Basic features of the null field method for dielectric scatterers

The null field approach to electromagnetic scattering from a dielectric body is presented in its general form, i.e., for a general choice of surface field expansions. Vector spherical harmonics are used to construct tangential fields which are shown to be complete for star‐shaped surfaces. The numerical performance of these sets is compared to that obtained when expansions in terms of different kinds of spherical vector waves are used. A demonstration of the uniqueness of the solutions to the null field equations for a permeable body is included in an appendix.