Extraction of nonlinear Taylor series coefficients for GaN HEMT over multi-bias condition

Abstract

Taylor Series coefficients (TSCs) are one of the main factors behind the device’s nonlinearity. Multi-bias behaviour of TSCs for GaN HEMT has been extracted using two-tone technique. To extract the higher-order TSCs of the output current, two-tone intermodulation distortion (IMD) measurement along with properly designed load impedance is used at low frequency (50 and 51 ​MHz) for the accurate prediction of the cross-term derivatives. For the extraction of TSCs of the nonlinear output current, Volterra series analysis is utilized for the accurate reproduction of the harmonic component. Finally, the verification between the measured and simulated IMD products shows good agreement. This simple and straightforward method is utilized successfully for nonlinearity analysis.