Study of high frequency characteristics of the coaxial-radial line

An all-metal slow wave structure, coaxial-radial line, which is suitable for application in broadband high power traveling wave tube and relativistic TWT as a RF system is introduced. The dispersion equation of coaxial-radial line under the condition of neglecting the thickness of disk is given. It is analyzed that the change of the structure parameter affects dispersion properties and interaction impedance. The results show that the coaxial interlaced structure could make the bandwidth wider, the dispersion property weakens and interaction impedance increase as the inner conductor and displacement of the loaded disk enlarge. Because the coaxial-radial line has the advantage of weak dispersion, high power capability, it has a large potential application in high power microwave device.