Parallel Arrangement Folded Double-Ridge Groove Waveguide for High-Power Terahertz Traveling-Wave Tube

In this article, a terahertz traveling-wave tube (TWT) with two identical folded double-ridge groove waveguides (DRGWs) operated in parallel is presented. Driven by a sheet electron beam in each DRGW TWT allows a higher beam current, and hence higher output power can be achieved. A magic T based on DRGW is designed as the input and output power couplers for this novel TWT. The performance of the magic T is optimized using Chebyshev impedance transforming structures. The simulated reflection and transmission coefficients of the whole tube with magic T in the operating frequency range of 330–350 GHz are less than −20 and −75 dB, respectively. In addition, a particle in cell (PIC) simulation of the beam–wave interactions involving the two sheet electron beams predicted an output power of 160 W at 340 GHz with a 3-dB bandwidth of 11 GHz when a beam of 27.68 keV in energy and 0.25 A in total current is used.