Comparison of optimal design of different spiral inductors

Abstract

One of the key components in many RF ICs applications is the inductor. It is very important that inductor has optimal design, that means, optimal geometry with the best possible characteristics. In this work optimal design of square, octagonal, and circular spiral inductors are compared. Our optimization algorithm is based on compact model, where the physical behavior is described through analytical expressions in geometric programming (GP) form. Globally optimal trade-off curves between maximum Q-factor or self-resonance frequency and inductance are presented. Results of our software tool show that the best layout of spiral inductor is circular then octagonal and square spiral.