Investigation of terahertz sheet beam traveling wave tube amplifier with nanocomposite cathode

Abstract

Particle-in-cell simulations of a staggered double grating array traveling wave tube intended as a wideband amplifier for terahertz communications, sensing, and imaging applications showed that, for an electron beam power of 5 kW, it produces 150–275 W, corresponding to 3%–5.5% electronic efficiency, at 0.22 THz with over ∼30% bandwidth and with greater than 12 dB/cm growth rate. The circuit has been fabricated by both UV lithography and high precision computer-numerical-control machining with ∼2–3 μm dimensional tolerance and ∼50 nm surface roughness. A scandate nanocomposite (Sc2O3–W) cathode for the electron beam source has successfully emitted 120 A/cm2 (space charge limited) at 1150 °C and 50 A/cm2 at 1050 °C for 8000 h as required to produce the requisite high current density electron beam.