Time-Domain Multimode Analysis of a Terahertz Gyro-TWT Amplifier

Du, Chao‐Hai; Shi, Peng; Bian, Hui-Qi; Liu, Pu‐Kun

doi:10.1109/ted.2018.2808178

Cited by 13 publications

(2 citation statements)

References 29 publications

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“…Of all the beam-wave interaction configurations, high loss DL circuit has been widely used to design the gyro-TWA because of its merits of strong attenuation ability to parasitic modes, which allows the gyro-TWA operating with a very high gain [13,14]. This feature makes it possible to apply in the terahertz band [15][16][17]. Based on the high loss DL circuit, at the University of Electronic Science and Technology of China (UESTC), a series of gyro-TWAs covering X, Ku, Ka, Q, and W bands has been successfully developed [5,14,[18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Theory, Simulation and Millimeterwave Measurement of the Operating and Parasitic Modes in a High Loss Dielectric Loaded Gyrotron Traveling Wave Amplifier (Invited)

Wang¹,

Jiang²,

Yao³

et al. 2021

PIER C

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In the gyrotron traveling wave amplifier (gyro-TWA), high loss dielectric materials loaded in a cylindrical waveguide are adopted to suppress the unwanted parasitic oscillations. It is of great importance to accurately understand the relative permittivity r and tan δ for studying the microwave and millimeter wave dispersion, and loss properties of a specific mode. The high lossy dielectric loaded circuits of the gyro-TWAs made of the BeO-SiC ceramic are theoretical calculated, simulated, and measured. The field distribution, dispersion, and loss properties of three different dielectric loaded circular HE d 12 , HE d 22 , and TE d 02 modes (corresponding to the TE 11 , TE 21 , and TE 01 modes in the smooth hollow cylindrical waveguide respectively) in different frequency bands are respectively investigated. The theoretical analysis, simulation, and measurement results have a good agreement. This work has clear guiding significance for the stable work of gyro-TWAs.

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Section: Introductionmentioning

confidence: 99%

Theory, Simulation and Millimeterwave Measurement of the Operating and Parasitic Modes in a High Loss Dielectric Loaded Gyrotron Traveling Wave Amplifier (Invited)

Wang¹,

Jiang²,

Yao³

et al. 2021

PIER C

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“…while Q is the total Q-factor, Qd and Qohm is diffraction Q-factor and ohmic Q-factor, respectively. Qd at different interaction lengths are calculated based on the single-mode [8] and are shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

Study of 1-THz 4th-Harmonic Gyrotron

Shi

et al. 2019

2019 12th UK-Europe-China Workshop on Millimeter Waves and Terahertz Technologies (UCMMT)

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A preliminary design of a 1-THz gyrotron based on the fourth harmonic operation is presented. The cylindrical-waveguide TE4,8 mode is selected as the operating mode. Considering the weak beam-wave coupling strength in a 4 th-harmonic open-cavity interaction circuit at the frequency of 1 THz, this paper proposes applying low-temperature cooling, for example applying liquid nitrogen, to increase the limit of the Q factor and extend the effective length of the cavity resulting in a significant enhancement of the interaction efficiency and suppression of ohmic losses. Applying multi-mode time-domain theory in the simulation, it was found that although the competing third-harmonic TE3,6 mode was excited first, the fourth-harmonic TE4,8 mode finally dominates in the steady state regime.

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Comparative analysis of terahertz fourth-harmonic gyro-TWAs and multiplying gyro-TWAs with axis-encircling electron beams

et al. 2020

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The harmonic operation in a terahertz gyrotron traveling-wave amplifier (gyro-TWA) permits a reduced magnetic field, whereas a harmonic multiplying gyro-TWA enables magnetic field reduction and frequency multiplication. This study comparatively analyzes the 400-GHz fourth-harmonic gyro-TWAs and fourth-harmonic multiplying gyro-TWAs with axis-encircling electron beams. This property of the gyro-TWAs with axis-encircling electron beams enables us avoid the appearance of the majority of the competing modes. According to the simulation results obtained using multi-mode codes, the attenuating severs suppress the remaining competing modes. In the case of a harmonic gyro-TWA containing a sever section, the copper-section start-oscillation length is significantly influenced by a decrease in the sever-section radius when compared with an increase in the sever-section length. Furthermore, a stable fourth-harmonic TE41-mode gyro-TWA containing sever sections is proposed. We propose fourth-harmonic TE41-mode multiplying gyro-TWAs, where the drive stages operate in the fundamental-harmonic TE11 mode to reduce the frequency of the drive wave. We subsequently develop a stable fourth-harmonic multiplying gyro-TWA with sever sections in the drive and amplified stages to avoid the competing modes and enhance the output power. The stable high-gain fourth-harmonic gyro-TWA can yield a peak output power of 2.7 kW at 400.6 GHz with a saturated gain of 75 dB and a bandwidth of 0.7 GHz for a 75-kV and 2-A electron beam with an axial velocity spread of 3%. Furthermore, a peak output power of 1.7 kW can be obtained by the fourth-harmonic multiplying gyro-TWA at 400.4 GHz with a saturated gain of 57 dB and a bandwidth of 0.4 GHz. Subsequently, we calculate the power and gain scaling for the harmonic gyro-TWA and harmonic multiplying gyro-TWA.

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Time-Domain Multimode Analysis of a Terahertz Gyro-TWT Amplifier

Cited by 13 publications

References 29 publications

Theory, Simulation and Millimeterwave Measurement of the Operating and Parasitic Modes in a High Loss Dielectric Loaded Gyrotron Traveling Wave Amplifier (Invited)

Theory, Simulation and Millimeterwave Measurement of the Operating and Parasitic Modes in a High Loss Dielectric Loaded Gyrotron Traveling Wave Amplifier (Invited)

Study of 1-THz 4th-Harmonic Gyrotron

Comparative analysis of terahertz fourth-harmonic gyro-TWAs and multiplying gyro-TWAs with axis-encircling electron beams

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