Multipactor radiation analysis within a waveguide region based on a frequency-domain representation of the dynamics of charged particles

Abstract

A technique for the accurate computation of the electromagnetic fields radiated by a charged particle moving within a parallel-plate waveguide is presented. Based on a transformation of the time-varying current density of the particle into a time-harmonic current density, this technique allows the evaluation of the radiated electromagnetic fields both in the frequency and time domains, as well as in the near- and far-field regions. For this purpose, several accelerated versions of the parallel-plate Green's function in the frequency domain have been considered. The theory has been successfully applied to the multipactor discharge occurring within a two metal-plates region. The proposed formulation has been tested with a particle-in-cell code based on the finite-difference time-domain method, obtaining good agreement.

Analysis of the electromagnetic radiation generated by a multipactor discharge occurring within a microwave passive component

“…It should be remarked that the noise level associated with both m = 5 and m = 7 harmonics has been detected for the first time (to the best of the authors' knowledge) in a multipactor experimental set-up for telecommunication applications (the m = 9 harmonic is typically observed in the third-harmonic multipactor detection method). Another interesting aspect to be considered is the different trend of the radiated power spectrum between the parallel-plate model, which is continuously decreasing (as reported in [2,16]), and the results provided by the presented model, where the transmission coefficient of the DUT is directly included in the formulation. Finally, we want to remark that the discrepancies observed in figure 6 between the theoretical and measured data for such harmonics are attributed mainly to the single-mode character of the developed model.…”

“…2 z dimensions, respectively. As a consequence, such classical model has been used in this work for the description of a double-surface multipactor discharge [2,16].…”

“…This is the case for the central section of the E-plane waveguide transformer analysed in this work (see figures 2(a) and (b) and table 1), where the gap (oriented in the y direction) is approximately 60 and 125 times smaller than the x and z dimensions, respectively. As a consequence, such a classical model has been used in this work for the description of a double-surface multipactor discharge [2,16].…”

Simple model of the rf noise generated by multipacting electrons

“…A particular model must be developed for each particular rf circuit. Examples of simulations for some rf filter configurations can be found in [9][10][11][12].…”

Simulations of multipactor in circular waveguides

“…[1][2][3][4][5] These studies have resulted in development of various numerical tools capable of simulating multipactor in different geometries including parallel plates, 6,7 coaxial cables, [8][9][10] dielectric windows, [11][12][13] rectangular and wedge-shaped waveguides, [14][15][16] microstrip lines, 17 waveguide irises, [18][19][20] and rf filters and transformers. [21][22][23] A notable exception is multipactor breakdown in circular waveguides, which has been given scant interest, in spite of its technical importance. However, a relevant analysis of the problem can be found in Ref.…”