Design of 2.4 GHz LNA of 400 MHz Bandwidth

Abstract

Low Noise Amplifier (LNA) is the most important front-end block of the receiver. LNA’s Noise figure (NF) and Scattering Parameters affect the overall performance of the whole receiver circuit. Nowadays in the era of 5G technology, The quality of data that is being transmitted is increased. So there is a need for higher bandwidth to transfer data with higher speed. In such a case, communication blocks need an update. The research is carried out for the advancement of the LNA. The primary goal of LNA design is to lower the Noise Figure and return losses. The paper aims to design a 2.4 GHz LNA having a bandwidth of 400 MHz. The circuit is designed with the help of single-stub microstrip lines. We tried to keep the length of microstrip lines as minimum as possible. The transistor ATF-21170 Gallium Arsenide Field Effect Transistor (GaAs FET) is used in this work. The circuit is simulated in the Keysight Advance Design System (ADS). The amplifier is manually designed using standard methods. LNA is unconditionally stable for the frequency range of 2.2 GHz to 2.6 GHz. To build impedance matching circuits of the amplifier smith chart is used. It is observed that the LNA gain (S21) is greater than 15.3 dB, NF less than 1.2 dB, Input return loss (S11) is less than -13.3 dB, Output return loss (S22) is less than -17.1 dB over the 400 MHz bandwidth ranging from 2.2 to 2.6 GHz. This has, to the best of the authors' knowledge, not been presented in literature before.