Journal ArticleDOI
The Propagation Constants of Higher-Order Modes in Coaxial Waveguides With Finite Conductivity
Chien-Lun Hung,Yi Sheng Yeh +1 more
TLDR
In this paper, the authors employed the perturbational method to determine the propagation constants of higher-order modes in the coaxial waveguide, and the validity of the theoretical model is confirmed by comparison with results obtained using the high-frequency structure simulator.Abstract:
Overmoded coaxial waveguides have been used in coaxial gyrotrons as a key interaction structure. To achieve the required mode selectivity, the resistivity of the center conductor is properly chosen to damp unwanted modes. Considering attenuation due to conductor loss, this study employs the perturbational method to determine the propagation constants of higher-order modes in the coaxial waveguide. The validity of the theoretical model is confirmed by comparison with results obtained using the high-frequency structure simulator (HFSS). Moreover, the method proposed herein is applied to analyze the ohmic mode selection of the coaxial waveguide.read more
Citations
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Journal ArticleDOI
Stability analysis of a coaxial-waveguide gyrotron traveling-wave amplifier
C. L. Hung,Y. S. Yeh +1 more
TL;DR: In this paper, the authors developed a simulation approach to analyze the stability of a coaxial-waveguide gyro-TWT with distributed wall losses, and the interplay among the absolute instabilities, the gyrotron backward-wave oscillations, and circuit parameters was analyzed.
Journal ArticleDOI
Linear analysis of a coaxial-waveguide gyrotron traveling-wave tube
TL;DR: In this article, the authors presented a linear theory which is applicable to amplifications or self-excited oscillations induced by absolute instabilities in a coaxial waveguide of finite length.
Journal ArticleDOI
Selective Suppression of Electromagnetic Modes in a Rectangular Waveguide by Using Distributed Wall Losses
TL;DR: In this article, a method of selective suppression of electromagnetic modes in rectangular waveguides by loading distributed losses in some special position of waveguide inner wall is presented, which can be used to improve the stability of rectangular waveguide beam-wave interaction circuit.
Journal ArticleDOI
Geometrical Effects on the Performance of Coaxial-Waveguide Gyrotron Traveling-Wave Amplifiers
TL;DR: In this article, the feasibility of improving the stability of the coaxial-waveguide gyrotron traveling-wave tube (gyro-TWT) by selecting the geometrical parameter C, i.e., the ratio of the outer radius to the inner radius, was examined.
Journal ArticleDOI
Low-voltage harmonic multiplying gyrotron traveling-wave amplifier in G band
TL;DR: In this paper, an improved mode-selective circuit, using circular waveguides with various radii, can provide the rejection points within the frequency range to suppress competing modes.
References
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Journal ArticleDOI
Operation of a stable 200-kW second-harmonic gyro-TWT amplifier
TL;DR: In this article, a stable second-harmonic gyrotron traveling wave amplifier, which generated a record-breaking 207kW output power based on the principle that the weaker harmonic interactions are more stable to spontaneous oscillations than at the fundamental, and therefore, capable of generating higher output power.
Journal ArticleDOI
Coaxial cavity gyrotron- recent experimental results
TL;DR: The feasibility of fabrication of coaxial cavity gyrotrons with an output power up to 2 MW, continuous wave (CW) has been demonstrated and information necessary for a technical design has been obtained.
Journal ArticleDOI
Theory of gyrotrons with coaxial resonators
TL;DR: In this paper, the selective properties of various coaxial resonators as well as ohmic losses of the microwave power in outer and inner conductors are considered and the start-up scenario in powerful gyrotrons is discussed.
Journal ArticleDOI
Geometrical effects in gyrotron coaxial cavities: application to mode selection
TL;DR: In this paper, a study of the electrodynamical properties of gyrotron coaxial cavities using a conical inner rod has been conducted and compared with cold-test measurements on TE modes over the frequency range 11-14 GHz.
Journal ArticleDOI
Spectral Domain Analysis of Coaxial Cavities
Chien Lun Hung,Yi Sheng Yeh +1 more
TL;DR: In this paper, the authors apply the incident/reflected wave boundary condition to the wave equation of a weakly irregular coaxial waveguide, and the resistivity of the wall is considered in the analysis.