Metasurfaces for Polarization-Insensitive and Directional Backscatter Communications

Achieving low-power and polarization-insensitive communication is a crucial and challenging task in the Internet of Everything. In this communication, we propose and demonstrate the implementation of two amplitude-reconfigurable metasurfaces, loaded with p-i-n diodes and operated around 5.8 GHz, to develop a novel polarization-insensitive backscatter communication (BC) system. Both communication transmitters using uniform and gradient metasurfaces are able to achieve high-efficiency polarization conversion and thus can cooperate with the receiver end to mitigate the interference generated by environmental carrier sources. To achieve the directional information transmission, we design a corner reflector metasurface and a gradient metasurface, which, respectively, enhances the gain in the backward and fixed scattering directions. Due to the advantages of polarization insensitivity and low energy consumption, this system promises great potential for future engineering applications in the Internet of Things, particularly for smart homes, wearable sensing, and other related areas.

I. Introduction

In recent years, backscatter communication (BC) has attracted a lot of attention [1], [2], [3], [4]. BC systems usually use the electromagnetic signals already existing in the environment as the carrier source and modulate the sensor information into the backscatter signals. The communication power consumption is reduced to the microwatt level by eliminating the need for a carrier source, avoiding the utilization of an oscillator, power amplifier, and other high-power components typically found in the conventional communication systems. In 2013, Smith’s research group at Washington University initially proposed the concept of environmental BC and successfully demonstrated intercommunication between two passive devices [1].