Dual bias feed SiGe HBT low noise linear amplifier

A 2 GHz-band SiGe HBT low noise amplifier (LNA) achieving high saturation power and low distortion performance is described. It has a novel diode/resistor dual bias feed circuit for the base of the HBT to extend its P1 dB. In the small signal region, the conventional resistor feed circuit is a dominant base current source, but the in large signal region, the diode turns on and the diode feed circuit can supply base current like a voltage source which allows higher output power and linearity. The fabricated dual feed type LNA shows the P1 dB improvement of 5 dB compared with the conventional resistor feed LNA.