Analysis of Magnetron Oscillations at Low Magnetic and Electric Fields

摘要

Research was undertaken to investigate the possibility of operating a multicavity magnetron at values of electrical and magnetic field near the characteristic values. This would make possible the scaling of the magnetron to very short wavelengths before encountering difficulties with anode heating and magnetic field limitations. The essential change in design for low field operation is the use of a small cathode diameter. An account is given of a familiar theoretical concept of ordinary magnetron operation and this is related to the operation at low fields. Electron trajectories are calculated for low field conditions. The theoretical concept of low field operation is in general agreement with experimental results obtained at this laboratory. Experimental results are given for an 18 segment anode. It is essential that a cut-off curve be obtained to allow for low field oscillations. The violation of the Hull cut-off relation at high voltage places a limitation on the voltage at which it is possible to design low field magnetrons. (Author)