Design and nano-CNC fabrication of modified sine waveguide for 300 GHz traveling-wave tube

A sine waveguide is a slow-wave structure proposed recently for terahertz traveling-wave tube. The sine waveguide is known to have better transmission and reflection characteristics compared to slow-wave structures. There are several ways of fabricating terahertz slow-wave structures. A nano-CNC machining is a technique that has a couple of advantages over other methods. For fabrication to be possible, the sine waveguide should be modified. Simulations were conducted to compare the original and modified structures. The results show that S-parameters and dispersion curve are similar. The measurement of S-parameters of fabricated structure was done using a vector network analyzer. The measurement result shows that high transmission loss exists in the measurement result. The transmission loss in the modified sine waveguide will be analyzed in the future.