Radiation from a Terminated Parallel Plate Structure with Two Interacting Discontinuities

摘要

The radiation and impedance characteristics of two parallel plate waveguides, with a common center conductor, protruding a finite distance b over an infinite ground plane, are studied. The excitation of the two waveguides is either symmetric or antisymmetric with respect to the dividing protruding plane. The TEM mode is the only one propagating in both guides. The problem of antisymmetric excitation is formulated by means of two coupled integral equations, involving the radial electric field at the aperture and the angular component of the electric field at the termination of the protruding plane. The coupled integral equations are reduced to an infinite system of equations with infinite number of unknowns, and are solved approximately. For the case of symmetric excitation, symmetry considerations reduce the problem to only one discontinuity, namely, the aperture. Variational expressions for the driving point input admittance are given for both types of excitation. The results are shown for computations of the driving point input admittance, for both types of excitations, and for several values of kb and ka (a: aperture width), obtained from the approximate solution of the system of equations. These values are compared to those obtained from the variational expression, assuming a unity trial function. (Author)