Ultra-wideband variable gain amplifier

Ultra-wideband variable gain amplifier of radio frequency integrated circuit technology. The amplifier comprises an input stage Cascode current multiplex amplification stage, and a current mirror output buffer stage gain control stage. Cascode structure to achieve the present invention employs input matching and noise matching, while obtaining a high gain. The present invention adopts two current multiplex structure and the amplification stage output buffer stage are connected, effectively reducing the power consumption of the amplifier. The present invention employs a current mirror configuration for gain controllable gain control, while ensuring good linearity and power efficiency of the circuit.