A 750 MHz to 3 GHz tunable narrowband low-noise amplifier

An active recursive filter approach is proposed for the implementation of an inductorless, tunable LNA in CMOS. A test circuit was designed and manufactured in a 0.18 /spl mu/m CMOS technology. The feasibility of this type of LNA was demonstrated in both simulations and measurements and reasonably good performance was obtained. The measurements show a center frequency tuning range from 0.75-3 GHz and a minimum noise figure of 4.8 dB. Gain and Q value are also tunable in a wide range. Measured IIP-3 and 1-dB compression point is -24 dBm and -29.5 dBm respectively, measured at the center frequency 1.7 GHz and with 21 dB gain.