Field solution and electrical characteristics of slotted waveguides

The tangential field on the surface of a narrow axial slot on the wall of a hollow circular, or a coaxial waveguide, due to an incident TE11 mode is obtained. The slot is assumed to be semi-infinite in length and located symmetrically in the E-plane. A solution for the fields in the solid and the slotted protions of the waveguide, as as well as in the slot itself, is ontained by assuming proper wave functions with unknown coefficients in both waveguide sections. The unknown coefficients are determined from the two matrix equations obtained by applying the continuity condition to the transverse fields at the boundary between the solid and the slotted portions of the waveguide. The coefficient values are then used to determine reflection and transmission coefficients and the slot field which satisfies the edge conditions. The results are also extended to the case of two indentical and diagonally-symmetric slots. In a similar manner, the problem of a slotted coaxial waveguide is also solved, and the corresponding results are presented.