Stable high-power TE/sub 01/ gyro-TWT amplifiers

Leou, Keh-Chyang; McDermott, D.B.; Balkcum, Adam; Luhmann, Neville C.

doi:10.1109/27.338271

Cited by 40 publications

(15 citation statements)

References 22 publications

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“…It is clear that two types of spurious oscillations may be excited: oscillations coming from the absolute instability at the cutoff frequency of the TE11 mode and gyrotron backward-wave oscillation (gyro-BWO) at the beam-wave cross point of the TE21 mode. The beam current must be maintained below the threshold current (Ist) to ensure stability; also, the interaction length must be kept shorter than a critical length (Lc) beyond which gyrotron backward wave oscillations will occur [9].…”

Section: Stability Analysismentioning

confidence: 99%

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Liu

2010

J Infrared Milli Terahz Waves

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A Ka-band gyrotron traveling wave (gyro-TWT) amplifier with high power and wide bandwidth operated in the fundamental TE11 circular mode is presented in detail. The stability of the gyro-TWT amplifier using linear and nonlinear theory is analyzed. The distributed loss technique is employed in the interaction circuit which guarantees the amplifier zero-drive stability. The effects of the parameters such as input power, driver frequency, magnetic field on the performance of the gyro-TWT is discussed. The simulation results show that the gain and the bandwidth of the designed Ka-band gyro-TWT are about 60.0 dB and 1.4 GHz at constant drive with an axial velocity spread $v z =v z ¼ 5%. The peak output power and the corresponding electronic efficiency are about 111 kW and 26.4% respectively for a 70 kV, 6A electron beam at 35 GHz. In addition, the design of the input coupler, a triode-type magnetron injection gun (MIG) and a triple output window are given.

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Section: Stability Analysismentioning

confidence: 99%

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Liu

2010

J Infrared Milli Terahz Waves

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“…To evaluate the performance of a stable gyro-TWT amplifier, some nonlinear self-consistent simulation codes based on a set of slow-time scale formulation have been developed [12,13]. Large-signal operation of the gyro-TWT can be described by the equations for the changes in electron energy and phase and in the wave amplitude along the axis.…”

Section: General Equationsmentioning

confidence: 99%

Design and Simulation of an Ultra-Broadband Ku-BandGyro-TWT for Radar Applications

Geng

Liu

et al. 2008

Int J Infrared Milli Waves

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In this paper, the design of an ultra-broadband Ku-band gyro-TWT amplifier is presented in detail. The preliminary parameters of the interaction structure derived from the dispersion relationship and the linear theory of the gyro-TWT with distributed wall losses is optimized by the self-consistent nonlinear code. The performance of the designed gyro-TWT is simulated by the nonlinear code. The simulation results show that the gain and the bandwidth of the designed Ku-band gyro-TWT is about 36.5 dB and 2.1 GHz with 3 dB bandwidth (about 12.7%) respectively at the input power 19.0 W.

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“…The TE 01 mode used in gyro-TWTs exhibits lower ohmic dissipation and a larger guiding centre) radius (Leou et al 1994, Hirata et al 2000. Therefore, a magnetron injection gun (MIG) to generate a high-quality electron beam can be easily constructed (Leou et al 1994, Yeh et al 2000, 2001.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, a magnetron injection gun (MIG) to generate a high-quality electron beam can be easily constructed (Leou et al 1994, Yeh et al 2000, 2001. In an early, experimental TE 01 gyro-TWT at the US Naval Research Laboratory (NRL), absolute instability caused an oscillation near cutoff (Seftor et al 1979, Barnett et al 1980.…”

Section: Introductionmentioning

confidence: 99%

Stability analysis of TE₀₁gyrotron travelling wave amplifiers

Yeh

et al. 2003

International Journal of Electronics

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The fundamental harmonic TE 01 gyrotron travelling wave amplifier (gyro-TWT) is a high-power, broadband, millimetre-wave amplifier with a low ohmic dissipation and a large guiding centre radius. However, spurious oscillations may reduce the amplification of the gyro-TWT. The stability of severed and distributed-loss gyroTWTs is analysed, using a self-consistent simulation code. A nonlinear analysis of typical oscillations, including absolute instability, gyrotron backward oscillation (gyro-BWO) and reflective oscillation, is presented. Simulation results indicate that attenuating severs in the severed gyro-TWT do not suppress spurious oscillations, and that increasing the wall losses to suppress gyro-BWO in the distributed-loss gyro-TWT degrades the efficiency of the gyro-TWT amplifier. A multi-stage distributed-loss gyro-TWT design is developed to stabilize the amplification. The lossy and severed sections of the multi-stage gyro-TWT seem to increase effectively the start-oscillation currents of absolute instability and gyro-BWO, respectively. The multi-stage gyro-TWT is predicted to yield a peak output power of 155 kW at 32.9 GHz with an efficiency of 15%, a saturated gain of 45 dB and a bandwidth of 2.2 GHz for a 100 kV, 10 A electron beam with an axial velocity spread Áv z /v z ¼ 5%.

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Stable high-power TE/sub 01/ gyro-TWT amplifiers

Cited by 40 publications

References 22 publications

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Design and Simulation of an Ultra-Broadband Ku-BandGyro-TWT for Radar Applications

Stability analysis of TE₀₁gyrotron travelling wave amplifiers

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Stable high-power TE/sub 01/ gyro-TWT amplifiers

Cited by 40 publications

References 22 publications

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Study of a Ka-Band TE11 Mode Gyrotron Traveling-Wave Amplifier

Design and Simulation of an Ultra-Broadband Ku-BandGyro-TWT for Radar Applications

Stability analysis of TE01gyrotron travelling wave amplifiers

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Stability analysis of TE₀₁gyrotron travelling wave amplifiers