Experimental investigation of a broadband dielectric-loaded gyro-TWT amplifier

Leou, Keh-Chyang; McDermott, D.B.; Chong, C.K.; Luhmann, Neville C.

doi:10.1109/16.502138

Cited by 23 publications

(12 citation statements)

References 21 publications

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“…2 A dielectric-loaded gyro-TWT, also at UCD, yielded a peak power of 55 kW with an efficiency of 11%, a saturated gain of 27 dB, a constant-drive bandwidth of 11% and a saturated bandwidth of over 14% in the X band. 3 At the National Tsing Hua University, Taiwan, an ultrahigh-gain gyro-TWT experiment achieved a saturated peak power of 93 kW at a 70 dB gain and 26.5% efficiency with a 3 dB bandwidth of 8.6% in the Ka band. 4,5 A group from Russia and the United Kingdom has developed a gyro-TWT with a helically corrugated interaction structure.…”

Section: Introductionmentioning

confidence: 99%

“…10 To date, most gyro-TWTs have used either cylindrical or rectangular waveguides as interaction structures. [1][2][3][4][5][8][9][10] The high power capability of the gyro-TWTs has been limited by spurious oscillations, which compete with the operating mode and prevent the gyro-TWTs from operating in the optimum parameter regime. Recently, problems of mode competition in a high-power gyrotron oscillator have been reduced using coaxial structures, [11][12][13][14][15] so several studies have examined the possibility of using a coaxial waveguide as the interaction structure of a gyro-TWT.…”

Section: Introductionmentioning

confidence: 99%

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Linear analysis of a coaxial-waveguide gyrotron traveling-wave tube

Hung

2006

Physics of Plasmas

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Linear theory provides an efficient analysis model for the preliminary design of a gyrotron traveling-wave tube (gyro-TWT). This study presents a linear theory, which is applicable to amplifications or self-excited oscillations induced by absolute instabilities in a coaxial waveguide of finite length. The effects of wall losses are incorporated in the theoretical formalism. The validity of the linear theory is verified by comparison with calculation results obtained using an existing self-consistent nonlinear theory. The linear theory is applied to analyze a TE01 mode coaxial gyro-TWT at the fundamental cyclotron harmonic. Numerical analysis of coupling between the beam cyclotron mode and the waveguide mode provides physical insight into the wave-growing mechanisms of various oscillations. The critical parameters for the onset of threatening oscillation modes are analyzed to determine the stable operating conditions. Finally, the dependencies of small-signal amplifications on system parameters are studied in great detail.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Linear analysis of a coaxial-waveguide gyrotron traveling-wave tube

Hung

2006

Physics of Plasmas

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“…It also exhibits important potential in gyro-TWT applications, and a series of theoretical and experimental researches have been carried out. [15][16][17][18][19] In 1982, a C-band slow-wave gyro-TWT experiment based on dielectric waveguide was reported. It achieved a tuning bandwidth of over 11%.…”

Section: Introductionmentioning

confidence: 99%

“…[1][2][3][5][6][7][8][11][12][13][14] The dielectric-loaded waveguide has been widely applied in gyrotron devices. [15][16][17][18][19] It is normally adopted as a drifting tube in a gyrotron or a gyroklystron, and functions as an important component to absorb the spurious oscillation power and strengthens the system stability. It also exhibits important potential in gyro-TWT applications, and a series of theoretical and experimental researches have been carried out.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear full-wave-interaction analysis of a gyrotron-traveling-wave-tube amplifier based on a lossy dielectric-lined circuit

Liu

2010

Physics of Plasmas

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The stability of the millimeter-wave gyrotron-traveling-wave-tube (gyro-TWT) amplifier can be effectively improved via controlling the propagation characteristics of the operating modes using lossy dielectric-lined (DL) waveguide. Self-consistent nonlinear theory of the electron cyclotron maser (ECM) interaction in lossy DL circuit is developed based on a full-wave study of the propagation characteristics of the DL waveguide. This nonlinear theory fully takes into consideration the waveguide structure and the lossy dielectric characteristics. It is capable of accurately calculating the ECM instability between a cyclotron harmonic and a circular polarized mode, and effectively predicting the nonlinear stability of the DL waveguide-based gyro-TWT. Systematic investigation of a Ka-band TE01 mode DL waveguide-based gyro-TWT is carried out, and numerical calculation reveals a series of interesting results. This work provides a basic theoretical tool for further exploring the application of the lossy DL waveguide in millimeter-wave gyro-TWTs.

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“…Third [11] and even sixth [12] harmonic gyro-TWTs have been investigated. Also at the University of California, a gyro-TWT partially loaded with dielectric produced 55 kW peak output power, 27 dB saturated gain, and a -3 dB bandwidth of 11% in the X-band frequency range [13]. Recently, at the National Tsing Hua University (NTHU), Taiwan, an ultrahigh gain gyro-TWT amplifier produced 93 kW peak power, with 70 dB saturated gain, 26.5% efficiency, !…”

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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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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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Experimental investigation of a broadband dielectric-loaded gyro-TWT amplifier

Cited by 23 publications

References 21 publications

Linear analysis of a coaxial-waveguide gyrotron traveling-wave tube

Linear analysis of a coaxial-waveguide gyrotron traveling-wave tube

Nonlinear full-wave-interaction analysis of a gyrotron-traveling-wave-tube amplifier based on a lossy dielectric-lined circuit

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

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