On the design of broadband hybrid amplifiers using non-uniform transmission lines as impedance matching networks

Abstract

In this paper, an approach for the practical design of broadband amplifiers in hybrid technology is presented. It is based on the use of non-uniform transmission lines to implement impedance matching networks, which are synthesized exploiting the powerful optimization tools available in the most common computer-aided design software packages. The versatility of the proposed technique makes it suitable for the design of a wide variety of broadband amplifiers. Furthermore, it is easily implementable in most microwave simulators and allows a considerable design time reduction, since it can be applied in a systematic way and avoids the use of external tools. To validate the technique, it is applied to the design of a low noise amplifier using a single encapsulated transistor. A prototype was implemented, providing 10-dB flat gain from 1 to 12 GHz, noise figure under 2.5 dB, and acceptable input and output matching, which agrees with the simulation data.