Frequency Tuning of a Magnetron of the 3-mm Wavelength Range Using an Additional Output

Abstract

The frequency tuning of a magnetron that operates on a spatial harmonic of the π/2–1 oscillation type was investigated. The mechanisms that limit the frequency-tuning range upon a change in the electric length of an additional (second) energy output were clarified and the possibilities of creating preferable conditions for exciting an operating oscillation mode by changing the external quality factor via rotation of the electromagnetic-field structure were determined. Based on calculations, experimental prototypes of magnetrons were manufactured and investigated. Long-term stable oscillations with a power of up to 11.5 kW were achieved. The tuning range using the second output is 300 MHz with a decrease in the output power down to 68% relative to the maximum power. The tuning range is up to 600 MHz at a power level of ~30% of the maximum and a reduced anode voltage.