation. minimising the need for MIRA to make changes to its existing chamber.
Eurofighter Typhoon under EMC test in an anechoic chamber manufactured and installed by the Microwave Vision Group (MVG)
