CUTOFF FREQUENCIES OF GUIDING STRUCTURES WITH CIRCULAR AND PLANAR BOUNDARIES

The paper presents a method of evaluation of cutoff frequencies of a g uiding, structure consisting of two eccentric circular arcs with edges shorted by conducting planes. Combination of conformal transformation and method of finite difference is used for the analysis. The general formulation is applied to the limiting cases of lunar guide and also the guiding structure of semicircular cross section with a semicircula r dent along its diameter. Numerical data for TE and TM modes are pres ented for different angular separation between the shorting:planes, di stance between the centers and ratio of radii.