Method of moments analysis of EM fields in a multilayered spheroid radiated by a thin circular loop antenna

This paper presents derivation and computation of electromagnetic (EM) fields inside a dielectric prolate spheroid radiated by a loop antenna. The dielectric spheroid is considered to be multilayered, and a thin circular loop antenna that is loaded by a voltage source radiates on the top of the prolate spheroid. The multiple interaction of transmitted and reflected waves with the spheroid is characterized by applying the method of moments (MoM) to both the circular loop antenna wire and the stratified spheroidal interfaces. The dyadic Green´s function in the expansion form of eigenvector wave functions is used to derive the EM fields, so the formulation is quite compact. Different basis and weighting functions are used inside the method of moments procedure for obtaining in an efficient way the unknown current distributions along the antenna wire and the unknown expansion coefficients of their resulted EM fields. Current distributions and the transmitted fields inside the spheroidal model are computed numerically and the convergence issues are discussed.