Design and Test of an L-Band (GNSS) Low Noise Amplifier and Limiter

Abstract: Abstract This thesis work was performed at RUAG Space AB, Göteborg, Sweden. The aim of this thesis is to test the performance boundaries of SiGe based heterojunction bipolar transistor in designing a low noise amplifier meant for GNSS applications. After careful consideration of different alternatives for active components in SiGe HBT process, BFY640-04 from Infineon was selected as the active component for the design. Later, different topologies have been evaluated in Advanced Design System (ADS) software and finally a common emitter topology is selected considering cost-effectiveness, performance and simplicity. Apart from this, the functionality of a limiter component namely, GG-77015-01 from Microsemi has been tested by placing it in front of the LNA. The purpose of this is to know if it can prevent the LNA from high power levels and to study its overall effect on noise figure, gain and linearity. The prototypes were fabricated on a hardback PCB consisting of Roger Duroid 6002 substrate. The designed LNA has less than 1 dB (excluding limiter) noise figure, gain of 17-13 dB and input return loss of 6 dB. It is powered by a single positive supply of +5 V and has very low DC power consumption of 15 mW. Also, the noise figure is fairly low in the entire L-band apart from current GNSS bands, which provides possibility of this design to be useful in future GNSS applications too.