1. RADIATION SOURCES: OUTPUT POWER vs. FREQUENCY

3. GYROKLYSTRON
The development of the millimeter-wave Ka-band (34-36 GHz)
and W-band (93-95 GHz) gyroklystrons was primarily stimulated
by radar applications within the ranges of the atmospheric RF windows.
Later, high power pulse gyroklystrons attracted attention as sources
of coherent radiation for compact, high gradient linear accelerators.
Pulsed 35 GHz two-cavity gyroklystron developed in IAP(1993)
pulse length μsec
max power kW
max efficiency % at P = 300 kW
gain dB at P = 600 kW
instantaneous bandwidth at -3 dB %
The bandwidth is limited by the Q-factor of the output cavity, which is about 320.

4. High average power four-cavity W-band (94 GHz) gyroklystron
developed jointly by NRL, the University of Maryland, and
industrial companies Litton and CPI (1999)
Over 10 kW average power with 11% duty cycle
(100 μsec pulse, 1.1 kHz repetition rate)
instantaneous bandwidth at – 3 dB MHz (0.5%)
Gain dB
Efficiency %

5. High Power 95 GHz Gyro-Devices with Permanent or Solenoid Magnets
PROBLEM STATEMENT
Non-lethal weapons provide a less-than-lethal option that give war fighters the time and distance to better determine someone’s intent or make individuals comply without having to resort to deadly force.

6. The Active Denial System (ADS) is a counter-personnel, non-lethal, directed-energy weapon that can help troops fill the gap between shouting and shooting.
It provides numerous advantages over existing non-lethal weapons, such as extended range and extremely small risk of injury.

7. The ADS produces millimeter waves at a frequency of 95GHz and uses an antenna to direct a focused, invisible beam toward a designated subject. Traveling at the speed of light, the energy strikes the subject and reaches a skin depth of only about 1/64th of an inch, or the equivalent of three sheets of paper.
It produces a heat sensation that within seconds becomes intolerable and forces the targeted individual to instinctively move.
TECHNOLOGY FEATURES
A compact high average power millimeter wave gyrotron at 94 or 95 GHz
that uses a normal magnet of low operating power has important applications
for Area Denial Technology and Systems (ADT, ADS), communications,
radar, particle accelerators, materials heating and processing,
and more, at lower cost.

8. Gyroklystron Design Summary
50 MW 30 GHz gyrklystron amplifier for testing of high gradient accelerator structures at K and Ka bands
Gyroklystron Design Summary
Estimate Development Cost and Schedule
• $750,000
• Two years

9. Sources for radar and communications systems
Recent advances in radars are based on the development of
two classes of HPM sources:
high-peak power, short-pulse (ns) sources
longer pulse (s) millimeter-wave sources
Nanosecond Gigawatt Radar
10 GHz, 0.5 GW, 5 ns, 150 Hz, 3° beam width
Moving targets of ~1m2 radar cross section
are reliably tracked at distances up to 100 km
over the sea and wood-covered terrain
Near 1-m range resolution provided identification
of targets and measurement of target parameters
(in particular, the rotation of a helicopter’s
blades)
Nanosecond radar system
(United Kingdom Ministry of Defense)

10. Millimeter-wave radars
The gain of an antenna: limited to G < ( D / )2
(D: the antenna diameter)
Tradeoffs in choosing the optimum operating frequency of a radar system:
directionality, resolution, Doppler sensitivity,
atmospheric attenuation, and the effective cross section
of the scattering objects
The potential advantages of millimeter-wave radars over lower
frequency systems:
smaller antennas, narrower beam widths,
greater Doppler sensitivity,
lower vulnerability to jamming or intercept,
reduced clutter and multipath effects,
and higher precision target location

11. Areas in which high-power millimeter-wave radars
are strongly advantageous
active monitoring of the atmosphere and search for debris in space
Monitoring of the atmosphere by millimeter-
wave radars makes it possible to study the dynamics of
clouds and to resolve multiple cloud layers
Increasing the average transmitter
power by three orders of magnitude, a 94-GHz radar system
could overcome an additional 30 dB of atmospheric absorp-
tion, which would increase the useful range by at least 15 km
in the most humid conditions
Advances in the millimeter-wave radars are related
to advances in millimeter-wave amplifier tubes, and in particular
to the development of gyroklystrons

12. 35-GHz gyroklystron producing 750 kW in 100-ms pulses
at 5 Hz repetition rate
94 GHz, GKL with 65 kW output power and 0.3% bandwidth
The progress in the development of high-power GKLs
has led to the suggestion to build a 35-GHz radar capable of
detecting small-size orbital debris that is dangerous for
spacecraft and space stations
Approximately 20 MW of power is required
to detect a 1-cm object at a range
of 1000 km using a 20-m tracking antenna
Four such stations, distributed along the Earth’s
equator, would be enough to catalog orbital debris larger
than 1 cm