Low loss integrated N-path-filter-based circulator

In this paper, the integrated N-Path-Filter-Based circulator is thoroughly analyzed. Simplified linear time invariant (LTI) circuit models are introduced in order to perform the analysis. These models are then verified by comparison to the complex linear periodic time varying (LPTV) model of the circulator. Exploiting the insight acquired from the simplified models, a new and improved topology for the integrated circulator is proposed. The simulated sum of Tx-to-Ant insertion losses and NF are less than 1dB at 100MHz and less than 2dB at 2GHz. These results are significantly better than the previously reported state-of-the-art integrated circulator.