Performance characterisation of a microwave transistor for the maximum output power and the required noise

Abstract

The performance characterisation of a microwave transistor is carried out rigorously based on the linear circuit and noise theories, subject to the maximum output power and the predetermined input termination. For this purpose, the transducer gain G(T) is maximised analytically with respect to the input termination Z(S) for the output port matched, provided that Z(S) meets the noise figure requirement F-req >= F-min remaining within the unconditionally stable working area (USWA). Analysis is made in the z-parameter domain which facilitates a single unique crescent conditional stability configuration to replace the eight different, rather complicated stability configurations in the S-parameter domain. Finally, the compromise relations between the gain, noise figure for the output port matched are obtained with typical design configurations depending on the operation conditions of a selected high technology transistor. Incompatible noise and gain requirements can also be observed in their design configurations. Furthermore the cross-relations among the bias condition (V-DS, I-DS) and ingredients of the performance {F-req >= F-min, V-out = 1, G(T) <= G(Tmax)} triplets and together with their terminations {Z(S), Z(L) = Z*(out)(Z(S))} can be formed basis for Performance Data Sheets of microwave transistors to be employed for the amplifier designs of maximum output power and low noise.