Magnetron Theory of Operation CPI. I（磁控管的理论操作CPI。）.pdfVIP

Beverly Microwave Division /bmd Magnetron Theory of Operation A magnetron is a high power microwave oscillator in In order to sustain oscillations in a resonant circuit, which the potential energy of an electron cloud near it is necessary to continuously input energy in the the cathode is converted into r.f. energy in a series correct phase. Referring to Figure 2, if the instanta- of cavity resonators similar to the one shown in neous r.f. field, due to steady state oscillations in Figure 1. As depicted by the low frequency analog, the resonator, is in the direction shown, and, an the rear wall of the structure may be considered the electron with velocity was to travel through the r.f. inductive portion, and the vane tip region the capac- field such that the r.f. field retarded the electron itor portion of the equivalent resonant circuit. The velocity by an amount, the decrease in electron resonant frequency of a microwave cavity is there- energy will be exactly offset by an increase in the r.f. by determined by the physical dimension of the field strength. resonator together with the reactive effect of any In a magnetron, the source of electrons is a heated perturbations to the inductive or capacitive portion cathode located on the axis of an anode structure of the equivalent circuit. This is an important point