Computer-aided-design techniques based on feedback concepts

Describes some novel applications of feedback concepts at microwave frequencies to linear and nonlinear active circuits yielding an improved method for assessing stability margins, a means for calculating the effects of feedback on reflection properties in linear two-ports and a powerful aid in oscillator design. The combination of the transfer function called return ratio and of simple bilinear transformations to linear systems provides designers with semigraphical tools which involve no approximations. These tools enable the amount and influence of the ever-present internal feedback on singly terminated transistors to be computed. The proposed definition of return ratio in nonlinear networks and the method of its calculation using a general nonlinear analysis program have proved to be both effective and accurate. Although the method was illustrated on a MESFET VCO it is applicable to other devices and circuits