Two high-frequency methods (UTD & BDW) for predicting the collective radiation by large finite planar arrays

Two efficient high-frequency (HF) methods, namely, a uniform geometrical theory of diffraction (UTD) and a boundary diffraction wave (BDW) method, for predicting the collective radiation from large finite planar antenna phased arrays are reviewed. The current distribution over the whole array for a given excitation is first obtained from a moment method (MoM) solution of the governing array integral equation. A traveling wave (TW) basis set is then used to represent the MoM based array distribution to facilitate an asymptotic HF analysis based on the UTD and BDW, respectively, to predict the "collective" radiation (or scattering) from the whole array at once. An asymptotic reduction of the BDW leads to the UTD. Both the UTD and BDW solutions provide a physical picture for the array radiation mechanisms.