Computational investigation of experimental interaction impedance obtained by perturbation for helical traveling-wave tube structures
Conventional methods used to measure the cold-test interaction impedance of helical slow-wave structures involve perturbing a helical circuit with a cylindrical dielectric rod placed on the central axis of the circuit. It has been shown that the difference in resonant frequency or axial phase shift...
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Published in | IEEE transactions on electron devices Vol. 45; no. 9; pp. 2063 - 2071 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Legacy CDMS
IEEE
01.09.1998
Institute of Electronic and Electrical Engineers |
Subjects | |
Online Access | Get full text |
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Summary: | Conventional methods used to measure the cold-test interaction impedance of helical slow-wave structures involve perturbing a helical circuit with a cylindrical dielectric rod placed on the central axis of the circuit. It has been shown that the difference in resonant frequency or axial phase shift between the perturbed and unperturbed circuits can be related to the interaction impedance. However, because of the complex configuration of the helical circuit, deriving this relationship involves several approximations. With the advent of accurate three-dimensional (3-D) helical circuit models, these standard approximations can be fully investigated. This paper addresses the most prominent approximations made in the analysis for measured interaction impedance by Lagerstrom (1957) and investigates their accuracy using the 3-D simulation code MAFIA. It is shown that a more accurate value of interaction impedance can be obtained by using 3-D computational methods rather than performing costly and time consuming experimental cold-test measurements. |
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Bibliography: | CDMS Legacy CDMS ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0018-9383 1557-9646 |
DOI: | 10.1109/16.711375 |