Harmonic distortion in a traveling wave tube at 850 GHz and its use in frequency multiplication

Nonlinear behavior of a traveling wave tube operating at 850 GHz has been studied by performing 3D particle-in-cell simulations. The conversion efficiency to the second harmonic (1700 GHz) is more than 7% when an input signal power of 14 dBm is applied. Such a device could be used as a frequency doubler driven by a combination of a solid-state source and a traveling wave tube amplifier.