Start current study of a THz sheet beam extended interaction oscillator

Xu, Che; Wang, Bin; Peng, Ruibin; Bi, Liangjie; Zeng, Fanbo; Chang, Zhiwei; Zhu, Sairong; Yin, Yong; Li, Hailong; Meng, Lin

doi:10.1063/1.5027445

Cited by 16 publications

(4 citation statements)

References 14 publications

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“…The operating mode field characteristics of the fourcoupling-hole disk-loaded structure are studied using commercially available 3D electromagnetic finite element analysis software (CST Microwave Studio). 36,37 Figures 3(a) and 3(b) show the dispersion characteristics of the two structures, respectively. The axial mode is planned as the 2π mode that provides an electric field in the same direction on each gap, which ensures that the effective modulation of the electron beam.…”

Section: Circuit Characteristics and Stability Analysismentioning

confidence: 99%

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Study of an overmoded structure for megawatt Ka-band extended interaction klystron

Zu,

Yuan,

et al. 2023

Physics of Plasmas

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For most applications in the millimeter wave band, corresponding to Ka and higher-frequency bands, relatively high atmospheric absorption necessitates the use of high-power sources. Here, a new approach for projecting an oversized beam tunnel in an overmoded structure by concentrating the axial field is demonstrated to meet the high-frequency and high-power demands of compact devices. Due to the enhanced intense beam loading capability of the interaction circuit, a six-cavity Ka-band extended interaction klystron with a four-coupling-hole disk-loaded structure is designed that can stably obtain high output power. An analysis of optimization tradeoffs from introducing high order modes for allowing the application of more powerful beams to improving high order mode field distribution for enhancing the electron-wave coupling and suppressing mode competition is reported. 3D particle-in-cell simulations show attainable output powers of 1.11 MW at 32.94 GHz with a saturated gain of 57 dB by injecting a 3.3 mm diameter electron beam with a current of 24 A.

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Section: Circuit Characteristics and Stability Analysismentioning

confidence: 99%

“…Coupling coefficient M and characteristic impedance R/Q of the resonant circuit are important and commonly used indices that capture the energy coupling between the high-frequency field and electron beam. R/Q and M can be assessed from 37 ( )…”

Section: Circuit Characteristics and Stability Analysismentioning

confidence: 99%

Study of an overmoded structure for megawatt Ka-band extended interaction klystron

Zu,

Yuan,

et al. 2023

Physics of Plasmas

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“…Operating at an ion density around 10 17 m -3 is preferred as the balance point between beam current and the beam quality. If an interaction circuit operating at TM01 mode with a beam tunnel radius of 0.29 mm, corresponding to a cut-off frequency of 400 GHz, the maximum beam current is ~0.1 A, with which it is difficult to satisfy the starting current condition taking into consideration the high ohmic loss at high frequency [28].…”

Section: Ps-sourced Beam Transportation In a Small Beam Tunnelmentioning

confidence: 99%

Simulations of the Self-Focused Pseudospark-Sourced Electron Beam in a Background Ion Channel

Zhang¹,

Phelps

Ronald

et al. 2021

IEEE Access

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Using pseudospark discharge sourced electron beams for the generation of high-peak-power millimeter and terahertz radiation attracts increasing research interest in recent years. However, one of the crucially important and hitherto unanswered questions is "what is the upper-frequency limit at which millimeter-wave devices can be driven by pseudospark discharge sourced electron beams?". In this paper, we studied this question from the perspective of beam transportation in a plasma background, more specifically an ion channel using particle-in-cell simulations to find the limitations. The parameter ranges of the beam transportation with small oscillations in the beam diameter were investigated and summarized, through simulations of beam propagation in a large diameter drift tube with different ion densities, plasma electron densities, beam density distributions, and beam energies. The beam transportation in a small diameter beam tunnel was also simulated. It showed the maximum beam current with a small velocity spread that can be transported in the beam tunnel was determined by the diameter of the beam tunnel and the ion density. High injected current will cause significant beam loss and reduce the overall efficiency. The simulation results indicate a minimum diameter of the beam tunnel in a millimeter-wave circuit that can be effectively driven by a pseudospark-sourced electron beam. The equivalent upper limit in the operating frequency is about 400 GHz.

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“…As a result, mode competition can be suppressed. Additionally, compared with traditional cylindrical electron beams, the broader transverse proportion in the sheet beam, developed here, provides a high current and increases the output power of the device substantially (>30%) [16].…”

Section: Introductionmentioning

confidence: 99%

Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode

Yuan

et al. 2019

Nanomaterials

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Carbon nanotube (CNT) cold cathodes are proving to be compelling candidates for miniaturized terahertz (THz) vacuum electronic devices (VEDs) owning to their superior field-emission (FE) characteristics. Here, we report on the development of a multi-sheet beam CNT cold cathode electron optical system with concurrently high beam current and high current density. The microscopic FE characteristics of the CNT film emitter is captured through the development of an empirically derived macroscopic simulation model which is used to provide representative emission performance. Through parametrically optimized macroscale simulations, a five-sheet-beam triode electron gun has been designed, and has been shown to emit up to 95 mA at 3.2 kV. Through careful engineering of the electron gun geometric parameters, a low-voltage compact THz radiation source operating in high-order TM 5 , 1 mode is investigated to improve output power and suppress mode competition. Particle in cell (PIC) simulations show the average output power is 33 W at 0.1 THz, and the beam–wave interaction efficiency is approximately 10%.

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Start current study of a THz sheet beam extended interaction oscillator

Cited by 16 publications

References 14 publications

Study of an overmoded structure for megawatt Ka-band extended interaction klystron

Study of an overmoded structure for megawatt Ka-band extended interaction klystron

Simulations of the Self-Focused Pseudospark-Sourced Electron Beam in a Background Ion Channel

Design and Simulation of a Multi-Sheet Beam Terahertz Radiation Source Based on Carbon-Nanotube Cold Cathode

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