Linear, Quasi-Linear and Nonlinear Microstrip Oscillator Designs

Abstract

In this paper the analysis and design approaches of microwave oscillators are surveyed and classified into three categories namely, linear, quasi-linear, and nonlinear. An applicable method is chosen from each approach to be implemented using MATLAB package. These MATLAB written programs are used to design an 8.5 GHz microstrip oscillator. The results of these programs are entered to a powerful CAE package, namely the "Microwave Design System", as initial designs. These designs are enhanced using the available optimization routines. The final optimized linear, quasi-linear, and nonlinear designs are compared using the most powerful nonlinear simulation and the transistor nonlinear model. From these simulations, the performance of each design method can be determined accurately. It is found that the nonlinearly designed oscillator circuit is the most accurate one. This circuit is fabricated and measured to verify the validity of the used simulation techniques. Excellent agreement between theoretical and experimental results is obtained.