Design and Fabrication of a 1.5GHz Microwave Low Noise Amplifier with Suitable Low-noise and High Gain Characteristics

This paper presents the design, simulation and fabrication of a low noise amplifier with high gain of 1.5GHz. In communication systems, there is always difficulty in distinguishing the received signal from noise at very low signal powers. A low noise amplifier (LNA) is an effective and low-cost way of enhancing this signal quality through signal amplification at the receiver. In this work, LNA simulation and a novel design was carried out using the N76038A field effect transistor (FET). To ensure it is stable over a wide range of frequencies, the input and output stability of the transistor were plotted over its operating frequencies (0.1 GHz to 18 GHz). Constant gain and noise figure circles were plotted and the source impedance properly chosen. The input network was matched to the source impedance and conjugate matching used to match the output. The schematic was converted to microstrip and produced on a printed circuit board. Testing was carried out using the vector network analyser (VNA) and matching errors then corrected by calibration process. The fabricated LNA has a gain of 13.76dB and noise figure of 1.57dB which is in close agreement with a simulation result of 14.25dB and 1.56dB respectively.