FDTD Modeling of Time-Modulated Resonators-Based Bandpass Filters using Modified Telegrapher's Equations

This manuscript reports for the first time on a new finite-difference time-domain (FDTD) modeling technique for non-reciprocal bandpass filters (BPFs). The proposed approach is based on modified Telegrapher's equations that are adjusted to facilitate the FDTD modeling of discrete time-invariant and time-variant L, C components, and LC resonators that can be used for the design of RF components. In this paper, this method has been exploited for the design of non-reciprocal BPFs using time-variant resonators. The efficacy of the approach is demonstrated through the modeling of two non-reciprocal filtering examples that are compared with harmonic balance simulations in Keysight ADS. These include a three-pole BPF and a three-pole/two-transmission zero (TZ) non-reciprocal BPF.