Correct Equations for Minimum Noise Measure of a Microwave Transistor Amplifier

New equations for circles of constant noise measure in the source reflection coefficient plane are presented, and these are used to derive closed-form expressions for the minimum noise measure (
$M_{\text {min}}$
) and the associated source termination (
$\Gamma _{\text {om}}$
) for a single-stage microwave transistor amplifier. The new equation for
$M_{\text {min}}$
replaces an incorrect equation that was previously published by one of the authors. The validity of the new equations has been verified by numerical calculation, simulation, and comparison with results obtained by other authors using different methodologies.