A Direct-Conversion CMOS RF Receiver Reconfigurable From 2 to 6 GHz

A CMOS direct-conversion receiver with only one signal path is reconfigurable from 2 to 6 GHz in the RF band and from 3.6 to 54 MHz in the channel bandwidth. By employing a voltage feedback in a common-gate low-noise amplifier (LNA), the input matching of the LNA can be reconfigured for each RF band by simply changing the resonant frequency of the load network. The frequency characteristics of the active-RC channel selection filter with an R-2R ladder is automatically tuned by a one-shot tuning circuit. Implemented in 0.18-mu m RF CMOS technology, the whole receive path shows 4.6-5.6-dB noise figure while consuming 65-75 mA from a 1.8-V supply depending on the mode of operation.Manuscript received October 20, 2009; revised May 03, 2010; accepted June 02, 2010. Date of publication August 09, 2010; date of current version September 10, 2010. This work was supported by the Research Fund of Hanyang University (HY-2007-S) and by the Center for Advanced Transceiver Systems (CATS)