Dispersion analysis of three-fold helical rippled waveguide for 8 mm gyro-TWT and gyro-BWO

Three-fold helical rippled waveguide makes TE11 and TE21 coupling, the dispersion characteristic in physical mechanism make the electron the cyclotron resonance in the broad frequency band, so the dispersion equation need to be researched. The dispersion equation of the traveling wave mode and backward wave mode are put forward for the engineering application. The coupling coefficient of the dispersion equation is simplified, whose error is about 1%. The model is built and the helical rippled waveguide is simulated using VBA program in CST software. A simulation method is put forward by the coupling mode characteristic in the simulated transmission characteristic curve. The simulation result is compared with the theoretical one and the error is about 5%. The simulation method and theory in