Piecewise-Tunable Reflected Gyrotron

Tsun-Hsu Chang^1*, Cheng-Hung Tsai¹

¹Physics, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Tsun-Hsu Chang, email:thschang@phys.nthu.edu.tw

A reflective-type gyrotron is a promising source for frequency-sensitive applications. The generated backward wave is reflected at the cutoff section close to the gun end. We proposed a tapered structure operated at TE02 mode and centered at 203 GHz with the beam produced from a non-adiabatic electron source. Simulations carried out by our particle tracing, self-consistent code, and verified with the 3D commercial Computer Simulation Technology (CST) particle in cell solver, suggest a decent tuning bandwidth. Experimental data, surprisingly, shows an even broader bandwidth of 36 GHz by overlapping the adjacent waveguide modes, especially for the TE22 mode. The frequency tunability over a wide bandwidth demonstrates that the proposed reflective gyrotron is an excellent terahertz wave source.

Keywords: gyrotron, piecewise-tunable, non-adiabatic electron source, tuning bandwidth, terahertz