RF spiral planar inductor designs - preliminary results [RFIC applications]

Inductors that can be integrated on a silicon chip have been reported in the literature. This has lead to the development of silicon RF integrated circuits (RFICs) where previously discrete component inductors had to be used. Now the size of circuits can be greatly reduced with the integration of RF circuits or even complete systems on a silicon chip. This has raised enormous interest in the study of the on-chip inductor. This paper presents a comparison of various inductor expressions available in the literature. Error trends are highlighted and discussed in the 1 to 10 nH inductance region. The focus of the design is the square spiral inductor. The details of the ´new-physic´ closed-form expression is found to be the most accurate expression and its implication to inductor synthesis is discussed.