A Spatial Harmonic Traveling-Wave Amplifier for Six Millimeters Wavelength

This paper describes a traveling-wave amplifier in which the electron beam interacts with a spatial harmonic of an electromagnetic wave propagating along an array of resonator slots. The result is a considerable reduction in operating beam voltage for a given physical separation of the circuit elements. This type of amplifier operating at about 1,200 volts has yielded net power gains of about 18 db in the 6-mm wavelength region. A magnetic field of about 1,600 gauss is sufficient for proper beam focusing. Aside from small variations of gain with frequency caused by internal reflections, the bandwidth is of the order of 3 per cent.