A Low-Power Interference-Tolerance Wideband Receiver for 802.11af/ah Long-Range Wi-Fi With Post-LNA Active $N$ -Path Filter

A low-power interference-tolerance wideband receiver with post-LNA active N-path filter for RF channel selection is proposed for 802.1af/ah long-range Wi-Fi standards. By leveraging gain, noise, and filtering characteristics among the wideband LNA, high-Q active N-path filter, and reconfigurable analog baseband circuits, the proposed receiver achieves high gain, low noise, and high linearity with low power dissipation. The receiver provides narrow-bandwidth RF filtering with a small chip area. Implemented in a 40-nm CMOS process with the chip size of 1.1 mm x 2.25 mm, the full receiver shows a conversion gain of 84 ± 1 dB and achieves noise figure from 3.4 to 3.9 dB in subgigahertz frequency bands. The measured in-band IIP3, out-of-band IIP3, and out-of-band IIP2 are -5.9, -0.5, and +62.5 dBm, respectively. The proposed receiver dissipates an average power of 41 mW.