One of the methods of analyzing phased-arrays is to assume that the array is infinite. The method of moments (MOM) is limited by the available Green's functions and by convergence problems in the summation of doubly infinite series originating from the singular periodic Green's function. The application of the finite element method (FEM) to infinite array analysis offers many advantages. First, complicated geometries and materials can be analyzed, where no analytic Green's functions are available. Second, the FEM is a general tool that avoids the need to develop new codes for new radiators. Third, since only one unit cell with phase-shift walls is analyzed, the model size fits the computational capabilities of present workstations. This paper describes the application of absorbing boundary conditions (ABCs) and complex periodic boundary conditions for a double-periodic phased array antenna fed by a plugged waveguide. The scan is performed in the H-Plane. The unit cell consists of the waveguide feed and a dielectric sheath plugged into the aperture. The ABCs are placed in some distance away from the aperture and absorb the generated plane waves of the periodic structure. Complex periodic boundary conditions sustain the propagation of the plane waves at the model's side walls. Results of reflection coefficient versus phase shift agree well with the MOM results for a wide range of phase shifts.
展开▼
