A 2.4-GHz, Hybrid 10-Mb/s BPSK Backscatter and 1-Mb/s FSK Bluetooth TX With Hardware Reuse

This letter presents a hybrid architecture for wireless transmitters that reuses the same hardware and antenna to selectively operate in either backscatter or conventional modes, with a minimum of added complexity. A single FET stage is used as both a Class-C power amplifier for a conventional 2.4-GHz, 1-Mb/s frequency shift keying Bluetooth low energy (BLE) transmitter with peak efficiency η ≈ 78%, as well as a 10-Mb/s BPSK modulator in an ultralow power backscatter mode. A transmitter energy consumption of 81 nJ/b at an output power level of +14 dBm is achieved in the 1-Mb/s conventional mode, while only 32 pJ/b is required in the 10-Mb/s BPSK backscatter mode. It is shown that the data rate of the backscatter mode can be decoupled from the conventional mode, such that the backscatter link can operate at ten times the rate of the conventional link, while achieving over three orders of magnitude power savings. This approach is equally applicable to other communication standards, such as Wi-Fi (IEEE 802.11b), Zigbee (IEEE 802.15.4), and so on.