A 250 GHz Photonic Band Gap Gyrotron Amplifier

POSTER

Abstract

Initial results for a high power 250 GHz gyrotron traveling wave tube (gyro-TWT) amplifier will be presented. The amplifier uses a novel photonic band gap (PBG) interaction circuit that confines the TE$_{03}$-like mode for operation. Stability from oscillations in lower order modes is provided by the PBG circuit. At 26.6 kV and 0.25 A the gyro-TWT operates with peak small signal gain of 27.3 dB at 251 GHz. The instantaneous -3 dB bandwidth of the amplifier at peak gain is 0.4 GHz. The amplifier can be tuned for operation from 245-254 GHz. A peak output power of 7.5 W has been measured. Experimental results taken over a wide range of parameters, 15-30 kV and 0.25-0.5 A, show good agreement with a theoretical model in the small signal gain regime. The theoretical model incorporates cold test measurements for the transmission line, input coupler, PBG waveguide and mode converter.

Authors

  • Emilio Nanni

    PSFC MIT, Massachusetts Institute of Technology, Plasma Science and Fusion Center, MIT, Cambridge, MA, USA

  • Samantha M. Lewis

    Massachusetts Institute of Technology

  • Michael Shapiro

    Plasma Science and Fusion Center, Massachusetts Institute of Technology, PSFC MIT, Massachusetts Institute of Technology, Plasma Science and Fusion Center, MIT, Cambridge, MA, USA

  • Richard Temkin

    Plasma Science and Fusion Center, Massachusetts Institute of Technology, PSFC MIT, Massachusetts Institute of Technology, Plasma Science and Fusion Center, MIT, Cambridge, MA, USA