IEMI refers to the deliberate attempt to produce EMI to interfere with commercial equipment.
Dr. William A. Radasky, Ph.D.
Metatech Corporation, Goleta, CA
Over the past few years several articles have been written by this author and others indicating the threat and importance of intentional electromagnetic interference (IEMI).1–4 Since the publication of the Interference Technology Annual EMC Guide in 2004, work has continued at a sustained rate with several major events occurring in the field. These include the presentation of important papers at the EUROEM 2004 Conference in Magdeburg, Germany in July 2004, and the publication of a special issue on IEMI and HPEM (high power electromagnetics) by the IEEE EMC Society in August 2004. Additionally, IEC SC 77C has continued to move forward in this area by publishing several important documents and in planning to produce additional IEMI publications in the future. These activities will be summarized and referenced in this article.
To refresh the reader regarding the terminology employed here, the term IEMI refers to the deliberate attempt to produce electromagnetic radiated and conducted disturbances to interfere with the operation of commercial equipment. This could be done for criminal or terrorist purposes, although the purpose of the technical work is to determine the feasibility of such attacks and to determine ways to detect an attack and/or to protect against the types of disturbances that might be generated.
EUROEM 2004 CONFERENCE IN MAGDEBURG, GERMANY IN JULY 2004
From July 12–16, 2004, the premier worldwide high power electromagnetics conference was held in Magdeburg, Germany—EUROEM 2004. This conference covered several areas of interest including the effects of high power electromagnetic fields on electronic systems, the design and application of ultrawideband sources and antennas, and methods to use high power electromagnetic fields to detect unexploded ordinance.
Of interest to those of us working in the field of IEMI was a special session organized by William Radasky and Manuel Wik to examine IEMI Protection Methods. Eight papers were presented in the session and are listed below as numbered in the book of abstracts:5
14-1 Radasky, W., “Protection Approach for Commercial Buildings Against Intentional Electromagnetic Interference (IEMI).”
14-2 Siniy, L.L., V. Efanov, V. Fortov, Y.V. Parfenov, L. Zdoukhov, “Technical Means to Study an Immunity of Infrastructure Objects to Intentional Electromagnetic Interference.”
14-3 Parfenov, Y.V., L. Zdoukhov, W. A. Radasky, “Research Concerning the Influence of Ultrawideband (UWB) Electromagnetic Fields on Electronic Cash Machines.”
14-4 Hoad, R., D. Herke, S.P. Watkins, “Electromagnetic Interference Related Susceptibility of COTS Network Components.”
14-5 Jeffrey, I., C. Gilmore, J. LoVetri, “The Impact of HIPDI as Related to 100BaseTx Internet.”
14-6 Prather, W.D., Electromagnetic Protection—Shielding Specification Techniques and Measurement Methods.”
14-7 Thottappillil, R., R. Montano, D. Mansson, “Response of Surge Protective Devices to Very Fast Transient Conducted Pulses.”
14-8 Recht, E., T. Naxon, A. Cohen, “UG Filtering—An Effective Technology Against IEMI and HPM.”
While it is not possible to review all of these papers in detail, several points are of particular interest. Paper 14-1 described the relationship between high-altitude electromagnetic pulse (HEMP) and IEMI and the effectiveness of particular protection approaches for both threats. Paper 14-2 described EM experiments with infrastructure systems to determine their vulnerability to different types of radiated and conducted threats. Paper 14-3 was particularly interesting in that it examined the vulnerability of cash machines to relatively low level UWB field threats such as those that could be produced by very small sources. Figure 1 provides a summary of some of the data presented in this paper.
Paper 14-4 examined the impact of CW EM fields on PCs and simple networks. It was found that the presence of a network reduces the field levels required to upset computer equipment and that relatively low EM fields are needed to create a denial of service situation. At higher levels of fields, severe disruptions could occur in which permanent damage of some of the electronics was found. Paper
14-5 examined the impact of IEMI on communications by the introduction of interference that could create a problem for error-correction software. Using special schemes to introduce the interference, complete disruption of a communications channel was possible at relatively low levels of the interference field.
Paper 14-6 examined shielding methods typically used for aircraft in the past and their possible use in the future for the IEMI threat. Paper 14-7 presented the performance characteristics of low voltage surge protection devices when faced with fast transient conducted pulses. Paper 14-8 proposed some new filtering technologies against IEMI threats for frequencies up to 10 GHz. These filters can easily be integrated into connectors to achieve high levels of EM protection.
