It is necessary for FDTD to create a 'fit' for this material, in the same way that it must fit the Sampled data materials. It is important to understand that the analytic equation is not directly used in the simulation. The variables of the analytic model have fixed names, such as x1, x2, x3 and so on.
In this case, our function has three variables: the index of materials A and B, and the fraction of material A in the mixture. This model makes it possible to define a material via an analytic function. This type of material model can be implemented in the material database using the Analytic material model. The refractive index of this composite material is simply the weighted average a of the refractive index of the two base materials, as shown in the following formula. These two materials can be combined to produce a composite material. Suppose we have two materials: material A has a refractive index of na and material B has a refractive index of nb. This section describes the Analytic material model.
