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A gyrotron operating at the second cyclotron harmonic in a magnetic field of 9.7 T has produced a CW output power of 25 W at 527 GHz. The gyrotron is now being employed in Dynamic Nuclear Polarization (DNP) Applications. The gyrotron design and results of the tests are presented.
We find that the surface resistance of copper exceeds that predicted by classical electromagnetic theory. The small but significant discrepancy we find is consistent with results reported in adjacent frequency ranges. We will also present measurements of the reflectivity of rough copper surfaces and compare these results to theoretical predictions.
Micro-reentrant square cavities operating at high order modes have been demonstrated to be a viable solution for the realization of millimeter wave klystrons. However, the excitation of the required high order mode is a challenging task. The realization and measurement of a novel coupler for high order mode cavities is proposed.
A 220 GHz power amplifier has been demonstrated as part of the DARPA HiFIVE program. This amplifier is based on a folded waveguide circuit, and operates at 19 kV and 250 mA. Short pulse tests resulted in 56 W at 214 GHz and a 5.0 GHz bandwidth.
A slotted single-grating rectangular waveguide is proposed as the SWS of a novel 0.65 THz BWO. Utilizing HFSS, the cold electromagnetic performance of the SWS is studied. Input/output structure is designed. This BWO is verified by a 3-D particle-in-cell simulation using MAFIA. A 0.88W peak output power at 0.65THz is obtained under 12-kV operating voltage and 7-mA beam current.
This paper presents theory and analysis of single-tip field emission and electron beam propagation in the electrostatic focusing fields. It is shown that two gate apertures with a focusing anode allow transport of narrow electron beams over long distances without need for a confining magnetic field. Physical mechanisms of the beam formation, transport, intrinsic emittance with thermal effects, the...
A 0.850 THz vacuum electronic power amplifier capable of >50 mW output power is being tested at Northrop Grumman Electronic Systems. The compact power amplifier is based on a DRIE-fabricated folded waveguide slow-wave circuit, together with a high current density thermionic cathode, a high field permanent magnet solenoid, and a single-stage depressed collector for overall device efficiency. The...
A new way to control the electron beam current is proposed based on nonrelativistic electron beam and millimeter wave interaction. Simulation shows specific high harmonic current was generated while other harmonic components were suppressed. This current can be used to generate terahertz wave by a new beam wave interaction process.
Northrop Grumman Electronic Systems is developing vacuum-based power amplifiers operating at G-band with over 50W of output power and 3.5 GHz bandwidth. New power module configurations using a single electron beam, compact solenoidal magnet, and integrated power conditioner are being developed for system integration on airborne platforms.
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