Circular electric waves propagating through the circular waveguide containing a circumferentially magnetized ferrite cylinder

Non-reciprocal properties of the circular electric waves propagating through the circular wave guides containing coaxially a circumferentially magnetized ferrite cylinder bave been discussed mathematically. Numerical examples are illustrated especially with respect to the lowest circular electric,TE_{01}, mode. The optimum design formula for the field displacement isolator is derived. The method for determining the critical cutoff guide radius which suppresses the higher order sprious mode is also given and the practically convenient design charts are presented. As a result of the present analysis, it becomes make out that the cut-off frequency or the cut-off guide radius has no directivities.