A modal series representation of spatial‐domain electric field Green's functions for arbitrarily oriented electric current sources embedded in shielded multilayer media is presented. The Green's functions associated with planar excitations are briefly recalled, and the method to compute them is generalized to vertical current sources, yielding new components of the Green's function necessary for the analysis of vertical metallizations embedded in waveguides or cavities. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 33: 186–191, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10272