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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.
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Gyrotrons are important in narrowband
HPM production because the only
directed-energy weapon system known
to be fielded today is based on them.
The Active Denial System (ADS) uses a
gyrotron operating at 95 GHz that is
capable of continuous operation. Power
output is 100 kW, and the range is more
than 750 meters. The system uses an
innovative flat parabolic surface {FLAPS)
antenna to radiate a focused beam in a
manner similar to a parabolic dish. The
ADS is effective as a less-than-lethal
weapon for crowd dispersal. The
radiation passes through the
atmosphere with very low loss and is
absorbed in the outer layer of skin,
causing a burning sensation sufficiently Figure 4. Active Denial System With FLAPS Antenna
intense to trigger an involuntary reflex
response in the target. Energy is deposited to a depth of about 0.4 mm. Figure 4 shows
a deployment of the ADS with the FLAPS antenna.
IMPULSE HPM SOURCES
Impulse HPM sources are typically ultrawideband. Microwave generation is
accomplished by charging the antenna, a transmission line, or a tuned circuit directly
with an extremely fast rise-time electrical pulse. This is usually done using a well
designed switch operating in an extremely overvolted condition.
SNIPER
SNIPER (Sub-Nanosecond ImPulsE Radiator) is an SNL HPM source operating at 290 kV
that is capable of greater-than-1-kHz PRR. The peak power in the 3.5-ns-wide pu lse is
1.25 GW, and the rise time is approximately 150 ps, resulting in spectral content from
100 MHz to 1.5 GHz. The radiated field strength, normalized to a distance of 1 meter, is
120 kV/m using a transverse electromagnetic (TEM) horn.
EMBL
EMBL (EnantioMorphic Blumlein) is an SNL HPM source operating at 750 kV that is
capable of 700-Hz PRR. The peak power in the 3.5-ns-wide pulse is 11 GW, and the rise
time is about 200 ps. EMBL radiates a 285-ps impulse with a TEM horn antenna. Its
spectral content extends from 0.2 to 1.2 GHz, with the peak at 800 MHz. The radiated
field strength normalized to a distance of 1 meter is 350 kV/m.
H-SERIES HPM SOURCES
The H-series HPM sources-H2, H3, and HS-were built at the AFRL and used for
various tests of assets. They are all currently inactive, except for a modified version of
H3, which is bei ng used for research at the University of New Mexico. The H-series HPM
sources are all coaxial line pulsers, meaning they contain a pulsed power section that
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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.