The coaxial magnetron: A wideband electronically-tunable oscillator

The paper describes the development and performance of an experimental coaxial magnetron. The tube is electronically tunable over a very wide frequency range and, except for harmonic output, can be used as a low-power oscillator with a bandwidth of at least 4 to 1. The tube, a smooth-anode magnetron, is a coaxial structure with an emissive center conductor and an axial magnetic field. It operates in what is termed an electronic mode rather than the traveling-wave mode of cavity magnetrons. Features of this tube, aside from operational characteristics, are simplicity, rugged construction, and practical size. A tube of this type, designed to cover 300 to 1000 mc, is much smaller than other local-oscillator tubes scaled for this frequency region.