A field iterative method for computing the scattered electric fields at the apertures of large perfectly conducting cavities

An iterative method is developed for computing the scattered electric fields at the apertures of large perfectly conducting cavities. The field iterative method (FIM) uses Kirchhoff´s approximation to initiate a two stage iterative process (i.e., the method of successive approximations), involving both the magnetic field integral equation and the electric field integral equation, to calculate the electric currents on the internal cavity walls and the electric fields across the aperture of the cavity. The technique combines the flexibility of the boundary-integral method with the speed necessary to efficiently analyze large scale cavity problems. The paper presents the general theory, and applies the technique to the problem of TE scattering from two-dimensional perfectly conducting cavities