Theory of scalar wave propagation in periodic composites: A k·p approach

A simple, yet accurate, band structure formalism is presented to describe dispersion relations of scalar waves in periodic composite structures. We develop a scalar wave version of k·p theory, a technique which has been successfully used for calculating electronic band structures in semiconductors. The formalism permits easy description of the band structure around some interesting points in k-space without intensive computation. The accuracy of the method is demonstrated by considering numerical examples for the case of a square array of dielectric cylinders embedded in a host medium.