Circular-electric-mode hybrid coupler

The circular-electric-mode hybrid coupler permits electromagnetic energy to be transferred from a circular waveguide, which supports a TE//0//1 mode, to a coaxial waveguide also supporting a TE//0//1 mode, or vice versa. The extent to which this transference occurs is controlled by a cylindrical-waveguide 'drift' region, which supports both a TE//0//1 and a TE//0//2 mode. The coupling mechanism is closely analogous to that which occurs in the more familiar rectangular-waveguide hybrid, or Riblet, coupler. The paper provides a theoretical description of such a coupler, the results of which are shown to be in agreement with measurement. The theory represents a new application of the moment method.