An Update on Component Shielding Effectiveness Testing Joe Butler Chomerics Division of Parker Hannifin Corp. November 19, 2018

Shielding Effectiveness Commercial EMI Shielding Products EMI gaskets Conductive compounds Conductive coatings Shielded windows and air ventilation panels None of these products are typically measured by an industry consensus, shielding effectiveness test method. Vendor utilized test methods vary by manufacturer.

Shielding Effectiveness Test Standards MIL-STD-285 – Shelters - Withdrawn MIL-DTL-83528 – Conductive Elastomer EMI Gasket Radiated Field and DC Volume Resistivity NSA 65-6, 73-2A, 94-106 – Tempest Shelters IEEE STD 299 – Shelters (replaced MIL-STD-285) IEEE STD 1302 – Guide to EMI Gasket Test Methods ASTM D 4935 – Planar Materials - Withdrawn ASTM E1851 – Shelters (duplicates MIL-STD-285) Reverberation Chamber Tests, TEM Cells SAE ARP 1705 – EMI Gasket Transfer Impedance SAE ARP 1173 – EMI Gasket Radiated Field EN 50147-1 – Anechoic Chambers IEC 61000-5-7 - Enclosures VG 95373 Part 15 – Small Enclosures SCTE 48-1-2006 – GTEM Cell Tests

Shielding Effectiveness EMI Gaskets DC volume resistivity MIL - DTL - 83528 SAE- AIR -1404 warning on relationship between resistivity and shielding effectiveness Transfer impedance SAE- ARP-1705 Radiated field tests MIL-DTL-83528 MIL-STD-285 or IEEE-STD-299 Modified Stirred mode/reverberation chamber testing Enclosure or equipment level testing

Shielding Effectiveness Conductive Compounds DC Volume Resistivity Joint Through-Resistance Radiated Field Tests MIL-STD-285 or IEEE-STD-299 Modified Enclosure or Equipment Level Tests

Shielding Effectiveness Conductive Coatings DC surface resistivity ohms per square @ recommended dry film thickness ASTM D4935 – recently withdrawn Radiated field tests MIL-STD-285 or IEEE-STD-299 Modified Stirred mode/reverberation chamber tests Enclosure or equipment level tests

Shielding Effectiveness Shielded Windows & Air Ventilation Panels Radiated field tests MIL-STD-285 or IEEE-STD-299, Modified Stirred mode/reverberation chamber tests Enclosure or equipment level tests

Shielding Effectiveness Current standards activity IEEE EMC Society actively working on revisions to IEEE STD 299 to create three sections addressing three sizes of enclosures SAE AE-4 Committee has discussed revising and updating SAE ARP 1173 ASTM Committee D09 has stopped EMC standards development activities

Shielding Effectiveness MlL-STD-285 (1956) Frequencies: 150 kHz - 200 kHz, 200 kHz, 1 MHz, 18 MHz, 400 MHz Officially withdrawn but still used in industry Many undocumented/unapproved derivatives used - “modified” MIL STD 285 Used extensively to rate shielding performance of EMI gaskets, conductive coatings, shielded vents and windows 18

Shielding Effectiveness US National Security Agency Standards - NSA 65-6, NSA 73-2A, NSA 95-106 NSA 65-6 (1964) - 1 kHz - 10 GHz,100 dB, 10 kHz - 10 GHz NSA 73-2A (1972) - 1 kHz - 1 GHz, 50 dB, 10 kHz - 100 MHz NSA 94-106 (1994) - 1 kHz – 10 GHz, 100 dB, 10kHz – 10 GHz, (replaced NSA 65-6) 18

Shielding Effectiveness IEEE STD 299 (1991) Frequency range 9 kHz - 18 GHz, (extendable to 50 Hz and 100 GHz) Developed to replace MIL-STD-285 Working group actively working on revisions Standard divided into separate parts for different size enclosures 18

Shielding Effectiveness ASTM E 1851 (1997) Frequency bands - 140 - 160 kHz, 14 - 16 MHz, 300 - 500 MHz, 900 - 1000 MHz, 8.5 GHz - 10.5 GHz Developed by US military shelter manufacturers as replacement for “retired” MIL STD 285 because they felt the proposed replacement, IEEE STD 299, was too complicated 18

Shielding Effectiveness IEC 61000-5-7 (2001) Installation and mitigation guidelines - Degrees of protection provided by enclosures against electromagnetic disturbances (EM code) Frequency range 10 kHz - 40 GHz Establishes shielding code designation - EMABCDEF where ABCDEF indicates 6 frequency bands where a shielding designator value from < 10 dB = 0, to > 100 dB = 9, is assigned 18

Shielding Effectiveness IEC 61000-5-7 Setup

Shielding Effectiveness German VG 95373-15 (1998) Bundeswehr equipment procurement Frequency ranges: 30 Hz - 3 MHz, 30 MHz - 1 GHz Society of Cable Telecommunications Engineers (SCTE) IPS-TP-212 (1996) RF ingress shielding measurement Frequencies: 54 MHz, 100 MHz, 200 MHz, 400 MHz, 700 MHz, 1000 MHz 18

Shielding Effectiveness German VG 95373-15 Setup

Shielding Effectiveness SCTE IPS-TP- 212 Setup

Shielding Effectiveness ASTM D 4935 Test Setup

Shielding Effectiveness ASTM D 4935 Test Samples

Shielding Effectiveness Dual TEM Cell Test Setup

Shielding Effectiveness MIL-DTL-83528 Setup

Radiated Test Setup Chomerics Shielding Effectiveness Test Setup

Radiated Test Setup

Radiated Test Setup

Shielding Effectiveness SAE ARP 1173 Setup

Shielding Effectiveness SAE ARP 1705 Setup

Shielding Effectiveness IEEE STD 1302 Gasket Comparison of Test Methods

Shielding Effectiveness Stirred Mode Chamber

Shielding Effectiveness Some Relevant Reference Papers Stirred Mode – Crawford, Koepke, NBS Tech Note 1092, April 1986; Hatfield, Freyer, Rowan, 1992 & 1994 EMCS Symposium Reverberation Chambers – Holloway, Ladbury, Coder, Koepke, Hill – EMCS Transactions, Reverberation Chambers – Holloway, Ladbury, Koepke, Hill, Garzia – EMCS Transactions, May 2003

Shielding Effectiveness Current Actions of Shielding Component Customers Not only asking for assurances of long term reliability but detailing test protocols to qualify products, e.g., accelerated life testing - high/low temperature cycling, heat/humidity, temperature soak More requesting UL 94 V-0 flammability ratings Increasing amount of individual corporate “Green” initiatives prohibiting certain hazardous substances European Union RoHS requirements Request for detailed elemental composition of materials beyond MSDS details Requests for shielding data against aluminum flanges with trivalent chromate treatment vs. hexavalent chromate

Shielding Effectiveness Future Actions of Shielding Component Vendors Will try to maintain the status quo Will continue to have dwindling involvement in the SE standards development within SAE and IEEE If reverberation chamber shielding test data is necessary, most manufacturers will use outside test labs

Shielding Effectiveness Thanks for your time! Questions??? Joe Butler JButler@Parker.com 781-939-4267 www.chomerics.com