A SiGe LC-ladder low noise amplifier with base resistance match, gain and noise flatness for UWB applications

This study presents a 3.1–10.6 GHz ultra-wideband low noise amplifier (UWB LNA) in 0.18 µm SiGe HBT technology. To achieve a good input match, parasitic base resistance in a bipolar transistor and an LC-ladder filter are included into calculations with the common-emitter topology using shunt–shunt capacitive feedback. Both high and flat power gain (S21) and low and flat noise figure (NF) are achieved by adjusting the pole and zero in amplifying stage and quality factors of the fourth-order input network. Design equations for performances such as gain, noise figure and linearity IIP3 are derived especially on gain flatness and noise flatness. LNA dissipates 33 mW power and achieves S21 of 20.65+0.7 dB, NF of 2.79+0.2 dB over the band of 3.1–10.6 GHz. The simulated input third-order intermodulation point (IIP3) is −17 dBm at 10 GHz.