Theoretical research on power handling capacity of the modes TM01 and TM02 in corrugated waveguides

This paper studies the power handling capacity of the modes TM01 and TM02 in circumferentially corrugated waveguides through analytical research on the evolution of the field distribution and the corresponding dispersion with an overmoded ratio. As the overmoded ratio grows at the constant frequency, the total electric field of the volumetric wave, in which the amplitude of the axial electric field reaches its peak value on the central axis and declines along the r-axis, gradually concentrates toward the corrugated surface; the volumetric wave is then converted into a surface wave. Such conversion does not completely prevent, but weakens the enhancement of the power handling capacity caused by augmentation of the overmoded ratio. Moreover, due to the effect of the longitudinal mode transition, the power handling capacity of the modes TM01 and TM02 does not monotonically increase as the overmoded ratio grows with the constant frequency. Such longitudinal mode transition counteracts, to some extent, the enhancement of the power handling capacity caused by augmentation of the overmoded ratio. Even when the average radius of the corrugated waveguide is only a little larger than the cutoff radius of the required frequency, the power handling capacity decreases dramatically with augmentation of the overmoded ratio. A comparison between the different types of ripple demonstrates that a smaller corrugation pitch results in a lower power handling capacity. The advantage of the power handling capacity of the TM02 mode over that of the TM01 mode is proved by a careful comparison between the different cases.