A complete expansion set for free-space Green function using Kontorovich-Lebedev transform

Eigenfunction expansion of the free-space dyadic Green function using vector spherical wave functions is shown to be incomplete when the source is not located at the origin. Such incompleteness may result in inaccurate field computation. To resolve this issue, we present a complete eigenfunction set using the Kontorovich-Lebedev transform. This expansion set is employed to compute the electromagnetic field radiated by a circular current loop and verified by comparison with full-wave simulation.