Finite Element Analysis of Complex Antennas and Arrays

Various technical issues are addressed in the frequency- and time-domain finite element analysis of complex antennas and arrays that may consist of fine structures and composite materials. The paper starts with the finite element formulation of a generic antenna problem. Formulation for the modeling of general electrically and magnetically dispersive, lossy, and anisotropic materials in the time-domain finite element analysis is presented for the first time. This is followed by discussion of three typical techniques for truncation of the finite element computational domain via the use of absorbing boundary conditions, perfectly matched layers, and boundary integral equations. It then describes the modeling of antenna feeds using a current probe (including an improved model), a voltage gap, and a waveguide port boundary condition. After that, numerical approaches to modeling infinite phased arrays, large finite arrays, and antenna-platform interaction are presented, including two novel domain decomposition algorithms in both the frequency and time domains. Numerical examples are given to demonstrate the capability and application of the finite element analysis of a variety of complex antennas and arrays.