A new hybred method for the analysis of the scattering and radiation by conformal antennas and arrays. The method employs a finite element formulation within the cavity and the boundary integral (exact boundary condition) for terminating the mesh. By virtue of the finite element discretization, the method has no restrictions on the geometry and composition of the cavity or its termination. Furthermore, because of the convolutional nature of the boundary integral and the inherent sparseness of the finite element matrix, the storage requirement is kept very low at 0(n). These unique features of the method have already been exploited in other scattering applications and have permitted the analysis of large structures with remarkable efficiency. During Phase I of the project, we will explore the method's versatility, capability, and efficiency as applied to microstrip array structures. In particular, the method will be formulated and implemented for characterizing a variety of feed structures to permit the computation of the input impedance and radiation pattern. Finally, the method's effectiveness will be examined for modelling inhomogeneous and anisotropic substrates.