BEAM-TYPE MICROWAVE TUBES WITH TAPERED STRUCTURES
Abstract
IT IS OF INTEREST TO KNOW THE EFFECT OF A TAPERED PERIODIC SLOW WAVE STRUCTURE IN A MICROWAVE TUBE, NOT ONLY UPON THE OSCILLATOR AND AMPLIFIER OPERATION AT PROPAGATING FREQUENCIES AWAY FROM CUTOFF BUT ALSO UPON THE OPERATION AT FREQUENCIES NEARA CUTOFF FREQUENCY. An analysis is developed in terms of resonant modes defined at the cutoff frequencies to study the undesirable cutoff oscillations near these frequencies. The tapered smooth backward wave oscillator and amplifier of the helix-electron beam type is studied from the point of view of coupled mode theory employing the W.K.B. (Wentzel-Kramers Brillouin) method of solution, to see how the starting current for oscillation is affected. The Method of Alternate Expansions (MAE) is developed for cavity chains, both cold and hot, with the object of studying the cutoff oscillations which exist at frequencies where the chain is strongly resonant. A study was also made of the small-signal waves in an untapered centerhole-coupled structure interacting with a beam near cutoff. It is concluded that a practical taper of these structures would eliminate or drastically reduce the cutoffoscillation level, particularly in the higher voltage range of amplifier operation. ((Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1961
- Accession Number
- AD0272118
Entities
People
- Robert M. Bevensee
Organizations
- Stanford University