Exact solution for asymmetric mode excitation of open-ended coaxial waveguide with centre conductor of infinite extent and applications

A thin-walled coaxial waveguide open at one end and having the center conductor extending to infinity in the forward axial direction is studied for asymmetric mode excitation. After satisfying the boundary conditions on the structure the resulting equations are solved exactly by the Wiener-Hopf technique using Weinstein's approach. From this solution expressions are obtained for the coefficients of the modes excited in the waveguide and for the far fields radiated from the open end of the guide. Explicit results are given for the reflection coefficient and for far-field radiation patterns for TE//1//1 mode excitation. Experimental results demonstrate the validity and accuracy of the solution. Using these results we assess the performance of a thin-walled coaxial waveguide for possible application as a self-supporting feed for a reflector.