A high linearity LNA with modified resistor biasing

A 2 GHz SiGe:C HBT low noise amplifier (LNA) with improved gain compression and linearity performance is described. A modified resistor bias feed circuit for the LNA transistor improves its intermodulation and compression behavior compared to a conventional resistor bias feed circuit. Linearity enhancement is achieved by a simple feedback between the base of the current mirror transistor and the LNA transistor decreasing the low frequency bias termination. The manufactured LNA shows an IIP3 improvement of more than 6 dB and a P1dB improvement of around 4 dB compared to a conventional resistor bias feed circuit.