EMC Laboratory

Aerospace/Defence Electronics Electromagnetic Compatibility (EMC) Testing

Civil and military EMC specifications require that today's electronic systems undergo formal evaluations of their radiated and conducted emissions, as well as their susceptibility to radiated and conducted electromagnetic interference. The objective for these systems is to reduce their undesired emissions to specified limits, and design them to be immune to external influences. Our goal is 'compatibility', or the ability of electronic equipments and systems to co-exist without mutual interference.

The Faraday Test Centre services enable the total electromagnetic spectrum to be measured to certified standards. Capabilities include test plan and test report origination, type approval/qualification testing, and development testing and interference suppression. The centre’s comprehensive service tests for:

• Compass-safe distance
• Electromagnetic pulse/transients
• Electromagnetic discharge
• Radiated emissions (20Hz to 40GHz)
• Conducted emissions (20Hz to 1GHz)
• Radiated susceptibility/immunity (20Hz to 40GHz)
• Conducted susceptibility/immunity (20Hz to 400MHz)

Explanation of EMC Methodology

Conducted emission/interference is conducted over the power and data/signal leads to equipment. Radiated emission/interference is directly radiated from energised equipment or associated leads. Interference is caused by changes of electric current. The greater the rate of change of current, the greater the amount of energy at the upper frequency end of the spectrum.

A shielded room is necessary to prevent interference with the surrounding environment, and to ensure a measurement area devoid of external influences, such as fluorescent lights, rectifiers, local radio and TV transmissions, and mobile telephone transmitters.

Normally, the conductive walls in the screened rooms drastically distort the antenna and test item radiation patterns, and the radiation path attenuation. Therefore, in order to reduce the uncertainty of the measured or applied field, the walls, floor and ceiling are lined with ferrite tiles and/or carbon-loaded anechoic absorber material.

EMC Facilities

The EMC test laboratory has two anechoically lined screened rooms, five non-anechoic screened rooms, and a mode stir, high-field strength reverberation chamber.

The facility covers the test frequency range of DC to 40GHz for radiated emission and susceptibility tests. Field strengths are available up to 2000V/m.
This laboratory also conducts tests using electromagnetic pulses (damped sine wave), and there is an additional transient test area catering to DC/AC voltage transients, AC frequency transients, and variations. These tests are performed using a programmable solid-state transient and power interrupt supply for powers up to 3KVA single-phase or 1KVA three-phase power. The largest chambers are 8.5m long by 7.5m wide by 4.2m high. The access door is 3.0m wide by 3.5m high. Adjacent to each screened room is a shielded control/test equipment room.