STAN Circuit Stability Analysis Tool

摘要

Spurious oscillation is one of the major issues facing the designer of power amplifiers at microwave frequencies. This instability is due to the presence of feedback loops associated with high level gains even out of band. The appearance of these unwanted oscillations depends on the bias of the device (linear stability) or on the dynamic power applied at the input of the device (nonlinear stability). The possibility of obtaining information on the stability of an amplifier at the design stage is essential and even more critical for monolithic microwave integrated circuit (MMIC) technology for which adjustment after fabrication is impossible. Different methods can be used by the designers to analyze the small-signal and large-signal stability of microwave circuits. Some of these methods are implemented in commercial simulators which facilitates their utilization as μ or K factor analyses which are intended for linear two-port devices and are not suitable for multi-device circuits. More rigorous small-signal analyses, valid for multi-device circuits, have been presented in literature but these methods can be quite arduous to implement in a commercial simulator especially for circuits with a great number of active elements.