Low-voltage operation of the retarding-field oscillator at X band and in the millimeter wavelength region

This paper concerns the partial development of two low-voltage designs of the retarding-field oscillator. These designs differ fundamentally in their power coupling system. The
X
-band model has coaxial-line coupling to a waveguide while the millimeter wavelength model has double-cavity coupling to a waveguide. The design developed at
X
band allows operation with the anode voltage as low as 200 volts and as high as 600 volts. Radio-frequency output power of 20 milliwatts at 200 volts and better than 1 watt at 600 volts is possible. In the millimeter wavelength range, three double-cavity designs have been investigated. These tubes operate in the range of from 4.30 to 5.20 mm, 5.00 to 6.4 mm, and 5.80 to 6.8 mm, respectively. All of these oscillators have anode potentials of 800 volts or less. An output power of 175 milliwatts has been obtained at a wavelength of 6.00 mm. A digest of characteristics possessed by important models of the retarding-field oscillator investigated as of November, 1957, also is included.