RF-Powered Low-Energy Sensor Nodes for Predictive Maintenance in Electromagnetically Harsh Industrial Environments

Area of Science:

• Wireless Sensor Networks
• Electromagnetics
• Energy Harvesting

Background:

• Metal-rich, electromagnetically harsh environments pose challenges for traditional sensor networks.
• Periodic battery replacement is costly and impractical for remote or inaccessible sensor nodes.
• Existing wireless power transfer systems struggle in non-line-of-sight (NLOS) conditions.

Purpose of the Study:

• To design, implement, and validate a wireless sensor network (WSN) for predictive maintenance and remote monitoring.
• To enable battery-free operation of sensor nodes in challenging environments using wireless power transfer.
• To demonstrate the feasibility of powering sensors in non-line-of-sight (NLOS) positions.

Main Methods:

• Development of a wireless power transfer system using three co-located active antennas operating at 2.45 GHz.
• Design of compact, low-power, robust sensor nodes with conformal antennas for NLOS energy reception.
• Conducting a measurement campaign in a car engine compartment to simulate real-world automotive applications.

Main Results:

• A radio-frequency (RF) source with 27 dBm EIRP can fully charge a sensor node (4.8 mJ) in under 170 seconds at a 112-cm NLOS distance.
• Transferred power enables sensor node operation every 60 seconds, including data sampling, processing, and Long Range (LoRa) communication.
• Active cycle energy requirement is 1.45–1.65 mJ, with sleep mode current < 150 nA, achieving up to 1.7% duty cycle for battery-free operation.

Conclusions:

• The developed wireless power transfer system effectively powers sensor nodes in harsh, NLOS environments.
• Battery-free operation is achievable for predictive maintenance and remote monitoring in the automotive sector.
• The system offers a robust and sustainable solution for sensor networks in challenging industrial applications.