Parameter Extraction and Optimal Design of Spiral Inductor Using Evolution Strategy and Sensitivity

Abstract

For precise electromagnetic (EM) field simulation of the spiral inductor, electric conductivity of the inductor substrate is determined by evolution strategy to match the Taiwan Semiconductor Manufacturing Company (TSMC) process. Based on this parameter, patterned ground shield (PGS) of an on-chip spiral inductor is designed using deterministic optimization method. The design parameters are lengths and widths of ground strips and widths of slots. For sensitivity analysis, approximate adjoint variable method is used. Significant increase in Q-factor is observed in final design while reduction of inductance is minimal. Spiral inductor with optimized PGS is used in input matching circuit of 2.45-GHz low noise amplifier (LNA), which shows improved noise figure characteristics compared to non-PGS case.