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This work was pursued to develop an electromagnetic solver code that predicts the Radar Cross section (RCS) of objects in the high frequency domain. This solver uses techniques of Physical Optics (PO) and Physical Theory of Diffraction (PTD) for RCS computation. The advantage of using such methods is that simulation can be undertaken for frequencies as high as 40 GHz, which becomes an effective tool to predict the stealth settings of aircrafts. The current work was of interest to our customers in defense laboratories, who needed to predict the RCS of objects like the LCA in the high frequency domain.
For this method, the scattered fields can be expressed in terms of the radiation integrals over actual currents induced on the surface of the scatterer. Also, the method assumes that the induced surface currents on the scatterer surface are given by the geometrical optics currents over those portions of the surface directly illuminated by the incident field, and zero over the shadowed sections of the surface.
The code was validated for standard IEEE cases like the conesphere, ogive, almond etc for computation of monostatic RCS values with varying source positions. The results obtained for co-polarization RCS values followed a similar trend and magnitudes when compared to reported results, for incident frequencies as high as 10 GHz.