Gain characterization of high-frequency linear-amplifier devices

Small-signal power gain measurements of active devices at high frequencies involve ambiguities due to the effects of internal feedback, making it difficult to measure accurately and isolate critical device parameters. has led to the definitioa of a new device parameter called An extensive search for a definitive gain measurement Gain Figure. Specifically: GF x (Forward Gain) x (Reverse Loss). A rigorous analysis of a two-port shows that the product of forward gain and reverse loss is equal to a particular matrix representation and is independent of the source and load admittances. Moreover, a slight extension of the analysis shows that GF is independent of y, h, and z, i.e., h and z parameters may be substituted directly and gives GF = |y₂₁/y₁₂|² = |h₂₁/h₁₂|² = |z₂₁/z₁₂|².