Multi-Antenna Directional Backscatter Tags

A directional backscatter tag is proposed to enhance the range of backscattering communications. The tag uses multiple antennas acting as a reflectarray by configuring constant phase gradients depending on the direction of arrival (DoA) of the signal. The DoA is determined using RSSI measurements across different tag reflection configuration. As a proof of concept, a directional backscatter tag using a 3×3 antenna array is implemented. It provides a 19dB sensitivity enhancement resulting in an up to 3× increase in range compared to backscatter communications with a single antenna tag.