Author :
Camacho, J. Frank ; Rosenbury, E.T. ; Poole, B.R.
Abstract :
Summary form only given. A backward-wave oscillator (BWO) experiment using a slow-wave structure which consists of a nonsinusoidal corrugated-wall waveguide was designed. The period of the structure is z0=1.67 cm, with rmin=1.17 cm, rmax=1.97 cm, and length L=15.03 cm (nine periods). An annular electron beam with the following parameters is injected: Vbeam=1 MV, 1 kA ⩽Ibeam ⩽7 kA, rbeam=0.7, 0.8, or 0.9 cm, and tpulse≈60 ns. The guiding axial magnetic field is varied from 0.6 T to 3.0 T. The BWO is designed to operate at 8.0 GHz<f<8.5 GHz in the lowest-order TM mode of the coupled beam-structure system. A parameter scan in beam current, beam radius, and magnetic field, was carried out, showing how the BWO output power, operating frequency, bandwidth, and efficiency vary as a function of these variables. Of particular interest to this work is the phenomenon of premature microwave pulse termination and the nature of this effect in the experiment considered (especially at higher microwave power levels)
Keywords :
backward wave tubes; microwave generation; microwave oscillators; 0.6 to 3 T; 1 MV; 1 to 7 kA; 8 to 8.5 GHz; BWO output power; X-band backward-wave experiment; annular electron beam; backward-wave oscillator; guiding axial magnetic field; lowest-order TM mode; microwave generation; nonsinusoidal corrugated-wall waveguide; premature microwave pulse termination; slow-wave structure;
