Deterministic design of simultaneously matched, two-stage low-noise amplifiers

This contribution presents a novel, deterministic design technique of two-stage low-noise amplifiers amenable to EDA implementation. The proposed method, which is based on the concept of noise measure and on the theoretical bounds to input/output matching of active devices, adopts inductive source degeneration to automatically produce a set of two-stage designs featured at nominal frequency by a given gain, perfect matching at both sections and almost optimum noise figure. Then, based on overall performance over frequency, the designer can choose the best performing solution from the set, avoiding the tedious, time-consuming trial-and-error of traditional approaches. The technique is demonstrated by designing a Ka-band two-stage LNA on a commercial GaAs HEMT technology provided by OMMIC. Simulated performance comprises a gain of 17 dB and a 1-dB noise figure. A measurement campaign is going to start soon on the fabricated LNAs, which have only recently become available to the Authors.