Mechanism Analysis and Experiment of the Effects of the Guard Ring on the Inductors Performance

The grounded guard ring (GGR) is widely used to suppress the electromagnetic coupling (EMC) among adjacent inductors and reduce crosstalk with other components. However, the GGR will affect the performance of the inductor itself. To intuitively and deeply analyze the mechanism of the effects of GGR on the performance of inductors, an equivalent circuit model of inductors was adopted. Then, the substrate doping (SD) and EMC effects are introduced to characterize the mechanism of the GGR effects. To verify the correctness and rationality of the mechanism analysis, the inductors with and without GGR are taped-out using a standard 180-nm CMOS process. Then, the experimental results of the effects of GGR on the performance of inductors are presented. Furthermore, the equivalent model parameters are extracted based on measured S-parameters of two kinds of inductors. Finally, the experimental results are consistent with the mechanism analysis of the GGR effects, which has important guiding significance for the design of the subsequent GGR to improve the inductor and circuit performance.