With the increasing reliability of wireless systems, many industries are opting to replace old hardwired systems with wireless ones. Wireless systems offer lower cost, higher flexibility systems that can be deployed in some applications where wired systems would be too cumbersome. Despite the benefits of wireless systems, their deployment in industrial environments can be difficult. A high number of metal barriers such as walls, metal containers and pipes can block wireless signals from their intended paths. The curvature of these barriers present a number of challenges that affect not only the physical development of the system, but also the development of the communication schemes.

In the light of these drawbacks, the research team at Drexel has now developed a new technique of ultrasonic through metal communication system capable of transmitting data across curved barriers. Ultrasonic through metal communication systems are an effective solution for transmitting data across a metal barrier when the structural integrity of the barrier cannot be compromised by physically penetrating it. Drexel’s developed prototype system allows for ultrasonic through metal communication across the wall of a steel tube approximately 48 mm in diameter and 12 mm in thickness. Primary challenges of transducer contact, curvature effect on echoes, and alignment were addressed through the use of radial mode piezoelectric transducers, transducer "horns", and Electromagnetic Acoustic Transducers (EMATs). The developed system is very robust with negligble losses due to changes in alignment, and achieves max data rates of approximately 600kbps without echo equalization.