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Field Theory of Traveling-Wave Tubes with Loss: Application to the Study of Attenuator Saturation Effects

Buchman, William (1955) Field Theory of Traveling-Wave Tubes with Loss: Application to the Study of Attenuator Saturation Effects. Electron Tube and Microwave Laboratory Technical Report, 2. California Institute of Technology , Pasadena, CA. (Submitted)

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Propagation constants have been calculated for a lossy traveling- wave tube by means of a field theory. These results have been applied to the prediction of an attenuator power loss of the order of 2 or 3 db. compared to attenuatorless operation. It is shown that the gain of the higher order modes is negligible. Admittance matching by means of radial admittance transformation is the underlying method used throughout. The Pierce-Fletcher theory in common use at this time is examined in some detail to determine its range of validity. It is found to break down when the ratio of beam to helix radius is almost unity and when p_(o)a is small. Furthermore, it is shown that complex parameters must replace the real ones, Q, K, and C, if one wants to extend the Pierce notation correctly to lossy tubes. Not doing so leads to discrepancies of approximately 10% in the propagation constants calculated here. There is reason to believe that parameters other than those used here will not result in greater discrepancy. The effects of space charge bunching on saturation has been treated. Criteria have been set for determining whether bunching is important or not in determining saturation.

Item Type:Report or Paper (Technical Report)
Alternate Title:Field Theory of Traveling-Wave Tubes with Application to the Study of Attenuator Saturation Effects
Additional Information:Without the continual advice and encouragement given by Dr. Lester M. Field, this project could never have been started or completed. Many discussions with Dr. Field and Roy W. Gould have helped shed much light on the attenuator and associated problems. T. E. Feuchtwang did some of the numerical and experimental work associated with the space charge bunching effects in attenuators. Much is owed to J. B. Opfell, W. G. Sly, R. A. Pasternak, and J. S. Rollett of the Chemistry and Chemical Engineering Division and to Jerry Cromb of I.B.M. for teaching the author how to use the computing machinery. Ruth Brown typed the final version of this report, a formidable task.
Group:Electron Tube and Microwave Laboratory
Funding AgencyGrant Number
Office of Naval Research (ONR)220(13)
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Electron Tube and Microwave Laboratory Technical Report2
Series Name:Electron Tube and Microwave Laboratory Technical Report
Issue or Number:2
Record Number:CaltechAUTHORS:20190212-133034502
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:92851
Deposited By: Melissa Ray
Deposited On:12 Feb 2019 22:51
Last Modified:03 Oct 2019 20:49

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