INTERPOLATION, EXTRAPOLATION, AND APPLICATION OF THE MEASURED EQUATION OF INVARIANCE TO SCATTERING BY VERY LARGE CYLINDERS

Using the conventional method of moment (MoM) calculations, a cylinder of circumferential dimension of 100 wavelengths is considered to be l arge, Using the measured equation of invariance (MEI) approach, a cyli nder of 10 000 wavelengths is within the storage capacity and numerica l tolerance of a workstation, Although, the MEI has greatly reduced th e storage and solution time of the matrix, its overhead to generate th e matrix elements is about the same order as that of the MoM, When the target is very large, that overhead can be very time consuming, This paper presents an interpolation and extrapolation technique such that the boundary equations of MEI for high frequencies may be predicted fr om those of low frequencies, It is demonstrated that in the optical li mit the same set of coefficients may be used for all frequencies, whic h is consistent with the concept of geometric optics where the same ru le is applied to all frequencies.