A Low-Power 2.4-GHz Receiver Front End With a Lateral Current-Reusing Technique

A 2.4-GHz current-reused receiver front end is presented in this brief. Instead of using the traditional stack-on current-reusing scheme that compresses the voltage headroom, the proposed front end employs a lateral current-shunt branch to share most of the dc bias current of the transconductance transistors in an LNA and a mixer. To prevent the signal interaction between the two modules, an LC tank is inserted into the current-reusing path to cut off the radio-frequency signal path between the LNA and the mixer. The IF signal blocking is realized by inserting a cascode transistor that provides large impedance for the IF signal from the mixer. Theory analysis and simulation results indicate that the current-reusing structure improves the noise performance and only a small impact on the voltage gain. A prototype of the proposed front end is designed and fabricated in the 130-nm CMOS process. Measurement results indicate that the front end achieved a conversion gain of 25 dB, a double-sideband noise figure of 3.5 dB, and a third-order input intercept point (IIP3) of -13 dBm at an input frequency of 2.4 GHz. The dc consumption of the front end is 3 mA under a supply voltage of 1.2 V.