Increasing the bandwidth of a SiGe HBT LNA with minimum impact on noise figure

This paper introduces a matching technique for highly sensitive integrated broadband low-noise amplifiers. Noise matching is achieved by the paralleling of identical input transistors. Impedance matching, based on reducing the number of components to the absolute minimum, is done by using the base-collector capacitance as network element. Using a 0.13 μ m silicon-germanium (SiGe) bipolar complementary metal oxide semiconductor process, simulation results indicate a maximum noise figure of 0.462 dB at room temperature and a return loss better than 10 dB from 300 MHz to 1.4 GHz. The technique demonstrates that SiGe heterojunction bipolar transistors can be used for cost-effective applications in radio astronomy.