S-Parameter Estimation Algorithm For Coaxial Ring Resonator

The concept of the optical ring resonator has been introduced to the transmission line area for years. A resonator could be composed by a common cable and a directional coupler. Its resonance frequencies are determined by the length of cable. This paper proposed an algorithm to calculate the S-parameters and input impedance of this coaxial ring resonator. This algorithm is validated by measurements and shows good estimation accuracy. By applying this algorithm, the resonance frequencies and the features of the resonator can be quickly evaluated before the resonator is built up. It provides convenience for the engineers to choose the suitable cable and coupler without doing system measurements.