The present effort in the area of high power traveling-wave tubes finds its common root in both klystron development and the original low power helix TWT development. This is in a sense natural, since the achievement of megawatt-type microwave devices was first demonstrated in a klystron1 whereas broadband amplification was first demonstrated in the low power helix TW tuve.2 Both types of devices use the velocity modulation principle, one in the form of standing waves, the other in the form of traveling-waves.
In addition, many similarities in the design of both devices, such as beam formation, extraction for electromagnetic energy, and beam collections, serve to provide a common background of development.
The discussion in this paper will deal primarily with linear beam devices with some reference to cross-field devices in order to give a fairly comprehensive picture of state of art in high power microwave tubes.
I. INTRODUCTION
Historical Background
