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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/ /FOR OFFICIO ls. W&li QNkY AFRL, called the Matrix, is simply a quarter-wave, high-voltage coax line that is switched onto a half-I RA antenna by a high-pressure hydrogen switch. This produces a damped sinusoid with a frequency variable from 180 to 600 MHz by means of different coax line lengths. DIEHL Munitiossysteme in Germany manufactures several mesoband sources for sale to the public. One is a suitcase-sized system using a compact 600-kV Marx generator to provide an impulse to a loop antenna. It is made tunable by changing the size of the loop antenna and can radiate a damped sinusoid at 70 kV/m at 2 meters' distance. BAE Systems in the United Kingdom also sells mesoband sources made using nonlinear transmission lines and solid-state modulators . These are repetition-rate operated to more than 1 kHz. HPM Antennas Many types of antennas are used for radiating HPM signals, and the choice of which to use depends on many factors, including power level, bandwidth, size constraints, efficiency and range requirements, and fratricide concerns. This section discusses the most common antennas used for high-power applications: horns, parallel -plate antennas, and impulse radiating varieties. NARROWBAND ANTENNAS HPM narrowband antennas have typically been extrapolations of conventional types modified in some way to prevent air breakdown and to support higher electric fields. Antenna arrays are in development, albeit mainly for phase-locked multioscillator systems. The obstacle to using arrays in single-oscillator systems is that little has been done to develop the required antenna subelements (phase shifters and phase splitters) capable of high-power operation. Eventually, however, antenna arrays will be dominant in narrowband HPM because higher powers will require larger area antennas to prevent breakdown and arrays are the only antennas that are compatible with electronic control for tracking targets. To achieve good effectiveness and gain, the array size should be larger than the wavelength to be radiated. The beam width is approximately 2A/L, and the gain is L2/V . Also of importance is the separation between elements in the array. Larger distances between elements cause grating lobes offcenter from the main beam. If the distance between elements can be reduced to less than the wavelength, grating lobes will be minimal. In practice, however, breakdown constraints make this hard to accomplish. In practice, only a very small number of antenna types have been used in narrowband HPM with any success. By far the most common type is the horn in its many forms, including transverse electromagnetic (TEM), pyramidal, and conical. One advantage of horn antennas for narrowband use is that the radiation pattern and the gain can be calculated precisely. For TEM and pyramidal horns, the gain is given by: G = 2nab/A2 UNCLASSIFIED/ /fOR. 8ffl@IAI:: W&lii 8PUzlf 25
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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.