SPECIAL ISSUE OF IEEE EMC TRANSACTIONS ON HIGH-POWER ELECTROMAGNETICS (HPEM) AND INTENTIONAL ELECTROMAGNETIC INTERFERENCE (IEMI)—AUGUST 2004
This special issue of the IEEE EMC Transactions6 was developed to cover the emerging field of IEMI and its context within the overall field of HPEM. Sixteen papers were published in five sub-disciplines, and the paper titles are listed below.
Introduction to the Special Issue
1. Radasky, W.A., C.E. Baum, M.W. Wik, “Introduction to the Special Issue on High-Power Electromagnetics (HPEM) and Intentional Electromagnetic Interference (IEMI).”
Environments and Test Capabilities
2. Giri, D.V., and F.M. Tesche, “Classification of Intentional Electromagnetic Environments (IEME).”
3. Sabath, F., M. Bäckström, B. Nordström, D. Sérafin, A. Kaiser, B.A. Kerr, D. Nitsch, “Overview of Four European High-Power Microwave Narrow-Band Test Facilities.”
4. Prather, W.D., C.E. Baum, R.J. Torres, F. Sabath, D. Nitsch, “Survey of Worldwide High-Power Wideband Capabilities.”
Coupling to Cables and Systems
5. Haase, H., T. Steinmetz, J. Nitsch, “New Propagation Models for Electromagnetic Waves Along Uniform and Nonuniform Cables.”
6. Carlsson, J., T. Karlsson, G. Undén, “EMEC—An EM Simulator Based on Topology.”
7. Parmantier, J.-P., “Numerical Coupling Models for Complex Systems and Results.” IEMI Effects on Equipment, Systems and Communications
8. Camp, M., H. Gerth, H. Garbe, H. Haase, “Predicting the Breakdown Behavior of Microcontrollers under EMP/UWB Impact Using a Statistical Analysis.”
9. Nitsch, D., M. Camp, F. Sabath, J.-L. ter Haseborg, H. Garbe, “Susceptibility of Some Electronic Equipment to HPEM Threats.”
10. Hoad, R., N.J. Carter, D. Herke, S. P. Watkins, “Trends in EM Susceptibility of IT Equipment.”
11. Bäckström, M.G., K.G. Lövstrand, “Susceptibility of Electronic Systems to High-Power Microwaves. Summary of Test Experience.”
12. Parfenov, Y.V., L.N. Zdoukhov, W. A. Radasky, M. Ianoz, “Conducted IEMI Threats for Commercial Buildings.”
13. Jeffrey, I., C. Gilmore, G. Siemens, J. LoVetri, “Hardware Invariant Protocol Disruptive Interference for 100Base-Tx Ethernet Communications.”
Protection, Measurements and Standards
14. Weber, T., R. Krzikalla, J.-L. ter Haseborg, “Linear and Nonlinear Filters Suppressing UWB Pulses.”
15. Weber, T., J.-L. ter Haseborg, “Measurement Techniques for Conducted HPEM Signals.”
16. Wik, M.W., W.A. Radasky, “Development of High-Power Electromagnetic (HPEM) Standards.”
Paper 1 introduces the entire issue and provides some background concerning the entire field of work. Papers 2 through 4 provide definitions of the different types of EM environments that may be produced and indicate the simulator capabilities that exist worldwide to simulate these types of waveforms.
In the coupling area, there are 3 papers (5-7) that deal with new developments in analytic and numerical analysis that can be useful in solving IEMI coupling problems. With regard to equipment and system effects arising from intentional EM environments, papers 8 through 11 cover the effects from the component level, to the equipment level, to the system level. In addition to the effects of EM fields on electronic systems, one also finds a discussion concerning the threat of conducted environments to equipment inside of buildings (paper 12). Finally, there is a detailed discussion of the impact of IEMI on communication channels (paper 13).
The special issue concludes with 3 papers dealing with protection methods and standardization (14-16). The entire issue is an important resource for those interested in understanding the importance of IEMI and also for those who wish to contribute to this area of technology in the future.
IEC SC 77C (EMC: HIGH POWER TRANSIENT PHENOMENA)
Over the past year, the IEC has made significant progress on three documents that are intended to provide important IEMI information to the users of standards. The three documents deal with the effects of high power electromagnetics in general and IEMI in specific, the categorization of the IEMI environments, and measurement methods for HEMP and IEMI. These publications are listed below.
61000-1-5, “High power electromagnetic (HPEM) effects on civil equipment and systems,” published as a technical report, November 2004.
61000-2-13, “High power electromagnetic (HPEM) environments—radiated and conducted,” has been approved at the Final Draft International Standard (FDIS) level and is expected to be published as a standard in the summer of 2005.
