A Reconfigurable SWIPT Antenna Array for Battery-Assisted Cooperative Relaying in IoT Networks

Cooperative relaying (CoR) is extensively utilized to extend the communication range, spectral efficiency, and system capacity. To achieve a highly reliable and sustainable CoR, the antenna system at energy-constrained relay nodes should provide broader coverage with the capability to replenish its battery. This work proposes a 2×2 reconfigurable simultaneous wireless information and power transmission (SWIPT) antenna array comprising four frequency-splitting antenna elements. A reconfigurable feed network is designed to achieve pattern and polarization reconfigurable wireless information transmission (WIT) in 5 GHz WiFi band. On the other hand, WPT is implemented at 5 GHz utilizing a completely integrated conjugate impedance-matched full wave rectification circuit. Moreover, the DC outputs of all four SWIPT antenna elements are combined in parallel to enhance the overall harvested DC power with negligible circuit losses. The performance of the proposed antenna system is validated using software-defined radio to showcase its capability to implement battery-assisted cooperative relaying in IoT networks.