Multiple scattering of EM waves by dielectric spheres located in the near field of a source of radiation

An analysis of multiple scattering of electromagnetic (EM) waves by two loss-free dielectric spheres with radii greater than a wavelength and located in the bear field of a source of radiation is presented. The incident field is expressed in terms of spherical vector wave functions (SVWF). Translational and rotational addition theorems are employed to express the SVWF of the incident field in the coordinate system associated with the dielectric scatterer. Numerical computations are performed for obtaining the amplitude and phase patterns of fields multiply scattered by two loss-free dielectric spheres, whose centers are located on the boresight axis and in the nearfield of an open-ended circular cylindrical waveguide excited in its dominant mode. Numerically computed results show good agreement with measured results obtained from a systematic experimental study on forward scatter performed in the -band.