Electromagnetic field analysis of the wire antenna in the presence of a dielectric with three-dimensional shape

A numerical method which can take account of lossy dielectrics near the antenna has to be developed for the design of the radio-frequency antenna in magnetic resonance imaging, since the human body is a lossy dielectric. A combination of the moment method and the boundary element method is proposed. In the proposed method, the scattering field of dielectrics in the moment method is calculated by using the equations of the boundary element method, and the impressed field of current distribution in the boundary element method is calculated by using the approximation of the current distribution in the moment method. A helical antenna loaded with a cylinder was chosen as a calculation model, and the calculated results were compared with experimental results, verifying the method's applicability