Remote and wireless sensing technology is essential for multi-parameter detection and structural health monitoring. Convention wireless systems using radiofrequency (RF) and microwave (MW)-based battery-free sensors have proven highly sensitive, cost-effective, and flexible in design for various targeted applications that involve short interrogation distances. However, these same systems are challenged with signal attenuation, interference, and limited range when deployed on large metallic structures, extended distances, or harsh environments such as high temperatures, radiation. As a result, gathering accurate, real-time data on factors such as temperature, pressure, corrosion levels or dielectric properties is complex and difficult.

NETL’s invention uses the monitored metallic structure as an electromagnetic waveguide to overcome the above-noted challenges. Rather than traveling through free space, emitted RF/MW signals are guided along the surface of the metallic conductor. Ultra-high and MW frequency radio waves from an interrogator device are sent via cableto a conical, metallic ‘launcher’ for transmission to a pipeline, exciting surface waves, which are propagated circumferentially along the length of the pipe. Alternate launcher designs may also be used. This conveys RF power to wireless, passive sensors deployed along the pipe, permitting distributed interrogation of the local environment (such as temperature, pressure, strain). The sensors submit signals back to the interrogator along the metallic surface, and data analysis of the reflected waves is then used to locate an anomaly. Subsequent processing of sensor data using advanced data analytics and machine learning tools allows for real-time monitoring and identifying problems and defects before a failure occurs.