Design of a low noise amplifier for L-band GPS applications

Abstract

The low noise amplifier (LNA) is a key part of any receiving system to prevent signal degradation due to different types of noise and the need for long transmission. This paper describes the procedures to design an LNA using a commercial SiGe hetero-junction bipolar transistor (HBT), BFP640, from Infineon Technologies. The amplifier, which satisfies certain specifications, may then be used to strengthen the L2C second civilian GPS signal. The design process was carried out using a powerful microwave CAD package, Advanced Design System (ADS), by Keysight Technologies, which provides a complete RF circuit design facility. The LNA was designed to meet the desired specifications of a low noise figure less than 1 dB, power gain of grater than 20 dB, and output voltage standing ratio (VSWR) of less than 2. The centre frequency used was 1.227 GHz, with an operating bandwidth of 40 MHz. This work thus presents a prototype model that can be readily implemented based on the calculated components of matching networks, as the simulation results demonstrate that the amplifier circuit satisfies the desired requirements.