A Current Chopper-Assisted Magnetic Field-Based Backscatter Communication Method With WPT Overcoming Ultralow Coupling Coefficients

This article proposes a magnetic-field-based backscatter communication method that enables ultralow-power wireless communication. In this approach, a client node extracts energy from a magnetic field for wireless power transfer (WPT) and backscatters it while embedding information. The client node modulates the magnetic field for WPT by chopper-controlling the current in its power-receiver coil, eliminating the need for power-hungry oscillators. As a result, communication is achieved using only the energy required to drive the gate of a MOSFET, leading to significant power savings. Experimental validation with a prototyped system demonstrated a receivable power of 1.52 mW, a 38% increase over existing chopper-based methods, at a distance of 50 cm. In addition, simulations using a TSMC 180-nm process revealed that communication energy can be reduced to 0.36 pJ/bit, achieving more than a 90% reduction compared with conventional approaches. These results confirm that the proposed method greatly enhances energy efficiency, making it suitable for submeter-range, low-power wireless communication in embedded sensor applications, such as infrastructure monitoring.