A low-power monolithic reconfigurable direct-conversion receiver RF front-end for 802.11a/b/g applications

A low power monolithic reconfigurable direct-conversion receiver RF front-end for 802.11a/b/g applications is presented. It consists of a reconfigurable LNA and a high linearity quadrature down-converter. The LNA could be switched between two operation bands by utilizing a fully-differential switchable inductor. With a positive feedback, the noise figure of the common gate LNA is lowered down. The quadrature down-converter could be shared for multi-band multi-mode applications due to its wide band characteristics. The RF front-end has been implemented in 180 nm CMOS process and the experimental results show that the front-end could achieve a NF of 3.6 dB at 2.4 GHz and 6.6 dB at 5 GHz while providing a gain of 33 dB at 2.4 GHz and 24 dB at 5 GHz. The front-end consumes 18 mW power and the die area is 1.2 mm × 1 mm.