: Because the interaction is not limited to resonant cavities, TWTs can achieve much larger bandwidths—often octave or decade ranges. General Vacuum Electronic Devices (VEDs) :
: It covers essential topics such as electron beam formation, focusing (Chapter 7), and the forces between electrons in the drift space. Distinguishing Technical Features of the Devices Discussed Principles of Klystrons, Traveling Wave Tubes, ...
The text you're referring to is the title of a standard textbook in the field of microwave engineering: by A. S. Gilmour, published by Artech House . Key Features of the Textbook : Because the interaction is not limited to
Based on the principles outlined in the text and related resources: : focusing (Chapter 7)
Exceptional points of degeneracy in traveling wave tubes - OUCI
: It represents the culmination of the author’s 50 years of industry experience.