Appendix 2: Evaluation of the integrals of potentials and field vectors due to polynomial distribution of current over bilinear surfacesThis method of evaluating the integrals should also be used if the point is close to the bilinear surface, and not only when it is on it. A similar process is used to evaluate the integrals Q,y.However, with the integrals Q,y we have additional problems. For a field point at the bilinear surface, in the general case these integrals have infinite values. In numerical evaluation of the electric and magnetic field vectors, only appropriate combinations of these integrals yield finite values which correspond to the tangential component of the electric-field vector and the normal component of the magnetic-field vector. This problem can be circumvented in several ways. The simplest is probably to position the field point close to the bilinear surface, on either side of it, instead of actually at the surface.
