Design of An Optimal Low Noise Amplifier (LNA) for Signal Boosting

Abstract

The purpose of a Low Noise Amplifier (LNA) is to amplify received signals to acceptable levels while minimizing noise. The LNA is used in communication systems to amplify very weak signals captured by an antenna. The design of an LNA in Microwave circuits requires a trade-off or careful balance of many important parameters such as Gain, Noise Figure (NF), and Stability. In view of this, it is essential to make calculated choices to realize an optimally functioning LNA. This paper presents a single stage 2.0 GHz LNA optimal design using lumped elements (discrete passive components) for the input and output matching networks. The Radio Frequency (RF) transistor used for this design is the ATF-21170, which is modelled by its Scattering (S) parameters. This is a high performance, low noise Gallium Arsenide Schottky barrier-gate Field Effect Transistor. The LNA is designed using conventional techniques to boost weak cell signals in the frequency range of 1.8GHz to 2.6GHz. The design is done with the aid of Advanced Design System (ADS) 2020 software. The LNA was successfully designed at an operating frequency of 2.0GHz with a gain of 14dB and a minimum noise figure (NFmin) of 0.83dB.