Computational approach for resonant frequency calculation of coaxial cavity resonator using cylindrical coordinate system-based FDTD method

A computational approach for resonant frequency calculation of coaxial cavity resonator using a cylindrical coordinate system-based finite difference time domain (FDTD) method is presented. Due to the geometry shape of analyzed structure, i.e. coaxial cavity resonator, the use of FDTD method with cylindrical coordinate system is chosen instead of Cartesian coordinate system. A coaxial cavity resonator made of perfect conductor with outer diameter of 100mm, inner diameter of 40mm and length of 150mm is modeled and discretized based on FDTD notation and then numerically computed to determine its resonant frequencies in the frequency range of 1-5GHz. Moreover, a simulation using finite element method (FEM) commercialized software is also conducted to determine resonant frequencies of the resonator for comparison. From the results, it shows that the proposed FDTD approach demonstrates the capability to determine resonant frequencies of coaxial cavity resonator with an acceptable accuracy compared to the FEM commercialized software in the maximum discrepancy around than 3%.