Demonstration of an Upgrading G-Band Rhombic Grating Slotted Sine Waveguide TWT

This is the authors' abstract. We don't add key points for this paper.

In this article, a novel rhombic grating slotted sine waveguide (RGS-SWG) is proposed for high-power terahertz traveling-wave tube (THz TWT), which has been conceived, fabricated, and tested. By reconfiguring a previously reported staggered U-shaped groove sine waveguide (SUGSWG) from a rectangular grating to a rhombus grating, the RGS-SWG represents the low ohmic loss (32% lower) and high interaction impedance (23% higher) under similar dispersion properties. Particle-in-cell (PIC) simulation results showcase that the maximum saturation output power and efficiency bandwidth product (EBP) of RGS-SWG TWT are 226 W and 148%⋅GHz, which are 26% and 32% larger than those of the SUGSWG TWT under the same operating voltage of 23 kV and current of 126 mA. Subsequently, a G-band electron gun and double periodic permanent magnetic focusing system were designed for a circular electron beam to pass through the circuit tunnel without being intercepted. Finally, the nano computer numerical control technology was used to realize the fabrication and transmission test of the novel RGS-SWG slow wave structure (SWS). The cold test results demonstrate that the ohmic loss at 220 GHz is 0.15 dB/mm, and the measurement results agree well with the theoretical design ofSparameters in the operating frequency band, which verifies the possibility of realizing this novel RGS-SWG structure and validates the remarkable potential in RGS-SWG TWTs for THz applications.