A Low-power Tunable Bandpass Amplifier for RF Applications

A bandpass amplifier with enhanced image rejection for radio frequency (RF) applications is presented. The proposed amplifier using MOS varactors and active inductors is designed for both 2.4GHz bandpass and 2.8GHz image-rejection notch filtering. With active inductors and MOS varactors, this amplifier needs no passive devices. With 2V supply voltage, the circuit exhibits gain of 20dB and image-rejection of 86dB. The tuning rang of the image frequency is from 2.8 GHz to 2.87GHz with power dissipation of 3.2mW.