Surface wave excitation by a waveguide aperture with an impedance flange

In this paper, the theoretical analysis of energy characteristics and radiation patterns of surface waves along the flat impedance flange exited by semi-infinite waveguide was carried out. The solution of problem was conducted using variation principle in the single-mode approach. Considering a semi-infinite cylindrical waveguide of arbitrary cross section, it is possible to build integral equation in the linear combination of the tangential components of electrical and magnetic field on the waveguide aperture. Formulas for calculation the surface wave excitation coefficient and radiation pattern of surface wave were obtainedasing variation principle. The numerical analysis of the surface waves characteristics exited along the impedance flange by coaxial and circular waveguides was conducted on the basis of obtained formulas.