Distributed Characterization of On-Chip Spiral Inductors for Millimeter- Wave Frequencies

Abstract

This paper presents a new scalable 2-π equivalent circuit model of on-chip spiral inductors. The model characterizes on-chip inductors of variable geometrical sizes and number of turns. The density distribution of the magnetic and electric field effect in the metal traces forms the bases for lumped circuit element characterization of the inductor parasitic. The study, therefore, uses the RLC network algorithm to compute a new equation for predicting the self-resonance frequency of on-chip inductors. Inductance, quality factor, and S-parameter plots are shown as the results of the different turns and sizes. The verification of the model illustrates good agreement with the measurement data up to 40GHz. Hence the root-mean-square error of the quality factor of the model with the measured data is 0.0332. The model further demonstrates sufficient reliability to predict the performance of the on-chip inductors in simple RFIC design.