Equivalent load impedance

Two-port networks are normally used for oscillator or feedback amplifier synthesis by aggregation in four possible configurations. To define the oscillation frequency or stability margins a return ratio should be used. A technique is developed to define the analytic relation for the return ratio of an oscillator in frequency domain. Its application requires the knowledge of the equivalent load impedance. A special case is also discussed when the return ratio definition is significantly simplified. Presented simulation results demonstrate the application of the equivalent load impedance calculation technique for oscillator synthesis.