Local demagnetizing tensor calculation for arbitrary non-ellipsoidal bodies

The distribution of the magnetization in planar ferrite devices is nonuniform due to the nonuniformity of the demagnetizing field. A method for calculating the local demagnetizing tensor for arbitrary 3-dimensional shapes, using the Finite Difference Method (FDM), is developed. The sample is discretized into rectangular elements and the magnetostatic interaction between each pair of elements is computed. The local demagnetizing tensor is obtained as the superposition of all interactions at the given element. With proper boundary conditions the method can be applied to the computation of the local demagnetizing tensor for arbitrarily shaped bodies. The local demagnetizing tensor can be used to calculate the non-uniform distribution in the ferrite, and to optimize the shape and size of the ferrite in the CAD of microwave devices.