Electronic Tuning of High Power X-Band Magnetrons with Ferrites

Frequency agile magnetrons are important in radar systems employing transmitter frequency agility to provide improvement in glint, fading and clutter. Electronic tuning is preferred for reasons of speed and reliability, and as such, it has high potential for such applications. Electronic tuning using ferrite-loaded cavities is the best method compared to others, specially at X-band frequencies. Tests were made on high power magnetrons, type 7008, to determine such capabilities. A rectangular waveguide cavity containing suitably located ferrite strips, was coupled through a matching section to one of the resonators of the magnetron. By varying a properly oriented biasing magnetic field, Ha, from 0 to 2000 oersteds, a frequency agility band, ¿F, of 65 to 55 MHz was obtained in the mechanically tunable band of 8.5 to 9.3 GHz, while the magnetron was operating within the specified limits. This agility band is atleast double of what can be obtained by other electronic methods.