A 1.8 dB Noise Figure 5.3-7.4 GHz BW_-3dB CMOS LNA for 802.11ax Applications

To fulfill the requirements for low noise and wide bandwidth in 802.11ax applications, a 5.3-7.4 GHz wide-band low noise amplifier (LNA) is designed. A transformer-based noise-cancellation (TBNC) technique is developed to improve the noise figure (NF) by 0.44 dB over non-cancellation designs without raising power consumption. The device incorporates a switched capacitor array for a tunable inter-stage network, offering 300 MHz sub-bandwidth and 2.1 GHz overall frequency tuning range. A wideband output matching network is also designed based on a constant-Q circle scheme. Fabricated in a 22-nm CMOS process, measurement results show the LNA achieves a 3-dB bandwidth of 2.1 GHz, a peak gain of 26.5 dB, and an NFmin of 1.8 dB. Over the operation frequency range of 5.3-7.4 GHz, the measured NF is less than 2.53 dB and the gain is better than 23.5 dB while consuming 43 mW of power.