Large-signal characteristics of a wide-band dielectric-loadedgyro-TWT amplifier |
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Authors: | Leou KC McDermott DB Luhmann NC |
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Institution: | Dept. of Electr. Eng., California Univ., Los Angeles, CA; |
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Abstract: | The bandwidth of a gyrotron traveling wave amplifier (gyro-TWT) has been significantly increased by partially filling the interaction waveguide with dielectric to reduce the circuit's dispersion. The proof-of-principle experiment was designed for X-band, and employs the fundamental mode of rectangular waveguide loaded with dielectric slabs along the narrow sidewalls. The amplifier yields a peak output power of 55 kW with 11% efficiency, 27 dB saturated gain, and an unprecedented untapered gyro-TWT constant-drive bandwidth of 11% and saturated bandwidth exceeding 14%. The single-stage amplifier is completely zero-drive stable. The 95-kV 5-A electron beam was produced by a single-anode magnetron injection gun with p⊥/υz=0.6, as determined by the EGUN code, and Δυz/υz=4%, determined as the best fit to the gyro-TWT large-signal simulation data. Simulation studies predict that by lowering the velocity spread to Δυ z/υz=2%, the amplifier performance will be further enhanced to a constant-drive bandwidth of 20% with 15% efficiency |
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