Design of GaAs MESFET Oscillator Using Large Signal S-Parameters

A design method of GaAs MESFET oscillator using large signal S-parameters has been discussed. Together with the measurement results of the dependence of large signal S-parameters on power level and bias condition, computer analysis of the equivalent circuit for MESFET´s has qualitatively clarified the large signal properties of MESFET´S. On the basis of these S-parameters has been designed the MESFET oscillator over the frequency range of 6-10 GHz, which has resulted in power output of 45 mW at 10 GHz with 19% efficiency and 350 mW at 6.5 GHz with 26% efficiency respectively. Good agreements between predicted and obtained performance of MIC positive feedback oscillator have been ascertained, verifying the validity of the design method using large signal S-parameters.