Spectral representation of the Green´s functions for microstrip antennas on cylindrical substrates

It is well-known that the angular Fourier series is poorly convergent in a numerical implementation of the Green´s functions, especially for electrically large patches and cylinders. Using the theory of characteristic Green´s functions, the author represents the components of the Green´s dyad as spectral integrals over a continuum of angular and axial wavenumbers, thereby obviating the need for Fourier series. The angular periodicity that is intrinsic to an electric dipole located on a cylindrical microstrip substrate can be recovered from the spectral integrals by applying completeness relations for the angular-domain characteristic Green´s function.<>