Finite-element analysis of phased-array antennas

The finite-element method (FEM) is applied to the analysis of phased-array antennas. Curvilinear tetrahedral elements are used for domain discretization and high-order vector basis functions are used for field expansion. Periodic boundary and radiation conditions are enforced on a single unit cell in the infinite array. A waveguide port condition is also implemented to accurately model the field on the aperture of the coaxial line that provides excitation. The asymptotic waveform evaluation (AWE) technique is combined with the FEM to perform fast-frequency and angular sweeps. The computed antenna parameters are compared with previously published results and good agreement is obtained. The effects of different feeding schemes on the array parameters are studied and compared. Frequency responses and scan performance of a flared-notch antenna design are presented. Finally, a preliminary investigation is made on the validity of the infinite-array approximation to the corresponding finite-array problems.