RCS of waveguide cavities: a hybrid boundary-integral/modal approach

The author presents a hybrid boundary-integral method (BIM)/modal approach for analyzing the scattering from open cavities that consist of uniform waveguide sections connected by arbitrary discontinuity regions. The BIM/modal approach entails determining the generalized scattering matrix of the discontinuity region by the BIM. Once the generalized scattering matrices of the individual sections are found, they can be cascaded to form the scattering matrix of the composite structure. Finally, the radar cross section of the open cavity is found by a reciprocity formulation in conjunction with the Kirchhoff approximation. Numerical results generated using the hybrid BIM/modal approach and experimental measurement for an offset bend at 10 GHz are compared, and excellent agreement is obtained.<>