Analytical Field Calculation Involving Current Modes and Quadratic Phase Expressions

New analytical expressions for the computation of physical optics (PO) integrals in the analysis of scattered or radiated fields due to large objects are presented. The PO current is expanded in terms of current modes. Each current mode is defined by an exponential term whose amplitude and exponent are smooth functions. The analytical expressions are valid to compute the PO integral of modes with the exponent (phase) defined by means of quadratic functions. These expressions permit an accurate and efficient evaluation of the integrals over electrically large surfaces. Representative results showing the performance obtained are presented