Current distribution in microstrip planar antennas

Techniques are presented for the solution of two major problems encountered in attempts to solve the two-dimensional singular integral equation needed for the accurate determination of surface currents in microstrip planar antennas. The first problem in the numerical solution of the singular integral equation is the determination of a fast and accurate algorithm for evaluating its kernel, which cannot be calculated by standard computer integration methods. The second problem is the implementation of an efficient moment method, which is aggravated by the fact that the kernel is singular. The diagonal terms in the moment matrix must be carefully evaluated. The two novel numerical methods proposed are combined for the calculation of potentials.