Active Device Characterization & Evaluation Using a Functional Representation of Measured Load Pull Data

This work focuses on the use of a power load pull system, driven by a CW single tone stimuli, to characterize active devices for application in linear power amplifiers. Single tone characterization data measured w.r.t. input power and supply voltage is coupled with post processing routines to predict device behavior under digitally modulated RF stimuli, such as π/4 DQPSK modulation for NADC and O-QPSK for CDMA. Additional post-processing routines estimate device potential for drain-modulated classes of RF power amplifiers, such as envelope following (EF) and envelope elimination and restoration (EER) [1,2]. Post processing of the characterization data is based on a behavioral analysis technique where the device's complex gain (G), average drain and gate supply currents are derived from single tone load pull measurements and are expressed analytically as functions of RF envelope- and supply-voltage.