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.