Characterisation of L-band differential low noise amplifiers

[摘要] ENGLISH ABSTRACT: This thesis addresses the complications that are encountered when characterising the performance of differentialmicrowave LNAs. The predominant sources of noise in electronic circuits are introduced and equivalenttwo-port noise models for active devices are derived. Correlation between noise generators are defined bymeans of the noise correlation matrix and existing network theory is adapted to include noise analysis of twoportand multi-port networks. Mixed-mode scattering parameters are introduced in order to define the signalperformance of differential and common-mode propagation in multi-port networks and, by applying the sametheory, the mixed-mode correlation matrix for a three-port dLNA is derived. Furthermore, an expression is derivedfor de-embedding the differential noise figure of a three-port dLNA using two single ended measurements.Two dLNA designs, both incorporating wideband 180°-Hybrid ring couplers, are discussed and the differentialsignal and noise performance of the dLNAs are compared to that of their constituent single ended LNAs.

[发布机构] Stellenbosch University