Simulation and implementation of a Poly methyl methacrylate based whispering gallery mode ring resonator in microwave range

This article introduces the ring resonator sensing principle and presents the simulation and fabrication of a ring resonator structure. The material Poly methyl methacrylate (PMMA) with refractive index of 1.5 has been used for fabricating it. It has low loss and thereby is a good material for constructing low loss ring resonators and generating high Q-factors. 3-D finite element numerical method (FEM) simulation results show the path of light through ring resonator and the transmission parameter of a waveguide in close proximity of a ring resonator. After coupling electromagnetic wave from the waveguide into the ring resonator, the standing waves are formed as resonant optical modes. Subsequently resonance peaks are formed in periodically repetitive frequencies in the transmission parameter of the waveguide. Transmission spectrum of waveguide has been studied in the frequency range 8–8.3 GHz. Ring resonator parameters like free spectral range and quality factor have been calculated by 0.1245 GHz and 200 respectively. Agreement and differences between simulation and experiment have been discussed.