Analysis and Equivalent-Circuit Model for CMOS On-Chip Multiple Coupled Inductors in the Millimeter-Wave Region

A growing number of on-chip inductors have been applied in the millimeter-wave IC design. The coupling effects between them have a negative impact on the performance of the circuit and each on-chip inductor. In this paper, a new equivalent-circuit model and a parameter extraction method for multiple on-chip inductors in the millimeter-wave region are proposed. The impacts of coupling effects on every onchip inductor are comprehensive considered in the proposed parameter extraction method. The characteristics of the multiple on-chip-coupled inductors are analyzed, modeled, and measured. The test structures were fabricated by 0.18-μm and 90-nm CMOS processes. The inductances, quality factors, and S-parameters of the model agree well with the measured performance of on-chip-nested and side-by-side-coupled inductors over a wide frequency range from 10 MHz up to millimeter-wave frequency band.