An RF bandpass filter with a Q-enhancement active inductor is presented. The design technique for a tunable Q-enhancement CMOS active inductor operating in the wide RF-band is described. Moreover,issues related to noise and stability of the active inductor are explained. The filter was fabricated in 0.18μm CMOS technolo- gy,and the circuit occupied an active area of only 150μm ×200μm. Measurement results show that the filter centered at 2. 44GHz with about 60MHz bandwidth （3dB） is tunable in center frequency from about 2.07 to 2. 44GHz. The ldB compression point is - 15dBm while consuming 10. 8mW of DC power,and a maximum quality factor of 103 is attained at the center frequency of 2.07GHz.
