Geometrical and physical optics solutions for the backscatter radar cross section of tophat calibration targets

The problem of RCS calculation of tophat reflectors is revisited. A high frequency solution is obtained that allows for accurate RCS calculation of tophats with large to moderately large dimensions relative to the wavelength. It is shown that the traditional GO solution fails to predict the RCS with the desired accuracy, especially in the direction of maximum RCS. To improve the results, a second-order physical optics solution (PO-PO) is developed and is shown to predict the RCS more accurately. Also, the result is further enhanced by adding the contribution of edge diffraction from the cylinder top using the geometrical theory of diffraction (GTD)