Radio Science

Basic features of the null field method for dielectric scatterers


  • Staffan Ström,

  • Wenxin Zheng


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.