Electric field measurements in klystron cavities

This paper presents the experimental results of 0 / sh R Q measurements in klystron cavities using the perturbation technique. The theory involving this technique results in an expression which depends on the natural frequency 0 f and the perturbed frequency shift f Δ , both measured using a cylindrical reentrant cavity with offset gap built in the laboratory. In addition, it is used a cylindrical cavity (pill-box) to calculate a constant that depends on the geometry of the perturbed object, as well as analytical expressions to calculate an integral factor that relates the square of the voltage on axis and the electric energy originally stored in the small volume of the perturbed object. The values measured of 0 f , f Δ and 0 / sh R Q are, respectively, 2.86 GHz, -5.27 MHz and 79.8 Ω. They are also compared with the results simulated by a 3D eigensolver obtaining a good agreement. Keywords -Klystron cavity 0 / sh R Q , Slater's perturbation technique, cylindrical reentrant cavity, perturbed frequency shift.

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“…(17) Then, subtracting (17) from (16) and using the vector identity (7) it is possible to write that ( )…”

Section: Mathematical Formulationmentioning

confidence: 99%

“…Besides, experimentally, it is used the concept of the Slater's perturbation theorem, which states that, considering a small perturbing object along the axis, the magnetic field can be negligible [7] and the perturbed frequency shift, from (24), can be written as ( )…”

Section: Mathematical Formulationmentioning

confidence: 99%

R<inf>sh</inf>/Q<inf>0</inf> measurements in klystron cavities

Silva¹,

Lopes

Motta

2011

2011 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC 2011)

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“…Thus, a measurement scheme based on perturbation theory is provided to obtain the uniformity parameter value in this paper. Perturbation theory is generally used to measure dielectric constant of materials and the change in the resonant frequency of devices [19][20][21][22][23][24][25]. The most common perturbation methods include changing device structures and changing filling mediums [20].…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Resonator Part of a Ka-Band Multiple-Beam Extended-Interaction Oscillator through Electric Field Uniformity

Yin

et al. 2021

Electronics

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The development of multiple-beam devices is required due to the increasing demand of compact, high-frequency, and high-power vacuum devices. A Ka-band multiple-beam extended-interaction oscillator which operates in TM01 mode with a large diameter (as the value is 14.6 mm which is larger than the operating wavelength of 8 mm) to obtain high output power has been put forward. In previous studies, the performance differences of single-beam extended-interaction oscillator with different electric field uniformity can be as high as 70%. Simulation results predicted the multiple-beam device has an average output power of 7.594 kW when a total beam of 3 A, 18 kV and the uniformity parameter is 0.064. Meanwhile, it predicted that the difference of output power of multiple-beam devices with different field uniformity (corresponding uniformity parameter is within 0.064~0.278) is within 2.53% when other operating conditions are unchanged. The results show that the multiple-beam device substantially decreases the influence of the field uniformity, which is an important factor for the performance in the single-beam device. A cold test experiment has been carried out based on perturbation theory to obtain the electric field distribution curves of this device, and this provides a method for studying multiple-beam devices.

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Measurement of axial field distribution in a W-band extended interaction resonant cavity based on perturbation technique

Meng

Wang

et al. 2020

AIP Advances

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The theoretical analysis and the experiment of perturbation techniques to the quantitative measurement of electric field characteristics in a 94 GHz extended interaction resonant cavity (EIRC) are described. Parameters such as the observed reflection coefficient (S11) and resonant frequency at the disturbance point can be adopted to determine the Q-factor, relative electric field intensity, and distribution of the EIRC. In the experiment stage, the frequency deviation characteristics of the tested EIRC under the influence of the metallic sphere are consistent with the simulation results, and the relative error of the frequency deviation is 4.40%. This provides an effective solution for studies of the performance monitoring of millimeter–submillimeter-wave electronic devices and the exploration of high-frequency material science.

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Electric field measurements in klystron cavities

Cited by 3 publications

References 3 publications

R<inf>sh</inf>/Q<inf>0</inf> measurements in klystron cavities

R<inf>sh</inf>/Q<inf>0</inf> measurements in klystron cavities

Analysis of the Resonator Part of a Ka-Band Multiple-Beam Extended-Interaction Oscillator through Electric Field Uniformity

Measurement of axial field distribution in a W-band extended interaction resonant cavity based on perturbation technique

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