Auburn University in Auburn, Ala., has been assigned a patent developed by four co-inventors for “reinforcement fabrics with electronic transmission capabilities.”
The inventors are three professors, Gwen Thomas, Lloyd Riggs, and David Elton, and Ph.D. graduate, Andrew Sivulka, all from Auburn.
The new fabric design includes metallic antennas and adds transmission capabilities to materials used for other purposes, such as geotextiles. When added to roadbed fabric, these antenna arrays confer the ability to transmit cellular, Wi-Fi, and other signals through the roadbed and into vehicles and surrounding buildings.
In addition to roads, these fabrics could be added to buildings, bridges, or even natural surfaces such as trees.
Source: Auburn inventors receive patent
According to Auburn’s Office of Technology Transfer, the advantages could include:
- Transmitting cellular/phone or television signals, creating internet hotspots, Wi-Fi access, and broadcast capabilities to roadways.
- Reducing the overall physical size of the antenna (or array), leading to cost savings.
- Functioning in tunnels and other areas less accessible by cellular or satellite transmissions, plus increasing area and continuity of coverage.
- Potential to enable other public safety and law-enforcement functions such as vehicle speed monitoring, vehicle tracking, traffic rerouting, and accident avoidance.
- Being less vulnerable than current systems to potential terrorist attacks, vandalism, and weather disasters, increasing the reliability and safety of the network.
This invention embodies antennas consisting of nonwoven geotextiles with embedded metallic or other wave-carrying fibers. These textiles would serve the needed purpose of the textile, such as geotextiles for road bed protection, while adding the functionality of electronic transmission.
For road applications, the geotextile and the antennas would include electromagnetic, radio signal or fiber-optic capabilities, enabling delivery of cellular, Wi-Fi, and television signals to vehicles on the road and also to nearby buildings. Transmission to nearby buildings suggests applications for this technology in “last mile” situations where other infrastructure is not yet in place.
Additionally, geotextile antennas are considerably less vulnerable to damage and are less expensive than the current infrastructure.
For work done to date, weaving or an industrial fabric method called warp-knitting is used to knit the polymer geotextile fibers with the antenna material, coupled to each other by a signal carrier. Dipole antennas are used and they are placed perpendicular to the road to achieve minimum interference.
A prototype was installed under highway pavement and tested successfully. A field test for cell phone transmission capability with antennas 50ft apart demonstrated just a -8Db loss over that distance. The signal strength of the antennas was found to be -73.3Dbm.
Elton, an Auburn civil engineering professor and current past-president of the North American Geosynthetics Society, contributed geotextile and pavement overlay expertise.
“Geotextile antennas are flexible and easily conform to natural and man-made surfaces. In particular, geotextiles used in asphalt concrete roads are especially well-protected by the asphalt pavement above, making them much less vulnerable to vandalism, terrorism, and natural disasters than conventional tower-based antennas,” Elton said.
The new antenna can be installed in high-temperature asphalt concrete pavement without damage. Beyond the use of an antenna supplying cellular phone signals, the novel geotextile can be used to deliver other services to homes and businesses including telephone, cable, Internet and electrical power through a grid under roads.
Dr. Gwen Thomas is an associate professor in Auburn’s Department of Polymer and Fiber Engineering. Dr. Lloyd Riggs is a professor in the Department of Electrical and Computer Engineering. Dr. David Elton is a professor in the university’s Department of Civil Engineering. Andrew Sivulka is an Auburn Ph.D. graduate from the Department of Electrical and Computer Engineering.