Characterization and Modeling of Multiple Coupled Inductors Based on On-Chip Four-Port Measurement

Because of the compact layout of RFICs and mm-wave ICs, coupling effects among neighboring inductors may seriously degrade circuit performance. This paper analyzes the coupling effects among multiple on-chip spiral inductors and develops a fully scalable compact lumped element model for multiple coupled inductors by using four-port S-parameters. Each single inductor model is directly extracted from four-port S-parameters based on a one-port extraction algorithm. Mutual inductance and coupling capacitance among inductors is extracted and added to the single inductor models. Compared with the measurement, the proposed model can accurately predict the physical behavior of multiple coupled inductors from dc to self-resonant frequencies, as well as EM simulation results. The test structures were fabricated in a commercial 0.18 μm RFCMOS process.