Abstract

This paper emphasizes for the first time the link existing between some small-signal power gain circles and the output load of maximum power in GaAs HBTs. We use the locus of power gain, named Minimum Conjugate- Termination Power, which have the value MSG/2K. MSG is maximum stable gain and K the stability factor. This method has been applied to the measurements by load-pull of 30W S-Band HBT power bar. By varying the bias of the amplifier, it is possible using only S-parameters data to localize accurately and quickly the locus of the power load.