Design and Performance of a One Megawatt, 3.1 - 3.5 GHz Coaxial Magnetron

This paper describes a one megawatt coaxial magnetron which is mechanically tunable over a 12% frequency range. A new mode control technique for suppression of competing cavity modes is employed. Spurious signals are reduced to better than 55 dB below the peak output power of the tube via this mode control approach. Design of the interaction space of the coaxial magnetron is also discussed relative to improving starting stability and spectrum characteristics. The operating voltage of the tube is less than 40 kV, duty factor is 0.00067, efficiency is 50%, and tube weight is 600 N. Data on pushing, pulling, spectrum width, and stability are presented.