A new technique for ultra-broad band high power TWTs

A new method of controlling the phase velocity dispersion characteristic by using the principle of anisotropic conductive circuit loading is described. The objective of extending the frequency band of helix traveling wave tubes (TWTs) is achieved by a very simple modification in the conventional interaction circuit, that is, a proper surface metallization of the helix supporting rods. It is shown that conventional helix tubes can easily be modified to obtain a remarkable extension of the lower portion of the operative frequency band. In comparison with the 'conventional vane loading' technique, the 'rod metallization' technique allows frequency band extension with no addition of parts and, what is more important, without affecting the circuit assembly operations.