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Broadband Amplification of Low-Terahertz Signals Using Axis-Encircling Electrons in a Helically Corrugated
W He1, C R Donaldson1, L Zhang1
1Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, United Kingdom.
Abstract:
Experimental results are presented of a broadband, high power, gyrotron traveling wave amplifier (gyro-TWA) operating in the (75-110)-GHz frequency band and based on a helically corrugated interaction region. The second harmonic cyclotron mode of a 55-keV, 1.5-A, axis-encircling electron beam is used to resonantly interact with a traveling TE_{21}-like eigenwave achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain bandwidth of at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive source with a measured unsaturated output power of 3.4 kW and gain of 36-38 dB. The approach may allow a gyro-TWA to operate at 1 THz.
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