Simulation of Microfabricated Folded Waveguide Traveling-Wave Tube as Broadband Terahertz Amplifier
Ruilin Zheng, Haisheng San, Xuyuan Chen
Asia Pacific Microwave Conference, 2009. APMC 2009.
1469 - 1472
Broadband amplifier, folded waveguide, simulation, terahertz, traveling-wave tube
In this paper, electromagnetic field simulations and related results of a 400GHz central frequency microfabricated folded waveguide traveling-wave tube were presented, for a broadband terahertz amplifier. 3-D cold-test (absence of real electron beam) and particle-in-cell simulations were carried out. Two models of different beam tunnel crosssection, i.e. cylindrical and rectangular, were simulated. It was found that the rectangular tunnel model is similar to the cylindrical tunnel model in cold-test properties, when the transverse square side length is 85% to the diameter of the cylindrical tunnel. The three-dB bandwidth is 40.6GHz and the maximum gain is 15.8dB at 393.3GHz, for an 18.5mm-long (60periods) loss-free circuit, predicted by Pierce small signal theory. Particle-in-cell simulation also revealed the three-dB bandwidth of ~35GHz and ~30GHz for cylindrical-tunnel model and rectangular-tunnel model, respectively, for a 29.6mm-long (96periods) loss-free circuit with concentrated attenuator. It is also found that the gain of rectangular-tunnel model is about 5dB lower than that of cylindrical-tunnel model, for 29.6mmlong
circuit. The loss-free saturated output power and the linear gain of cylindrical-tunnel model at 400GHz are 6.9W and 28dB, respectively.
Back to References