Reflections on the electric dyadic Green´s function, its singularity, and the potential method

Summary form only given. A review of contributions made in the area of the electric dyadic Green´s function is given. The distributional interpretation of the irrotational component of this dyad, a free space spectral expansion, and results obtained by analytically evaluating the spectral integral through contour integration are reviewed. It is also shown that away from the source one may represent the electric field in terms of the solenoidal vector wave functions alone, but the coefficients of these expansions must be modified to account for the contribution previously due to the irrotational vector wave functions. These results have been extended to spherical and cylindrical coordinates. A discussion of the pros and cons of potential methods versus field dyadic Green´s function methods is given. Potential methods have enabled the development of general-purpose codes such as the EIGER (Electromagnetic Interactions Generalized) code. As an illustration some sample results involving slot subcell models and cavity coupling problems are given.