Moment method solution using expansion functions defined in an infinite-domain

The efficiency of the moment method when the expansion functions are defined in an infinite domain is checked. It is shown that an efficient solution is obtained when the expansion functions obey the known physical behavior of the fields. The age-old problem of the thin, charged disk is solved by the moment method for which the electric field is expanded outside the body. Excellent agreement between the analytical solution and the moment method solution was achieved.