| A numerical technique employing the method of moments (MOM) and physical optics (PO) is presented for studying the scattering from a planar slotted waveguide array antennas . The slot scattering and structural scattering are solved independently through the application of the equivalence principle. The former is calculated by MOM . Special attention is paid to the evaluation of the admittance matrix elements, which involve the internal and external mutual coupling. The latter is solved using PO. Numerical results are given to demonstrate the effects of several factors including the number of basis functions, the thickness of waveguide, the terminations of waveguide and different frequency on the radar cross section (RCS) of a slot array. As a check of the method , numerical results are compared with earlier calculations. Agreement has been found to be quite satisfactory. The method in the article can be readily extended to the case of radiation from slot antennas. Finally,the scheme of equivalent conversion is presented about the rectangular slot and circular slot in the project and the analysis of conversion error is given. |
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