Load-pull Measurement Technique for 94 GHz GaAs Amplifiers based on Discrete Sampling with Compact Gamma Matching Networks

This paper presents a load-pull technique where a limited range of matching networks are synthesised on-chip to sample discrete points on the complex impedance plane. Copies of the matching networks are applied to the output of a selected transistor to enable power measurements. Data is combined together in a Focus load-pull file to allow the generation of load-pull contours. The novel technique does not use an external load-pull tuner; it utilises the excellent repeatability of multiple GaAs integrated circuit devices and an on-chip pi-attenuator for a reference load. Comparison to simulation results using a compact circuit model is promising at 94 GHz. The reflection coefficient magnitude error was less than 0.05, and the angle error was less than 1 degree with limited source power in the measurement.