Analogy Between Circular Core-Cladding and Impedance Waveguides and Their Membrane Functions

Shcherbinin, Vitalii I.; Zaginaylov, G.I.; Ткаченко, В. І.

doi:10.2528/pierm16110902

Cited by 16 publications

(11 citation statements)

References 46 publications

(59 reference statements)

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“…Assume that the waveguide eigenfrequencies are close to cutoff frequencies. In this case, a dielectric-loaded waveguide is characterized by weaklycoupled TE and TM eigenmodes [32][33][34].…”

Section: Vacuum and Dielectric Modesmentioning

confidence: 99%

Mode Discrimination by Lossy Dielectric Rods in Cavities of Second-Harmonic Gyrotrons

Shcherbinin

Avramidis

Thumm

et al. 2021

J Infrared Milli Terahz Waves

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The influence of a coaxial dielectric rod on eigenvalues, ohmic losses, transverse field structure and beam-wave coupling coefficients is investigated for TE modes of a gyrotron cavity. It is shown that such dielectric insert, when made from a moderate-loss material, results in strong attenuation of all cavity modes, with the exception of those having caustic radii much larger than the insert radius. It is proposed to employ such dielectric loading for selective suppression of competing modes in cavities of second-harmonic gyrotrons. The high performance and flexibility of the proposed method of mode discrimination is demonstrated for the example of the cavity of the high-power 0.39-GHz second-harmonic gyrotron developed at the University of Fukui. In addition, some fascinating capabilities enabled by coaxial inserts made of ultralow-loss dielectrics are discussed.

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Section: Vacuum and Dielectric Modesmentioning

confidence: 99%

Mode Discrimination by Lossy Dielectric Rods in Cavities of Second-Harmonic Gyrotrons

Shcherbinin

Avramidis

Thumm

et al. 2021

J Infrared Milli Terahz Waves

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“…The same, we write it as HE d nm or EH d nm modes. It is worth mentioning that [27,28] (a proposed a simple way to distinguish the hybrid waves by using two membrane functions. In some cases, the TE 11 , TE 21 , and TE 01 modes in the smooth hollow waveguide are similar to the HE d 12 , HE d 22 , and TE d 02 modes in the dielectric loaded waveguide as shown in Fig.…”

Section: Theory Of the Dielectric Loaded Waveguidementioning

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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“…In the vicinity of the cutoff frequencies, the cavity modes of interest are (quasi-) TE modes [25]. Their eigenvalues and beam-wave coupling coefficients can be found from rigorous consideration [26], [27]. At the same time, for a small dielectric thickness d , when the field inside a dielectric layer has a small contribution to the power flow along the cavity, an approximation can be used.…”

Section: Coaxial Cavity With Dielectric-coated Insertmentioning

confidence: 99%

Improved Mode Selection in Coaxial Cavities for Subterahertz Second-Harmonic Gyrotrons

Shcherbinin

Moskvitina

Avramidis

et al. 2020

IEEE Trans. Electron Devices

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A coaxial metal rod with partial dielectric coating is considered as a means for efficient suppression of all volume competing modes in cavities for secondharmonic gyrotrons operated in whispering gallery modes. The rod radius is selected small enough to have only a slight effect on operating mode, which therefore remains insensitive to fabrication tolerances and a misalignment of the coaxial insert. By contrast, for the competing modes such a rod is shown to reduce the effective cavity length and thereby greatly increases the starting currents. Such a method of mode selection is demonstrated to be more versatile, as compared to that provided by a tapered coaxial conductor. The advantageous use of a dielectriccoated coaxial insert is illustrated by the example of a cavity for a 100-kW 300-GHz pulsed gyrotron operated in the second-harmonic mode.

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Analogy Between Circular Core-Cladding and Impedance Waveguides and Their Membrane Functions

Cited by 16 publications

References 46 publications

Mode Discrimination by Lossy Dielectric Rods in Cavities of Second-Harmonic Gyrotrons

Mode Discrimination by Lossy Dielectric Rods in Cavities of Second-Harmonic Gyrotrons

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

Improved Mode Selection in Coaxial Cavities for Subterahertz Second-Harmonic Gyrotrons

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