Determination of a natural basis function set on thick, structured slabs using Prony´s method

The calculation of currents on a thick structured slab such as a thick slab of honeycomb is discussed. Unfortunately, for certain applications, the slab can be of the order of several wavelengths, so that the straightforward application of the method of moments using subdomain basis functions is too expensive. The authors discuss how to apply Prony´s method to the currents calculated for a thin, structured slab to obtain a natural set of basis functions to represent the currents in the interior of a thick slab. Prony´s method represents the currents as a series of complex exponential functions. The thick slab problem is then solved by the method of moments using subdomain basis functions near the slab interfaces and one or two of the complex exponentials as basis functions within the slab