Search results for "Waveguide"
showing 10 items of 311 documents
Experimental Study of the Multipactor Effect in a Partially Dielectric-Loaded Rectangular Waveguide
2019
This letter presents the experimental study of the multipactor threshold in a partially dielectric-loaded rectangular waveguide, whose results validate a multipactor model recently developed by the authors, which includes the charge distribution appearing on the dielectric surface during the multipactor discharge. First, the variation of the multipactor RF voltage threshold has been theoretically analyzed in different waveguide configurations: in an empty waveguide, and also in the cases of a one-sided and two-sided dielectric-loaded waveguides. To reach this aim, an in-house Monte Carlo simulation tool has been developed. The Secondary Electron Yield (SEY) of the metallic and dielectric ma…
Analysis of Multipactor Effect in a Partially Dielectric-Loaded Rectangular Waveguide
2019
This paper 1 presents a study of the multipactor 2 effect in a partially dielectric-loaded rectangular waveguide. 3 To obtain the simulations presented in this paper, a detailed 4 analysis of the dynamics of the electron inside this waveguide 5 has been performed, taking into account the radio frequency 6 electromagnetic fields propagating in the waveguide and the dc 7 electric field that appears because of the charging of the dielectric 8 layer. This electrostatic field is obtained by computing the electric 9 potential produced by an arbitrary charge distribution on the 10 dielectric layer in a dielectric-loaded waveguide. The electron 11 trajectory is then found by numerically solving the…
Multipactor RF Breakdown in Coaxial Transmission Lines With Digitally Modulated Signals
2016
The aim of this paper is the study of the RF multipactor breakdown in coaxial transmission lines excited by a single carrier with a digitally modulated signal. Employing an in-house developed code, numerical simulations are performed to determine the RF multipactor voltage threshold for several digitally modulated signals under different modulations schemes: quadrature phase-shift keying, 16-quadrature amplitude modulation, 16-amplitude and phase-shift keying, and 32-amplitude and phase-shift keying. Moreover, a coarse method based on the envelope integration to determine the RF multipactor voltage threshold when involving arbitrary digital modulations is also presented. These results are a…
High power analysis and design of dual-mode channel filters
2009
In this paper, we present two dual-mode channel filter topologies which are able to withstand more than 600 W in Ku-Band. The two different designs (one with elliptical cavities and the other one with rectangular cavities) implement the same transfer function: four order, elliptical response centered in 12 GHz, with 40 MHz bandwidth and two transmission zeros. It is shown that the critical dimensions for the power-handling of these filters are the dimensions of the input-output irises. In fact, in order to rigorously obtain these conclusions and to reach these high-power levels (including margins), it is essential to use the advanced numerical techniques described in the paper to predict th…
Multipactor Effect in a Parallel-Plate Waveguide Partially Filled With Magnetized Ferrite
2014
The aim of this paper is the analysis of the multipactor effect in a parallel-plate waveguide when a ferrite slab, transversally magnetized by a static magnetic field parallel to the waveguide walls, is present. Employing an in-house developed code, numerical simulations are performed to predict the multipactor radio frequency voltage threshold in such a ferrite-loaded waveguide. Variations of the ferrite magnetization field strength and the ferrite slab height are analyzed. Effective electron trajectories are also shown for a better understanding of the breakdown phenomenon, finding different multipactor regimes.
Multipactor Mitigation in Coaxial Lines by Means of Permanent Magnets
2014
The main aim of this paper is the analysis of the feasibility of employing permanent magnets for the multipactor mitigation in a coaxial waveguide. First, the study of a coaxial line immersed in a uniform axial magnetic field shows that multipactor can be suppressed at any RF if the external magnetic field is strong enough. Both theoretical simulations and experimental tests validate this statement. Next, multipactor breakdown of a coaxial line immersed in a hollow cylindrical permanent magnet is analyzed. Numerical simulations show that multipactor can be suppressed in a certain RF range. The performed experimental test campaign demonstrates the capability of the magnet to avoid the multip…
Enhanced prediction of multipaction breakdown in passive waveguide components including space charge effects
2008
An enhanced prediction software tool of multipaction breakdown effect in passive waveguide components is proposed in this work. For such purpose, the space charge field effects are included employing a particle-in-cell code and finite differences in time domain integration techniques. As a result, the novel prediction tool models all the physical effects derived from multipactor such as reflected power, noise and/or harmonics, thus improving the accuracy of the threshold predictions and providing very valuable additional information of the phenomena. Such tool has been integrated within a full-wave modal analysis software for complex waveguide geometries (FEST3D), and the multipactor effect…
Multipactor Discharges in Parallel-Plate Dielectric-Loaded Waveguides Including Space-Charge Effects
2008
[EN] The objective of this paper is to study the time evolution of multipactor discharges in a parallel-plate dielectric-loaded waveguide. The electron discharge phenomena investigated in this paper include the effects of space charge, as well as the presence of time varying static fields. In order to perform the simulations presented in this paper, an approach considering simultaneously multiple effective electrons has been used. The results obtained demonstrate that multipactor discharges do turn off by themselves under certain circumstances when they occur in such dielectric-loaded structures.
Time evolution of an electron discharge in a parallel-plate dielectric-loaded waveguide
2006
The objective of this letter is to study the time evolution of a multipactor discharge in a simple dielectric waveguide structure. In particular, the investigation is performed on the case of a parallel-plate waveguide structure partially filled with a dielectric layer. The main consequence of the specific case studied in this letter is the fact that the dielectric layer charges negatively, allowing a negative static field to build up. This dc field eventually leads to a single-surface multipactor in the metallic surface before finally turning off the electron discharge.
Experimental Analysis of the Multipactor Effect With RF Pulsed Signals
2015
The main goal of this letter is the analysis of the multipactor effect within a coaxial waveguide excited by an RF pulsed signal. The variation of the multipactor RF voltage thresholdwiththe ON interval length of the pulse has been analyzed. To reach this aim, an in-house multipactor simulation code based on the Monte-Carlo algorithm has been implemented. The numerical simulations show that the multipactor RF voltage threshold increases as the ON pulse interval diminishes. In addition, an experiment was carried out to validate the proposed theoretical model, and demonstrating the excellent agreement between the theory and the experimental data. Finally, the results are compared with the 20-…