Changes in dc current bias as a function of input drive for a depletion mode SiC MESFET

Power generation is an important aspect of wireless communication. The relationship between the bias current and the output power is thus of great interest. This paper describes in detail the changes that occur in the bias conditions as a function of the input drive in a depletion mode SiC MESFET device that is used in transmitters. The change in bias conditions was first noticed when measuring the output power and efficiency of the device using the load pull technique. The theory, procedure and measured results obtained from utilizing the load pull technique along with the discovery of the change in bias and an investigation of why and how the bias changes as a function of input drive is also included in this paper.