Designing FET's for broad noise circles

It is shown that the keys to broader noise circles are a lower minimum noise figure and a small optimum generator reflector coefficient. An optimum FET width for the smallest generator reflection coefficient and the broadest noise circles has been demonstrated with 0.25 mu m MODFETs. A FET of optimum width also has the lowest noise figure with a 50 Omega generator. An expression is derived showing that the optimum gate width is inversely proportional to frequency, and that the optimum width should be a weak function of gate length for FETs optimally scaled for gate length.<
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