Electromagnetic field modeling in ICRF on the basis of standard mesh methods is complicated by different space scales of slow and fast waves. For this reason, a new method based on the approximation of solution by polynomial-exponential basic functions is proposed for advanced modeling of rapidly oscillating solutions. The method has been studied for the Helmholtz equation in comparison with standard mesh methods. The new method provides the same accuracy on a substantially rarer mesh. This advantage is more pronounced, if the solution varies very rapidly. The formalism of employment of the first-order local solution method for the boundary problem for Maxwell's equations in a slab geometry is presented. The problem of elimination of possible degeneration of the local solutions is discussed.