Transient responses of voltage and current on ring resonator and traveling-wave loop directional filters

A time domain simulation method for analyzing the circuit operation of ring resonator and traveling-wave loop directional filters is developed. The numerical analysis model constructed with single transmission lines is based on the modified central difference method. In which the part of the coupled line is analyzed by systematic mixed even- and odd-mode model. The transient behaviors of voltage and current wave propagation all along the transmission lines are demonstrated dynamically. The results between the proposed time domain analysis and the frequency domain commercial simulator are compared, and good agreements are obtained.