N-path filter model simulation and verification at high frequencies

In this paper, a high frequency model of a N-path Band Pass Filter (BPF) is presented and analyzed for easier and faster design cycle. The analysis of N-path filters is quite difficult due to its complex operation. The simulation of such circuit must include very high number of harmonics, taking the simulation long time to converge. The N-path model allows us to reduce simulation time (up to 100 times). Usage of the improved N-path model allowed us to optimize the design and improve its performance. The ratio between the lowest and highest impedance of a N-path BPF design was improved from 15 to 33 using the model on TSMC 65nm process at Flo = 5Ghz, resulting in better rejection of the BPF.