Conservative current and charge data extracted from pulsed S-parameter measurements for GaN HEMT PA design

Power Amplifiers can either be designed directly from load-pull data or using CAD software with embedded nonlinear models. Both approaches have advantages and disadvantages and their own range of applicability. Availability of reliable transistor models is usually the main factor to decide which approach to be followed. This paper presents a double pulse S-parameter measurement system that enables the extraction of current and charge conservative models of GaN HEMT devices. The obtained characteristics were used to predict the transistor load-pull curves which finally led to a RF power amplifier design. The very good agreement obtained between the output power and efficiency load-pull predictions, and their corresponding PA measured values, attest the quality of the extracted current and charge data, using the developed system.