A 140-GHz Two-Beam Overmoded Folded-Waveguide Traveling-Wave Tube

Gong, Yubin; Yin, Hairong; Yue, Lingna; Lu, Zhaolin; Wei, Yanyu; Feng, Jinjun; Duan, Zhaoyun; Xu, Xiong

doi:10.1109/tps.2010.2100410

Cited by 65 publications

(24 citation statements)

References 15 publications

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“…Same approach applies also to our system with a significant difference: in the case when the DBE condition is satisfied, all four degenerate EM modes rather than one interact synchronously with the induced charge wave. In similar manner, we distinguish our approach from overmoded SWS designs 34,35 thanks to the degeneracy condition.…”

Section: Ctl Model Of a Periodic Waveguide With A Dbe Interactingmentioning

confidence: 99%

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

et al. 2016

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We propose a new amplification regime based on synchronous operation of four degenerate electromagnetic (EM) modes in a slow-wave structure and the electron beam, referred to as super synchronization. These four EM modes arise in a Fabry-Pérot cavity (FPC) when degenerate band edge (DBE) condition is satisfied. The modes interact constructively with the electron beam resulting in superior amplification. In particular, much larger gains are achieved for smaller beam currents compared to conventional structures based on synchronization with only a single EM mode. We demonstrate giant gain scaling with respect to the length of the slow-wave structure compared to conventional Pierce type single mode traveling wave tube amplifiers. We construct a coupled transmission line (CTL) model for a loaded waveguide slow-wave structure exhibiting a DBE, and investigate the phenomenon of giant gain via super synchronization using the Pierce model generalized to multimode interaction.

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Section: Ctl Model Of a Periodic Waveguide With A Dbe Interactingmentioning

confidence: 99%

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

et al. 2016

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“…Over-moded W-band TWTs have been proposed which would allow the possibility of larger beam tunnels and the need for less magnetic field overall [9], [8], [21]. An over-moded design, meaning a design which operates in a cavity mode which is at a higher frequency than the fundamental cavity mode, is oversized for its intended frequency of operation.…”

Section: An Over-moded Twt Designmentioning

confidence: 99%

Overmoded W-Band Traveling Wave Tube Amplifier

Temkin¹,

Kowalski²

2014

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Air Force Materiel Command REPORT DOCUMENTATION PAGEForm Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information We report on the design and test of an overmoded W-band TWT. The TWT was designed to operate in the rectangular TM31 cavity mode at 94 GHz. The unwanted lower order modes were suppressed using selectively placed AlN dielectric loading; simulations in 3-D CST Particle Studio confirmed the suppression. The 87-cavity TWT was designed to operate at 30 kV with 320 mA in a 2.5 kG solenoid magnet. The experiment was built in-house at MIT and operated with a 3 microsecond pulsed power supply. An initial beam test was implemented which confirmed operation at 31 kV with 306±6 mA of current detected at the collector and 88 % transmission. The TWT produced 21±2 dB system gain at 94.3 GHz and 27 W of saturated output power in zero-drive stable operation. The TWT had about 6 dB of additional loss due to the input and output coupling; taking that loss into account, the gain on the TWT circuit itself was 27±2 dB circuit gain. CST simulations for the experimental current and voltage predict 28 dB circuit gain, in good agreement with measurements. This experiment demonstrated the first successful operation of an overmoded TWT. The overmoded TWT is a promising approach to high power TWT operation at W-Band and to the extension of the TWT to terahertz frequencies. AbstractWe report on the design and test of an overmoded W-band TWT. The TWT was designed to operate in the rectangular TM31 cavity mode at 94 GHz. The unwanted lower order modes, TM11 and TM21, were suppressed using selectively placed Aluminum Nitride dielectric loading; simulations in 3-D CST Particle Studio confirmed the suppression. The TWT was designed to operate at 30 kV with 320 mA in a 2.5 kG solenoid magnet. Simulations in both 1-D Latte and 3-D CST predicted 31 dB of gain, 200 MHz bandwidth, and 300 W peak output power at 94 GHz. Test structures of 9-and 19-cavities were made via CNC direct machining. Cold test measurements showed suppression of the unwanted modes and transmission of the TM31 mode, which correlated well with HFSS simulations. Two final 87-cavity structures were built and cold tested.The experiment was designed and built in-house at MIT. It was operated with a 3 microsecond pulsed power supply. An initial beam test was implemented which confirmed operation of the TWT at 31 kV with 306±6 mA of current detected at the collector and 88 % transmission of current. Operation of the TWT with the first structure showed 8 dB of system gain and 10 W saturated output power at 95.5 GHz....

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“…While operating outside the band, the performance of the device may dramatically decrease due to the deterioration of the transmission property. All the calculations are under the assumption that the circuit material is oxygen-free highconductivity (OFHC) copper with the roughness of circuit wall and fabrication error considered, thus the conductivity is 2.20 10 7 S/m [10]. …”

Section: Model Of Backward Wave Oscillatormentioning

confidence: 99%

A 140 GHz staggered double vane backward wave oscillator

Lai

Wei

et al. 2012

Proceedings of 2012 5th Global Symposium on Millimeter-Waves

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AbstractíStaggered double vane structure was used as the slow wave circuit and sheet beam was applied to design a 140GHz backward wave oscillator. A transition structure for the circuit was proposed to minimize the attenuation and reflection of the system. Numerical calculation results demonstrated that the oscillator can produce the average output power in excess of 1 watt ranging from 134-146GHz with the beam current of 10mA and accelerating voltage around 20kV. Such design offers the microwave community a promising solution for short-millimeter wave radiation source.

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A 140-GHz Two-Beam Overmoded Folded-Waveguide Traveling-Wave Tube

Cited by 65 publications

References 15 publications

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

Giant amplification in degenerate band edge slow-wave structures interacting with an electron beam

Overmoded W-Band Traveling Wave Tube Amplifier

A 140 GHz staggered double vane backward wave oscillator

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