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This Defense Intelligence Reference Document (DIA-08-0912-005) is dated 28 January 2010. The Defense Intelligence Agency's Defense Warning Office prepared it under the Advanced Aerospace Weapon System Applications Program. It gives an overview of pulsed high-power microwave sources and the technologies needed to build them, including insulation, cathode materials, high-voltage switching, pulse generators and antennas. The paper concludes that progress requires better cathodes, switching and insulation, and that compact ultrawideband antennas will remain difficult to build.
From the source: Release of 2026-09-18 Incident: 1/28/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys pulsed high-power microwave (HPM) source technology and argues that such systems remain of military interest because they can disrupt or damage electronic systems with short, intense electromagnetic pulses. The report reviews the main source types and the supporting technologies they depend on, including high-voltage insulation, switching, cathode materials, antennas, and pulse-power generation. It emphasizes the difficulty of building systems that are compact, efficient, and practical to field, since short pulse durations, antenna size, heating, detectability, and beam or signal quality all impose hard engineering limits. Its overall conclusion is that the technology has significant potential military value, but that further progress depends on advances in cathodes, predictive modeling, high-speed high-voltage switching, and low-loss insulation, while compact ultrawideband systems will remain difficult because of basic physical constraints on antenna design.
UNCLASSIFIED/ ,'FOlt err1e1At YSI!! 8,.LY a PRR is applied such that there is insufficient time for thermal diffusion between pulses (about 1 millisecond), then there will be an overall constant rise in temperature. For this reason, the PRR capability is of extreme importance for any HPM source. As a matter of course, assets to be tested include those of friend and foe alike, the goal being to find vulnerabilities in both and correcting those found in our own assets. Several techniques are employed to mitigate vulnerabilities found in assets, including filtering of conductor lines, using metallic enclosures, eliminating any unnecessary openings in the outer enclosure, and using ferrite or other magnetic materials. Any electronics inside a completely sealed metallic container (Faraday cage) would have no vulnerability to HPM of any variety; however, such a scenario is also of little or no use, since there could be no communication to or from the enclosure. Assets therefore must include some openings for communications, instruments, air flow, and sensors, sometimes as a matter of fulfilling their function. From the HPM source perspective, care must be taken to prevent fratricide and harm to friendly assets. To prevent fratricide, all connections to the source must be filtered to prevent fast transients from returning to the control unit. Some signals can be transmitted using fiber-optic cable; however, there is usually a piece of equipment at the source end that must be filtered. Some connections, such as the high-voltage power supplies, can make good use of high inductance filtering to eliminate fast transients, while others, such as trigger lines, must make use of other filtering means, such as transformer coupling, lightning arrestors, transorbs, and fast-acting, high-voltage diodes. Preventing harm to friendly assets is difficult and is a major reason why HPM has rarely been employed in actual battlefield settings. To ensure there is no harm to friendly assets, all assets would have to be tested for vulnerabilities, something that is not done at present. The antenna is a major factor in this matter. Unfocused antennas radiate a pattern that spreads as it progresses outward and, thus, the area subjected to the EM fields increases with distance. It is then harder to separate one's own assets from the radiated fields. In addition, it is very difficult to detect these sort of pulsed sources, since the pulses are very short (typically 1-500 nanoseconds), and even in burst mode, the bursts are usually less than 10 seconds. The short burst mode operation is necessary because of the high peak powers and subsequent heating of key components such as switches. The UWB sources would be the most difficult to detect, since they have nearly zero energy at any one frequency and so would not be detected at all by instruments such as spectrum analyzers. UNCLASSIFIED/ ,creR 8FFl@IAL U:!I! ()fl[ I viii
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 37 pages are in the text index: search them above, or from the library's search.