On Stability Analysis and Loop Oscillation of Multi-Finger GaN FET Cells for High Power Amplifiers

Abstract

Highly optimized multi-finger GaN HEMT's are prone to internal oscillations or odd-modes. Developing tools to detect and suppress these oscillations is of great help for GaN device designers. This manuscript proposes an internal oscillations detection technique based on a FET small-signal equivalent circuit coupled to Electromagnetic (EM) simulations. Then, a stability analysis technique is applied on the developed transfer function. The approach is demonstrated on three 8-finger cells using three different stability analysis techniques. All outcomes of the used stability techniques align which proves the accuracy of the developed approach.