Design and analysis of spiral circular inductors for GaN based low noise amplifier (MMICs)

This paper presents a novel approach for the design, analysis and optimization of spiral circular inductors to be fabricated on Silicon Carbide (SiC) substrate of thickness 100μm. These inductors are designed for use in Gallium Nitride (GaN) based Monolithic Microwave Integrated Circuits (MMICs) specifically for low noise amplifier circuits. On basis of the maximum figure of merit indicator FMI (Q × SRF/chip area) inductors of various strip-widths (μm) i.e. for 12, 16, 24 and 36 from 1 to 5 turns steps of 0.5 turns have been simulated using ADS (Advanced Design System) software. The maximum simulated Q-factor is 54 at 22 GHz and SRF is 46 GHz for 1-turn inductor of 12μm width with maximum figure of merit. The Q-factor is 23 at 2.8 GHz and SRF is 5.6 GHz for 5-turn inductor of strip-width 12μm. The inductance values vary from 0.46 nH for 1-turn to 5.6 nH for 5-turn inductor of strip-width 12μm.