Frequency responses of circular spiral inductors for GaAs RF MMIC applications

The aim of this paper was to investigate the characteristics of inductors fabricated using GaAs microwave monolithic integrated circuits processes. We fabricated and measured over one hundred different spiral inductors, changing their layout parameters. The S-parameter optimization was used to estimate the lumped elements of the pi-equivalent circuit model of the inductors. The important effects of the layout parameters on the quality factor and the insertion loss are presented. The series resistance increased linearly with increasing number of turns, but no remarkable effects of the diameter on the resistance were observed. The inductance increased abruptly with the number of turns, and showed an increasing linear dependence on the diameter. The effects of metal line width and spacing on the frequency responses of the inductors are described.