A dual-band CMOS front-end with two gain modes for wireless LAN applications

A dual-band front-end with two gain modes operating at the 2.4 Industrial Scientific and Medical (ISM) band and 5.15-GHz Unlicensed National Information Infrastructure (UNII) band has been demonstrated in a 0.18-μm foundry CMOS process. The front-end uses a single set of RF blocks. A dual-band low noise amplifier (LNA) with two inputs is tuned to the two resonant frequencies by controlling the voltage on a switched resonator. The same switched resonator is also used to switch the LNA between high-gain and low-gain modes. In the 2.4-GHz high-gain mode, the front-end exhibits 39.8-dB maximum voltage gain, 1.5-dB double-side-band (DSB) noise figure, and -12.7-dBm input-referred IP₃ (IIP₃) while consuming 24 mW from a 1.8-V supply. In the 5.15-GHz high-gain mode, the front-end achieves 29.2-dB maximum voltage gain, 4.1-dB DSB noise figure and -4.1-dBm IIP₃ with 41-mW power consumption. The gains can be switched by 7 dB at 5.15 GHz and by 17 dB at 2.4 GHz.