Technique for harmonic power reduction and efficiency enhancement in octave bandwidth TWT´s

Efficiency degradation and excessive second harmonic power content frequently beset the performance of TWT´s operating over an octave bandwidth. These difficulties can be surmounted upon application of a velocity-shift technique. Introduction of a circuit phase velocity-shift at intermediate levels of beam modulation provides effective means for substantial reduction (10 to 15 dB) in harmonic power content at tube saturation. More importantly, a considerable efficiency enhancement (by nearly a factor of two) is experienced over the entire band with the added benefit of notable improvement in BWO stability.