Numerical Design of Non-Reciprocal Bandpass Filters With the Aid of 3D Coupling Matrix for 5G Bands

In this brief, numerical analysis on spatio-temporally modulated (STM) non-reciprocal bandpass filters is methodically demonstrated to corroborate the underlying phenomenon. The concept of a 3D coupling matrix is illustrated for the first time, which provides an analytical insight into the distribution of RF energy among the intermodulation (IM) products generated in time-modulated resonators. Flagship equations based on coupling matrix are proposed that bypass the tedious analysis of spectral admittance and ABCD matrices. These equations can be modified to design any ordered filters and with varying cross-coupling instances. The experimental validation confirms the accuracy of the numerical equations, and the model can be utilized to further the development in this burgeoning yet eccentric research domain.