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EMC- Military and AerospaceRadiated Immunity Concerns

Current Events: August 2010

Boxborough – 19 August 2010

Michael Koffink

Operations Manager, EMC

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Military/Aerospace EMC

The gap between the test requirements of commercial-off-the shelf equipment (COTS) and military/aerospace requirements is not an easy bridge to cross. This is true in regards to EMC and other environmental test requirements.

This is mainly because of the severe environments these devices and systems may be exposed to. Besides extreme weather conditions, temperatures, physical shock and vibration, extreme EMC environment is considered a major threat to performance of equipment.

For this reason EMC testing requirements are considered more stringent in the military/aerospace world than is found in the commercial world often posing difficulties for manufacturers wanting to offer their products in both arenas

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Some Differences Between Commercial and Military/Aerospace Test Requirements

• Radiated Test Distance- Commercial 3m or 10m common. Military/Aerospace is 1m.

• Radiated Emissions Configuration- Commercial use of a turntable and adjustable antenna heights. Military/Aerospace uses fixed position methodology.

• Lower and Higher frequency ranges covered by Mil/Aerospace.

• Much higher Immunity field strengths- Commercial 3V/m and 10v/m is typical. Mil/Aerospace 200V/m and up is typical on shipand airborne equipment

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Standards

• MIL-STD-188-124Grounding, Bonding and Shielding for Common Long Haul/Tactical Communications Systems Including Ground Based Communication-Electronics Facilities and Equipment

• MIL-STD-188-125-1High-Altitude Electromagnetic Pulse (HEMP) Protection For Ground-Based C41 Facilities Performing Critical, Time-Urgent Missions - Part 1 - Fixed Facilities

• MIL-STD-188-125-2High-Altitude Electromagnetic Pulse (HEMP) Protection For Ground-Based C4I Facilities Performing Critical, Time-Urgent Missions - Part 2 - Transportable Systems

• MIL-STD-331CEnvironmental and Performance Tests for Fuse and Fuse Components

• MIL-STD-449DMeasurement of Radio Frequency Spectrum Characteristics

• MIL-STD-461FRequirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

• MIL-STD-464A Electromagnetic Environmental Effects – Requirements for Systems

• MIL-STD-704FAircraft electric Power Characteristics

• MIL-STD-1310HShipboard Bonding, Grounding, and other Techniques for Electromagnetic Compatibility, Electromagnetic Pulse (EMP) Mitigation, and Safety

• MIL-STD-1377Measurement of effectiveness of cable, connector, and weapons enclosure shielding and filters in precluding Hazards of electromagnetic radiation to ordnance

• DOD-STD-1399-70-1Interface Standard for Shipboard Systems – Section 070 – Part 1 – DC Magnetic Field Environment

• MIL-STD-1399-300BInterface Standard for Shipboard Systems – Section 300 - Electric Power, Alternating Current

• MIL-STD-1541AElectromagnetic Compatibility Requirements for Space Systems

• MIL-STD-1542BElectromagnetic Compatibility and Grounding Requirements for Space System Facilities

• MIL-STD-1576Electroexplosive Subsystem Safety Requirements and Test Methods for Space Systems

• MIL-STD-1605AProcedures for Conducting a Shipboard Electromagnetic Interference (EMI) Survey (Surface Ship)

• MIL-STD-2169BHigh Altitude Electromagnetic Pulse (HEMP) Environment.

• DO-160 F Environmental Conditions and Test Procedures for Airborne Equipment

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Most Common Standards in Regards to EMC

• MIL-STD-461FRequirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment

• MIL-STD-464A Electromagnetic Environmental Effects –Requirements for Systems

• DO-160 F Environmental Conditions and Test Procedures for Airborne Equipment Sections

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Mil-Std 461 F

• Most widely used standard for US Military EMC assessment

• Specific test requirements are grouped according to test type ”RS”-Radiated Susceptibility “RE- Radiated Emissions “CS” Conducted Susceptibility “CE” Conducted Emissions

• Test applicability based on which platform the equipment will be used on. ie ground, ship, airborne

• ESD and Lightning testing is not covered under current and past versions however it is being considered for future version “G”

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RTCA DO-160F

• DO 160 is the most widely used standard to specify test conditions for the design of avionics electronic hardware in airborne systems.

• Large document that covers all test requirements not just EMC.

• Test types broken out by section.

• Includes requirements for lightning. Both near effect and direct.

• ESD requirments

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Mil-STD 461 Radiated Susceptibility

RS 101 – Magnetic Field 30 Hz to 100KHz

RS 103- Electric Field 2MHz to 40GHz

RS 105- Transient Electromagnetic Field

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Mil-Std 461 RS 103

• ALSE and Reverberation chambers methods allowed

• 2MHz to 40GHz(18 to40GHz optional)

• 200V/m for aircraft and ships above deck

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DO 160 Section 20 Radiated Susceptibility

• ALSE and Reverberation chambers methods allowed

• 10KHz to 400MHz coupled by injection probe “CS”

• 100MHz to 18 GHz radiated by antenna

• Field strength requirements guided by category

• Categories S,T,W,Y rang 1 to 200V/m

• HIRF categories high field strength both CW and pulse required

• Category G up to 3000 V/m pulsed

• Category L up to 7200 V/m pulsed

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Tips

• Understand the environment the product maybe used , what are the risks? Standards can be tailored to fit application.

• Try not to “just get by”

• Expect to ruggedize your product in terms of shielding and overall design.

• Large systems may need to be illuminated in multiple spots or may require reverb method

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EMC2GR Initiative

• Demands of our clients and the local aerospace market in the Grand Rapids MI area has allowed Intertek the opportunity to grow and add EMC capabilities to our Kentwood MI facility!

• Coming soon September 2010

• Mil/Aerospace, Commercial, Automotive

• 4 EMC chambers, 2 Mils std, 1 full ANSI height 3M, 1 Reverb

• Level 5 DO 160 Lightning induced transients

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Questions?