61000-4-33, “Measurement methods for high-power transient parameters,” has been approved at the CDV level and is awaiting the French translation before being issued as an FDIS. It is expected that this standard will be published in late 2005.
At a recent meeting of several SC 77C project teams in Lausanne, Switzerland, it was recommended that the next phase of work in the IEC would include several new documents (a-c) and one updated document (d):
(a) Compendium of worldwide HPEM test facilities
(b) System level susceptibility assessment methodology for HEMP and HPEM
(c) The impact of HEMP on the distributed infrastructure
(d) Protection concepts for HPEM (Addition of information to IEC 61000-5-6)
According to the rules of the IEC, new work item proposals will be submitted to the National Committees to determine their interest in this new work and to determine if sufficient experts are available to accomplish the work.
It has become increasing clear that while EM hardening could have value to protect commercial equipment from an IEMI attack, the role of monitoring is quite important. In the past this author has indicated that work had progressed to develop monitors that could detect IEMI signals on wiring within a building; recently a new monitor has become available to detect radiated fields.
This new monitor is known as the “Canary”, and it has been developed by QinetiQ in the UK.7 The most important aspect of this mobile detector (battery-powered) is that it can detect radiated fields that are continuous wave signals or fast repetitive pulses. The detection frequency range is between 10 MHz and 8 GHz, with the ability to detect repetitive pulses with pulse widths wider than 300 ps. In addition, the detectability level is as low as 1 mW/m2. Figure 2 presents a photograph of the sensor.
With the continuing progress in this new field, IEMI protection services, including the new developments described above, are being offered to help installations cope with this new threat.8 It should be noted that the protection against IEMI also provide other benefits including an increase in the immunity of an installation to other related EM disturbances.
 W.A. Radasky. “What Is Intentional Electromagnetic Interference (IEMI) and What Can We Do About It?” ITEM. April 2003.
 W.A. Radasky. “An Update on Intentional Electromagnetic Interference (IEMI).” Interference Technology. April 2004.
 W.A. Radasky, M.A. Messier, M.W. Wik. “Intentional Electromagnetic Interference (EMI)—Test Data and Implications.” 14th International Zurich Symposium and Technical Exhibition on EMC. February 2001.
 W.A. Radasky, M.W. Wik. “Intentional Electromagnetic Interference (IEMI)—Understanding the Threat and Developing Protection Concepts.” 15th International Zurich Symposium and Technical Exhibition on EMC. February 2003.
 “Book of Abstracts for EUROEM 2004.” EUROEM 2004 Conference, Magdeburg, Germany. 12–16 July 2004.
 “Special Issue on High-Power Electromagnetics (HPEM) and Intentional Electromagnetic Interference (IEMI).” IEEE Transactions on EMC, Vol. 46, No. 3. August 2004.
 “The Canary EM Detector.” QinetiQ. Farnborough, UK. For further information contact Richard Hoad at [email protected]
 “EM Protection Services.” www.metatechcorp.com.
ABOUT THE AUTHOR
William A. Radasky received the B.S. degree with a double major in Electrical Engineering and Engineering Science from the U.S. Air Force Academy in 1968. He also received the M.S. and Ph.D. degrees in Electrical Engineering from the University of New Mexico in 1971 and the University of California, Santa Barbara in 1981, respectively.
He started his career as a research engineer at the Air Force Weapons Laboratory in Albuquerque, New Mexico working on the theory of the electromagnetic pulse (EMP). In 1984, he founded Metatech Corporation in Goleta, California where he is currently President and Managing Engineer. During his 37-year career, he has published over 300 technical papers and reports dealing with electromagnetic interference (EMI) and protection.
Dr. Radasky’s current interests include studies to understand the threat of Intentional EMI and to develop mitigation and monitoring methods to protect facilities from this new threat. He is Chairman of IEC Subcommittee 77C, which is developing high-power electromagnetic protection and test standards for civil systems. He is also the Chairman of TC-5 (High Power EM) for the IEEE EMC Society. Other IEMI activities include his role as Associate Editor for the IEEE EMC Transactions special issue on IEMI and as chair of the IEEE Standards Working Group to provide protection guidelines for publicly accessible computers from the threat of IEMI. In addition he is the Chairman of the IEC Advisory Committee on EMC (ACEC), which is tasked with coordinating all EMC standardization work for the IEC. He is an EMP fellow and a member of the Eta Kappa Nu and Tau Beta Pi honor societies. In October 2004, he was presented the Lord Kelvin Medal in Seoul, South Korea by the International Electrotechnical Commission for exceptional contributions to international standardization.