Modeling of microwave ring resonators using the finite-difference time-domain method (FDTD)

Scattering parameters of microstrip ring resonators (with and without slits) that are either edge or side coupled to the feedlines are simulated by the FDTD method. The strip conductors on the device can either be infinitely thin or finite in thickness. The simulations predict the occurrence of resonance peak splitting due to the simultaneous existence of magnetic and electric field coupling mechanisms. Excellent agreement was obtained between the simulation results and the measured data for a ring resonator. We have also shown that it is possible to use finite-difference time-domain simulations to determine the dielectric constant of substrate materials.