University of Pittsburgh and Carnegie Mellon researchers have developed a novel wireless sensing approach based on Goubau waves (electromagnetic waves on single conductors). These low loss, single line guided surface electromagnetic (EM) waves could be used to deliver wireless power to passive sensors over long distances and securely transmit collected data back to monitoring equipment.
Description
Remote and wireless sensing is key to monitoring structural health in a variety of industries including energy, aerospace, and manufacturing. Early detection of damage to pipes and other structures can ensure leaks or structural weaknesses are discovered early, avoiding catastrophic structural failure or environmental damage. However, many current sensors are not suitable for use in harsh conditions or environments. Also, growing concerns about data security, particularly in the vital utilities sector, means there is a great need to develop sensors that can accurately collect data in remote, harsh environments and securely transfer data for real-time analysis.
Applications
• CO2 Storage
• Oil and gas pipes
• Water supply pipes
Advantages
Surface acoustic wave (SAW), surface spoof plasmon (SSP), and other radio frequency identification tags are commonly used, readily available, wireless sensors. However, they have several disadvantages including a short communication range due to rapid EM attenuation in free space, making them unsuitable for use in large systems or underground structures like well-bores or pipelines. They are also unsuitable in harsh environments (e.g., high temperature or radiation). Pipes can act as circular conductors. This approach uses Goubau waves, waves that propagate on the outside of a single conductor, to interrogate distant wireless and passive sensors. Using a surface wave launcher, waves over a wide frequency range (MHzﾖGHz) could travel along a surface, with or without a dielectric coating. These waves can travel large distances compared to free space propagation and collect data from sensors to monitor structural or environmental parameters in real time with secure data transfer, overcoming the shortfalls of existing technology. Additionally, Goubau wave propagation is sensitive to dielectric properties and can detect damage to pipes.
Invention Readiness
A prototype partial cone-shaped wave launcher has been designed. Experimentation using a small-radius (0.0032 m) conductor at 435 MHz has demonstrated proof of concept. More research is required to optimize the shape of the wave launcher and examine the use of Goubau waves in conductors with larger radii as found in real-world environments.
IP Status
https://patents.google.com/patent/US20250052696A1
