A Hybrid Dispersion Slow Wave Structure for 0.66 THz Traveling Wave Tubes

A novel concept of hybrid dispersion slow wave structure (HD SWS) is reported. It is realized by alternatively connecting SWSs operating at the regions of relatively strong dispersion (SD) and relatively weak dispersion (WD). In this way, the HD SWS will be characterized by high interaction efficiency over a moderate bandwidth. The equivalent dispersion of the HD SWS is calculated, which is affected by the periods’ proportion of the WD and SD SWSs. Driven by an ideal beam of 16.0 kV, 20 mA, and an input power of 1 mW, the hot performance of the HD SWS is conducted by using particle-in-cell (PIC) method. Compared with the SD SWS, the 3dB bandwidth and maximum power have been expanded and improved by 51.6% and 32.6%, without significantly increasing the circuit length. Compared with the WD SWS, the saturated interaction length has decreased by 31.1% at 0.661 THz, releasing the electro-optical system constraints. The HD SWS shows great potential to improve the terahertz (THz) vacuum electron devices’ performance.