A simplified approach to optimum noise source impedance determination for GaAs FET amplifiers

A simplified, analytical approach to determine the optimum noise source impedance of a GaAs FET amplifier is developed. The approach requires a knowledge of the transistor's small-signal model parameters and its minimum noise temperature versus frequency. The approach described is currently limited to the UHF and VHF bands. The amount of error in the computed value of optimum noise source impedance is proportional to the error in the minimum noise temperature data when the error at each data point is correlated. When the error is uncorrelated, the method does not yield acceptable results. Numerical results and an error analysis are presented.<
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