Computer characterisation of resonance modes of a magnetron cavity

Summary form only given. The characterisation of resonance modes is one of the important procedures in the ´cold test´ of a magnetron. This procedure has been modelled on an X-band magnetron by using a well-developed 3-D code called MAGIC3D. The relevant magnetron anode block comprises twenty-two slots with straps connecting alternative vanes at both ends, an axial output conductor coupled to the anode with eleven legs connected to alternative vanes; the cathode in the form of an inner cylinder is terminated at one end by a gap followed by a choke disc attached to the output conductor. The use of a fast Fourier transform (FFT) technique combined with the time-domain technique employed by the MAGIC3D code has proved to be more effective in obtaining the spectrum of resonance modes than the conventional eigen-mode searching technique.