Rotary-tuned magnetrons

A new means of rapidly tuning magnetron oscillators by a continuous rotating motion has been developed, permitting tuning rates 10 to 50 times faster than was previously possible with these tubes. The technique offers either controlled or completely random frequency agility on a pulse-to-pulse basis, and retains the inherent magnetron advantages of small size and weight, high efficiency, and simplicity of design, leading to high reliability. By utilizing a continuously rotating tuner element, rather than the reciprocating elements formerly employed, problems of inertia, tuner drive power and drive system response are eliminated. A simple variable-speed rotary motor provides the driving force. The rotary tuning plate has been designed for adaptation to tubes at various frequency bands. Uses of the device are centered around ECCM applications, but have also been shown to offer radar range enhancement and avoidance of rf interference between electronic equipments. Information will be presented in this paper illustrating the construction and mechanical layout, as well as the electrical theory and performance results achieved with the new device. Techniques for fast-tracking with an electronically-tuned oscillator will be shown. The present state of the rotary-tuned magnetron art will be discussed, as well as probable limits and likelihood of future development in this area.