High-power harmonic gyro-TWT's. I. Linear theory and oscillation study

Kou, C. S.; Wang, Q.S.; McDermott, D.B.; Lin, A. T.; Chin, Kwan-Wu; Luhmann, Neville C.

doi:10.1109/27.142815

Cited by 93 publications

(24 citation statements)

References 26 publications

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“…The input coupler reflected power was measured to be < -5 dB in the operating mode with < -25 dB coupling to the TEn and TE 2 i modes across this band. The total length of the unloaded input coupler was 1.5 cm, which was well below the critical length for start oscillation for all modes as calculated from linear theory [19]. The inner radius of the cylindrical input coupler was the same as the circuit radius (0.5495 cm), hence the TEoi mode propagated on to the gyro-TWT interaction region with no step or taper.…”

Section: A Teoi Gyro-twt Circuit Designmentioning

confidence: 82%

“…This code was previously used to design and model gyroklystron amplifiers [21] and was also used to design a TEn gyro-TWT [3]. The lengths of the loaded and unloaded sections were chosen to satisfy stability constraints as well as overall amplifier gain, bandwidth, and efficiency performance based on linear theory calculations [19] and MAGY simulations. The critical oscillation lengths of any spurious modes for an unloaded waveguide of radius 0.5495 cm were calculated and the limiting length was determined to be 4.55 cm for the TE02 second harmonic mode.…”

Section: A Teoi Gyro-twt Circuit Designmentioning

confidence: 99%

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A gyrotron-traveling-wave tube amplifier experiment with a ceramic loaded interaction region

Garven

Calame

Danly

et al. 2002

IEEE Trans. Plasma Sci.

171

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Abstract-The design and experimental study of a 35-GHz gyrotron-traveling-wave tube (gyro-TWT) amplifier operating in the circular TE 0 i mode at the fundamental cyclotron harmonic are presented. The interaction circuit in this experiment consisted of a new type of ceramic loading that provided the required loss for stable operation. A saturated peak power of 137 kW was measured at 34.1 GHz, corresponding to a saturated gain of 47.0 dB and an efficiency of 17%, with a -3-dB bandwidth of 1.11 GHz (3.3%). Peak output powers in the range of 102.1 to 148.6 kW with -3-dB bandwidths of 1.26 and 0.94 GHz, respectively, were measured by varying the operating parameters. The gyro-TWT was found to be zero-drive stable at these operating points, demonstrating that ceramic loading is a highly effective means of suppressing spurious oscillations in gyro-TWTs. This type of ceramic loading has the added advantage of being compatible with high average power operation.

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Section: A Teoi Gyro-twt Circuit Designmentioning

confidence: 82%

Section: A Teoi Gyro-twt Circuit Designmentioning

confidence: 99%

A gyrotron-traveling-wave tube amplifier experiment with a ceramic loaded interaction region

Garven

Calame

Danly

et al. 2002

IEEE Trans. Plasma Sci.

171

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show abstract

“…So, it is important to study these effects too in order to make sure that the required mode alone dominates the mode competition. A poor coupling of the volume modes near the wall as well as a larger frequency separation between competing modes reduces the competition in a high beam harmonic operation of the device in the whispering gallery mode, the high-harmonic operation reducing the background magnetic field requirement [47,49,50].…”

Section: Problem Formulationmentioning

confidence: 99%

Analytical Study of the Interaction Structure of Vane-Loaded Gyro-Traveling Wave Tube Amplifier

Singh¹

2008

PIER B

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Abstract-This article discusses the-state-of-the-art of the vaneloaded gyrotron traveling wave tube (gyro-TWT) amplifier, which is device of increasing importance for high resolution radar and high information density communication systems because of its high-power and broad bandwidth capabilities. Vane loading is identified as a means to achieve a low-beam energy, high-harmonic, low-magnetic field, mode-selective and stable operation of a gyro-TWT. Thus, the development of a simple approach to the analysis of the interaction structure of vane-loaded gyro-TWT has been identified as a problem of practical relevance.

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“…One way to increase I s is to apply loss to the gyro-TWT circuit. Calculation results of I s employing linear theory [2][3][4] and nonlinear theory [5] were reported for lossy gyro-TWT. However, using these methods require in-depth analysis on linear and nonlinear theories of gyro-TWT.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Start-Oscillation-Current for Lossy Gyrotron Traveling-Wave Tube (Gyro-TWT) Using Linear Traveling-Wave Tube (TWT) Parameter Conversions

Song¹

2013

JEMAA

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The start-oscillation-current of a gyro-TWT (gyrotron traveling-wave tube) determines the stable operating current level of the device. The amplifier is susceptible to oscillations when the operating current level is higher than the start-oscillation current. There are several ways of calculating the start-oscillation current, including using the linear and nonlinear theory of a gyro-TWT. In this paper, a simple way of determining the start-oscillation current of lossy gyro-TWT is introduced. The linear TWT parameters that include the effects of synchronism, loss, and gain, were converted to gyro-TWT parameters to calculate the start-oscillation-current. The dependence on magnetic field, loss, and beam alpha was investigated. Calculations were carried out for a V-band gyro-TWT for both operating and competing modes. The proposed method of calculating the start-oscillation current provides a simple and fast way to estimate the oscillation conditions and can be used for the design process of a gyro-TWT.

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High-power harmonic gyro-TWT's. I. Linear theory and oscillation study

Cited by 93 publications

References 26 publications

A gyrotron-traveling-wave tube amplifier experiment with a ceramic loaded interaction region

A gyrotron-traveling-wave tube amplifier experiment with a ceramic loaded interaction region

Analytical Study of the Interaction Structure of Vane-Loaded Gyro-Traveling Wave Tube Amplifier

Calculation of Start-Oscillation-Current for Lossy Gyrotron Traveling-Wave Tube (Gyro-TWT) Using Linear Traveling-Wave Tube (TWT) Parameter Conversions

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