On the point-matching method for solving electromagnetic radiation problems

Point-matching methods like boundary element method (BEM) or Nyström method have been widely applied to solve electromagnetic problems. The merits of such methods include simple mechanism of implementation, removal of basis and testing functions, and low requirement on mesh quality due to the permission of nonconforming meshes. However, the methods are primarily used to solve scattering problems so far and they are seldom employed for radiation problems yet. The main concern for radiation problems is how to apply an excitation. Unlike the method of moments with the Rao-Wilton-Glisson (RWG) basis function in which a delta-gap source can be applied over a common edge of RWG triangle, we cannot do so in the point-matching methods. In this work, we use the combined field integral equation (CFIE) as a governing equation and investigate the approach of applying an excitation in the point-matching methods. It is found that using a magnetic frill source as an excitation is a good solution as demonstrated by a typical numerical example.