A WiFi and Bluetooth Low-Energy Backscatter Combo Chip With Beam Steering Capabilities

Abstract

This article introduces a dual-mode backscatter integrated circuit that supports both WiFi and Bluetooth Low Energy (BLE) transmissions. It enables a multi-antenna WiFi mode with reconfigurable beam steering of single-sideband (SSB) quadrature phase shift-keying (QPSK) signals, while also facilitating omnidirectional SSB BLE-to-BLE backscatter communication. To achieve beam steering, two techniques are proposed: 1) a transmission-line-less fully-reflective SP4T backscatter switch is employed to minimize power loss and maximize the communication range; and 2) a multi-antenna array is constructed using the aforementioned SP4T switches together with a baseband phase-shifting technique to re-radiate the incident WiFi signal with a controllable angle of direction. The chip implementation is based on a 65-nm CMOS process and operates at a power consumption of 5.5µW in standby mode. In backscattering mode, it consumes 39µW for the single-antenna approach and 88µW for the multi-antenna approach. The proposed design achieves a worst-case access point (AP)-to-AP range of 35m and 56m for the single-antenna and multi-antenna approaches, respectively.INDEX TERMS Wi-Fi, Bluetooth Low Energy (BLE), backscatter communication, Internet-of-Things (IoT), low-power wireless system, range improvement, wake-up radios.