Imagine a lightweight sweater or blanket that doubles as a powerful radio-frequency antenna.
Engineers at Columbia University have achieved this remarkable feat by combining advanced engineering with an old-school knitting technique.
Their work could revolutionize how antennas are made and used, offering a lightweight, portable alternative to the heavy, rigid satellite antennas we use today.
Why knit an antenna?
Traditional antennas, especially the highly directional ones used in satellite communication, are bulky, rigid, and expensive to manufacture.
While these conventional designs excel in performance, they are not practical for applications that require portability or flexibility, such as wearable tech or satellite missions.
To overcome these challenges, researchers have been exploring ways to create smaller, flexible antennas using textiles.
However, previous methods, like printing or embroidering conductive materials onto fabric, have often resulted in issues such as cracking, peeling, and limited scalability.
The Columbia team decided to take a fresh approach: integrating antennas directly into textiles during the knitting process.
The team, led by Nanfang Yu, an expert in metasurfaces (ultra-thin optical components), turned to an old knitting method called float-jacquard knitting.
This technique, commonly used to make patterned sweaters, involves using two or more yarns to create intricate designs.
When a yarn is not needed for a specific part of the pattern, it is “floated” underneath the fabric and brought back to the surface when required.
Using commercially available metallic and dielectric yarns, the researchers applied this technique to knit prototype antennas, called metasurfaces.
These lightweight, flexible antennas are built into the fabric itself, eliminating many of the problems associated with other methods. This innovative process allows antennas to be made quickly, affordably, and on a large scale using existing industrial knitting machines.
The team developed two types of prototype antennas: a metalens and a vortex-beam generating device.
The metalens shapes radio waves into a highly directional beam, improving communication range and efficiency.
Meanwhile, the vortex-beam antenna produces a unique corkscrew-shaped wavefront, which can carry additional channels of information. Together, these designs could make communication systems twice as efficient by enabling multiple channels on the same antenna.
Each prototype, approximately one square meter in size, was knitted in just 45 minutes and was durable enough to withstand washing and stretching. This durability and scalability make these fabric antennas ideal for both commercial and industrial applications.
One of the most exciting aspects of this technology is its accessibility. The researchers used off-the-shelf materials and established knitting techniques, making it possible to integrate antennas into everyday items like clothing or blankets. “Imagine a sweater that could boost your WiFi signal,” said Yu. “The possibilities are endless.”
The team is now exploring modern knitting techniques to create fabrics with even more complex functions.
Future designs could incorporate electronic circuits, hinge points, or folds, making the antennas easier to deploy and store. These advancements could lead to large, lightweight antennas that fold up for easy transport, perfect for satellite communications across vast distances.
Because industrial knitting machines can produce fabrics up to two meters wide with no length limit, the potential for scaling this technology is enormous. For instance, it could enable the creation of ultra-large antennas that are lightweight and flexible enough to be carried by satellites, revolutionizing space communication.
The researchers believe their work could open new doors in telecommunications and wearable tech.
By combining aesthetics and functionality, this technology could turn ordinary fabrics into powerful communication tools. As Yu points out, “Communities of knitters might soon be designing sweaters that double as WiFi boosters.”
This innovation marks a significant leap forward in how we think about antennas—turning something rigid and bulky into something flexible, lightweight, and seamlessly integrated into our daily lives.
