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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/ /FOlil OFFl&IAl WSE 8,.lV section on laminated insulation). Many plastics come in a wide variety of shapes, forms, and grades, including bulk volumes, a variety of sheet thicknesses, and various rod diameters. The subject of using plastics as insulation fills volumes in reference books and has yet to be exhausted . Table 1 shows selected dielectric properties, collected over several years, on some of the most common plastics for high-voltage use. Table 1. Dielectric Properties of Some HPM Plastics Material Trade Name Breakdown Voltage (kV/mil) Acetal Delrin 4.0 Polypropylene 6.0 Polyetherim ide Ultem 7.0 Polysulfone Ultrason S 7.5 Polyethersulfone Ultrason E 5.8 Polycarbonate Lexan 6 .3 Polvohenylene Ether Noryl 0.6 Polyphenylene Sulfide Ryton 0.4 Polyethylene 5.0 Polyvinylch loride 1.8 Epoxies One of the greatest advantages of casting epoxies is that a high dielectric strength can be attained with low maintenance, a long shelf life, and ease of transportation compared with liquid or laminated insulation schemes. Some of the best epoxies ever used for high-voltage insulation have only recently become available. These advancements are due mainly to efforts by the automotive industry to miniaturize the ignition coil to the point where a separate coil could be incorporated into the spark plug cap at each cylinder. Technologies have been devised for casting several varieties of epoxy to allow larger volume castings. The goals are to minimize voids and bubbles, deal with any exothermal effects, and reduce shrinkage. In addition, a good candidate material for high-voltage casting must have a high dielectric strength at the frequencies required, a long pot life, good adhesion, and an unlimited cure depth at a low temperature. With many epoxies, shrinkage and the glass transition point are functions of the cure temperature. New, state-of-the-art epoxies have several desirable characteristics never before available in a sing le product that make them ideal for high voltage applications. Two such characteristics are a low viscosity at room temperature and a long pot life. This means the epoxy can be mixed (resin and hardener) and the unit to be insulated can be filled under vacuum to eliminate voids and bubbles. Some of these epoxies have the viscosity of milk at about 100 degrees Fahrenheit and a pot life of several hours. A third desirable characteristic is a very low, almost imperceptible exotherm. Th is allows insulation of items sensitive to heat, such as thin plastics, paper, and electronic components or integrated circuits . A fourth desirable characteristic is low shrinkage, even in large castings. This allows insulation of regions where dimensional stability is important, such as at distances from high-voltage sections and resonant structures. A fifth desirable characteristic is good adhesion, both to itself and to components to be insulated. This is important because any separation from a component creates a void region where the dielectric strength will be compromised. UNCLASSIFIED//5OB OFFICIO ls. U&'li QPlls.¥ 3
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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.