Impedance Analysis of Printed Antenna on Three-Dimensional High-Permittivity Dielectric Substrate Using Mixed-Domain MoM

An integral equation approach with a new solution procedure using moment method (MoM) is applied for the computation of coupled currents on the surface of a printed dipole antenna and inside its high-permittivity three-dimensional dielectric substrate. The main purpose of this study is to validate the accuracy and reliability of the previously proposed MoM procedure by authors for the solution of a coupled volumesurface integral equations system. In continuation of the recent works of authors, a mixed-domain MoM expansion using Legendre polynomial basis function and cubic geometric modeling are adopted to solve the tensorvolume integral equation. In mixed-domain MoM, a combination of entiredomain and sub-domain basis functions, including three-dimensional Legnedre polynomial basis functions with different degrees is utilized for field expansion inside dielectric substrate. In addition, the conventional RaoWilton-Glisson (RWG) basis function is employed for electric current expansion over the printed structure. The accuracy of the proposed approach is verified through a comparison with the MoM solutions based on the spectral domain Green’s function for infinitely large substrate and the results of FDTD method. key words: volume integral equation, mixed-domain MoM, dielectric substrate, printed antenna, legendre expansion, FDTD method