CMOS-Based Active Tunable Radio Frequency Filter

A RF tunable active bandpass filter with active inductor using Q-enhancement circuit is presented. The RF active filter was implemented by the TSMC 0.35 ¿m 3P3M BiCMOS process. In order to improve the quality factor of the active inductor, the Q-enhancement circuit was used to compensate the loss of the active inductor. The insertion loss of the RF tunable active filter is about 0.5 dB, and the tuning range of center frequency is from 725 MHz to 2050 MHz.