Description and Characteristics of the End-Plate Magnetron

A new type of magnetron is described which is especially adapted to the generation of centimeter waves. It possesses several advantages over the simple magnetron, namely: (1) greater stability with respect to fluctuations of supply voltages, (2) less tendency to oscillate at undesired long wavelengths, (3) greater efficiency, (4) greater output, and (5) greater ease of adjustment. Static and dynamic characteristics are discussed. The effect of space charge on electron motion and tube performance is treated mathematically, and supporting experimental data are presented. Evidence is given that for best operation an optimum space-charge condition is required, which can conveniently be established and maintained by the use of end plates. Power output is limited by a type of instability involving electron bombardment of the filament, and apparently initiated by excessive space charge.