Tech Briefs

Fiber antennas can be directly incorporated into fabrics.

Soldiers performing dismounted operations in the field use radios that have antennas with a distinct visible signature and can become easy targets. These antennas also tend to snag on other equipment or vegetation, creating a hazard and a distraction to any ongoing operation. Therefore, it has become necessary to develop an antenna that can conform to soldiers and be virtually indistinguishable from a soldier’s body armor.

The Patch Antenna (red box) is shown attached to the shoulder of an Army-issued jacket using a hook-and-loop connector. The antenna can be connected to a radio with a cable running down the back.
Traditional antenna materials such as metals tend to break under repeated cycles of loading and unloading, which makes them undesirable for this application. Existing wearable antenna technologies have limited bend radii, are bulky, and cannot easily be incorporated into clothing.

This innovation uses conducting polymer materials to create patch antennas that can easily conform to a soldier’s body and can match the performance of existing antennas. Antennas based on these materials have reached high enough electrical conductivities such that they have been developed for radio frequency identification (RFID) applications. These materials can be developed as flexible, conformable, and even transparent alternatives to traditional metal-based approaches.

Conducting polymers are electrically conducting materials that have high electrical conductivities (~105 S/m) and are extremely lightweight and flexible. Wires synthesized from these materials have a wide range of applications that can include smart textiles, neural probes, polymer-based actuators, sensors, and antennas. The fabrication technique involves an additive printing technique that can print numerous patterns, but with limited inherent conductivity (less than 600 S/m). There is also interest in generating highly electrically conductive polymer fibers that can be directly incorporated into clothing to function as an antenna, but a printing technique has to be developed for this process.