Design of microwave transistor amplifiers with optimum cascaded gain and noise

Abstract

The design of microwave transistor amplifiers with optimum cascade noise and gain is described. By treating two stages at a time, the condition for the second stage's noise figure needed to satisfy the total cascaded gain and noise performance is derived. Two optimal solutions are possible: Minimum cascade noise figure or maximum available cascade power gain without increasing the cascade noise over that of the minimum noise design. A design example is submitted showing the effectiveness of the proposed method in optimising the gain and noise of cascaded amplifier stages. The approach can be extended to noise temperature and multiple cascaded stages including passive blocks without any loss of generality.

A straightforward design technique for narrowband multi‐stage low‐noise amplifiers with I/O conjugate match

“…The most usual low‐noise amplifier (LNA) architecture is a cascade of common‐source stages where source inductive degeneration is very often applied . These techniques provide control on noise figure (NF), total gain, and output matching, but typically do not allow to reach an optimal condition of simultaneous input and output conjugate matching.…”