Resonant frequency calculation for inhomogeneous dielectric resonators using volume integral equations and face‐centered node points

The face‐centered node‐point technique, developed earlier for scattering applications, is applied to the calculation of resonance frequencies of inhomogeneous dielectric resonators. The described method leads to a well‐conditioned matrix system suitable for numerical solution, which is not the case when the permittivity is high and conventional solution techniques (e.g., pulse functions with cell‐centered point matching) are employed. In this work, we concentrate on resonators having the shape of a parallelepiped, for which there are relatively few computational results in the literature, although the method can accommodate arbitrarily shaped structures.