An 802.11b-WiFi Backscatter Modulator Featuring 30 dB PSLR with All-Digital Gaussian Pulse Shaping

Conventional WiFi transceivers consume 10s to 100s of milliwatts of power, which necessitates large batteries and limits large-scale IoT deployments. WiFi backscatter systems can reduce power consumption to 10s of microwatts, enabling operation from small batteries or energy harvesting, and thus making large-scale deployment feasible. However, conventional ambient WiFi-to-WiFi and Tone-/BLE-to-WiFi backscatter systems directly modulate the carrier with rectangular baseband signals, resulting in excessive spectral occupation and interference with other wireless technologies operating in the 2.4-GHz ISM band. This paper addresses this challenge by proposing a pulse-shaped, frequency-translating 802.11b-WiFi backscatter modulator employing an all-digital Gaussian filter. The proposed modulator achieves a PSLR of 30 dB, representing a 17 dB improvement over conventional WiFi backscatter modulators, and an EVM of 13.2%–15.5% at 11 Mb/s, while consuming 19 µW of power. The generated WiFi packets can also be directly received by WiFi APs.