A wideband power mixer tube

The use of a traveling-wave tube¹ as a power mixer employing phase modulation at a single frequency has been described by W. J. Bray.² To use the same modulation principle with a wide band of modulation frequencies (hundreds of megacycles), excessive modulating power would be needed. This paper presents theory and experimental data for a broad-band traveling-wave type mixer requiring low modulating power. It consists of an input helix, a drift tube and an output helix arranged successively along a beam. Low modulating voltage is realized by operating the drift tube at low potential; the output helix is operated at high potential so the required power output can be obtained.