Abstract

This paper describes the complete design methodology used to implement a MMIC lineariser in 0.25um pHemt GaAs technology. Theoretical concepts and numerical simulations of a new pre-distorter prototype designed for a wide band and high linearity power amplifier are presented. Modeling and process variations sensitivity has been accurately taken into account during the implementation of the lineariser architecture allowing a time effective and safe design approach. Several parts of the main amplifier have been reused in the pre-distorter design reducing the total development lead-time and the risk of model inaccuracies. The implemented predistortion topology has been verified using Agilent ADS simulator showing an improvement up to 10 dBc in third order intermodulation distortion (IM3) over a relative bandwidth of 28%. These results are also confirmed by experimental characterizations that demonstrate the effectiveness of the new pre-distortion scheme and implementation methodology.