Title :
Stability of a 95-GHz slotted third-harmonic gyro-TWT amplifier
Author :
Chong, C.K. ; McDermott, D.B. ; Lin, A.T. ; DeHope, W.J. ; Wang, Q.S. ; Luhmann, N.C., Jr.
Author_Institution :
Dept. of Appl. Sci., California Univ., Davis, CA, USA
fDate :
6/1/1996 12:00:00 AM
Abstract :
A low-magnetic-field moderate-voltage gyrotron amplifier has been designed for stable high-performance operation at 95 GHz. A slotted interaction circuit is utilized to achieve strong amplification near the third cyclotron harmonic frequency. The start-oscillation conditions were determined by an analytical theory and confirmed by a multimode particle-in cell simulation code. The dominant threat to the amplifier´s stability is from a third-harmonic peniotron backward-wave interaction. A slow-timescale particle-tracing simulation code predicts the three-section slotted third-harmonic gyro-TWT, which utilizes an 11.6-kG magnet and a 50-kV 3-A υ⊥/υz=1.4 axis-encircling electron beam with an axial velocity spread of 6% will yield an output power of 30 kW with an efficiency of 20%, a saturated gain of 40 dB, and a constant-drive bandwidth of 2%
Keywords :
gyrotrons; millimetre wave power amplifiers; simulation; stability; travelling wave amplifiers; travelling wave tubes; 11.6 kG; 3 A; 30 kW; 40 dB; 50 kV; 95 GHz; analytical theory; constant-drive bandwidth; design; electron beam; gyrotron amplifier; low-magnetic-field; moderate-voltage; multimode particle-in cell simulation code; slotted interaction circuit; slotted third-harmonic gyro-TWT amplifier; slow-timescale particle-tracing simulation code; stable high-performance operation; start-oscillation conditions; third cyclotron harmonic frequency; third-harmonic peniotron backward-wave interaction; Analytical models; Circuit simulation; Circuit stability; Cyclotrons; Frequency; Gyrotrons; Magnetic analysis; Operational amplifiers; Predictive models; Saturation magnetization;
Journal_Title :
Plasma Science, IEEE Transactions on
