Frequency response enhancement of spiral inductor's Q-factor by adopting defected ground structure in standard CMOS process

In this paper, a planar spiral inductor with defected ground structure is proposed. The single-π model is established. Equations of the self-resonate frequency and the frequency with maximum quality factor are obtained, in which explanations and approximate solutions are given. The proposed inductors were fabricated in 65nm CMOS technology. Measured results match well with simulations and models up to 75GHz. Compared with traditional inductors, the proposed inductor can improve the frequency with maximum quality factor from 16GHz to 34GHz and 27GHz to 55GHz, respectively, while achieving good flatness of quality factor within broadband millimeter-wave range. The measured maximum quality factor is around 12.