A fast algorithm for calculating the reflectance of nonabsorbing multilayer dielectric films

In this paper, filtering nondesired bands of a polychromatic beam using multilayer dielectric films is described. The stop-bands could be placed anywhere in the spectrum range by carefully choosing the thickness and the refractive index of each layer. The total thickness of the structure, or the number of layers, affects the frequency response of the filter in such a way that increasing the number of coefficients of a digital filter or increasing the number of elements in an antenna array affects the respective responses. From computational point of view, reduction of computational time has been achieved by computing the characteristic matrix just once for similar layers. Illustrative examples are also given.