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- The Visual Block of Existing Antennas
- What's Inside Transparent Antennas
- Applying the Antennas to Windshields
- Marketing the Transparent Antennas
Several manufacturers of Internet of Things (IoT)-based antennas are developing products that leverage a new material from Chasm that is nearly transparent, making it possible for IoT or radio frequency identification (RFID) sensors and tags to be applied in places where traditional antennas have caused a visual disruption in the past, such as on car windshields. The new antennas are designed to hide in plain sight, the company reports, so that they can remain unobtrusive to users, though not entirely invisible.
Chasm was launched in 2015 to develop and manufacture advanced materials enabling products with greater performance and improved sustainability. The company uses carbon nanotubes (CNT) built into its materials to provide strength, flexibility and conductivity, while enabling near-transparency. Chasm also makes transparent heaters, low-carbon cement and battery materials.
Chasm's AgeNT hybrid transparent conductor technology
Global antenna and advanced IoT components provider Taoglas has launched three invisible antenna products that are enabled by Chasm's hybrid transparent conductor technology, known as AgeNT. It is now marketing the antennas to bring connectivity to vehicles without requiring added cabling or alternations to the vehicle frames. Instead, users can simply peel the device and stick it to a windshield.
The Visual Block of Existing Antennas
A large percentage of a typical RFID tag's footprint is the antenna, which often consists of a copper wire that surrounds the IC on which the tag data is stored. Therefore, some applications for RFID tags and IoT products can be limited based on aesthetics. Putting an antenna on glass, for instance, would disrupt the appearance of the glass, as well as inhibit visibility.
David Arthur
Additionally, some IoT device manufacturers have opted to build the wireless antenna into devices, underneath other materials, in order to hide it, and that means performance can be affected as well. That's a major shortcoming related to these printed circuit board-based antennas, according to David Arthur, Chasm's CEO and cofounder. "They need to be packaged [as part of a non-transparent tag]," he explains, "and they will either attract attention to the antenna or they'll block the view if they're mounted to glass."
On the other hand, Arthur says, a transparent antenna would give IoT product developers more design freedom with respect to antenna placement. Chasm has been working on developing a transparent antenna solution for years, he reports, and the company plans to commercially release the results of that development this year.
Arthur says the product is being demonstrated on a range of antennas, whether they transmit Bluetooth Low Energy (BLE) signals, Wi-Fi, ultra-wideband (UWB), 5G, GNSS (satellite), ultrahigh-frequency (UHF) RFID or Near Field Communication (NFC). With the new material, the company says, antenna makers can evolve from a non-transparent printed circuit board-based antenna to one that is transparent. "We can do that at low cost," he states, "in mass production."
What's Inside Transparent Antennas
The antenna material consists of a micro-mesh of very fine copper wires, measuring 5 microns (0.0002 inch) in width, in a diamond pattern. To put the width of the copper wires into context, anything sized below approximately 8 microns (0.0003 inch) is difficult for the human eye to see. Thus, when looking through Chasm's mesh, individuals will not see the copper.
Between the wires is a lot of open area through which light will pass, comprising approximately 85 to 95 percent of the total mesh area. The copper is thick enough to carry a current, though not as effectively as a wider piece of copper would. So the antenna material leverages printed carbon nanotubes that lay over the copper micro-mesh in the form of a screen-printable ink, providing the conductivity boost needed in the mesh's open spaces.
The carbon nanotubes serve a very important role, Arthur says. They are among the strongest materials known, he explains, so they provide mechanical reinforcement for the tiny wires that make up the copper micro-mesh. In this way, he says, the conductive carbon nanotubes can circumvent cracks in the tiny wires, like a self-healing, conductive film. "We call it a hybrid transparent conductor," Arthur states, "because it's a hybrid of carbon nanotubes and the copper micro-mesh."
The nanotubes being used are what is called single-wall carbon nanotubes (SWCNTs), as opposed to a multi-wall version. To put it simply, Arthur says, it only takes one wall to conduct electricity. While more commonly available carbon nanotubes contain as many as 10 walls, the other nine absorb light, adding no value when it comes to conductivity. "So we grow single-wall carbon nanotubes," he says, "and we disperse them into an ink that can be printed. Only a tiny amount of carbon nanotubes is needed to do the job."
The bottom line for users, Arthur reports, is that the antenna is transparent enough that it potentially might not be detectable if people aren't paying attention. When it comes to performance, he says, the company found in its internal testing that the flexible antenna comes close to that of premium RF microwave-grade printed circuit boards. The combination of copper micromesh and carbon nanotubes makes that possible, he adds.
Applying the Antennas to Windshields
The antennas are predominantly being used on car windshields to provide IoT functionality. While operators are demanding greater connectivity with the outside world while driving or using their vehicles, Chasm reports that the real estate for antennas is limited. Cars have ample glass surface in the form of windows and windshields, but users and manufacturers are reluctant to cover this space for fear of hindering visibility. On the other hand, users cannot mount an antenna behind metal, as the antenna simply would not operate properly.
In many cases, that means IoT connectivity requires the drilling of holes in vehicle frames and the mounting of antennas outside of the metal, such as on the roof. Chasm's antenna is designed to be peeled and stuck to a surface like glass, Arthur says, which would make the application less expensive compared to integrating an antenna into a vehicle. "You wouldn't want to put it right in front of the direct vision of a driver," he states, "but you could put it on several other spots on the windshield, or on the rear window, or on the sunroof."
Taoglas specializes in IoT and connectivity solutions for public safety and transportation vehicles, and it offers several versions of a transparent antenna solution that could be attached to plastic, glass and screens. By offering clear, flexible antennas for glass, the firm provides savings in terms of the cost users would otherwise incur upgrading a vehicle by drilling holes to install antennas. Beyond cars, Taoglass expects other applications to include the use of such antennas on window glass to create smart, connected buildings, and other applications such as EV chargers and parking meters.
When it comes to IoT devices, the antennas could be applied to the exterior, where they would have better transmission functionality without disrupting the look of the device. One example could be NFC tags. For instance, companies employing NFC technology—operating at 13.56 MHz and compliant with the ISO 14443 standard—for brand protection could build the antennas into labels used on luxury products, such as bottles of wine or perfume. In that way, Chasm explains, the labels would be less visible and consumer would see only the products and the printed labels.
Marketing the Transparent Antennas
Chasm is selling its material to antenna companies and device manufacturers. "We're not antenna designers," Arthur notes. "We are a materials company, and so we work with other parties that are antenna design experts." The antennas have been tested across a range of frequencies, he reports, from satellite to NFC and HF RFID. While there are other companies offering transparent antennas, what differentiates Chasm's product, the company claims, is that it is thin, flexible, designed for convenience and in a peel-and-stick format, as opposed to being made of glass.
According to Arthur, antennas using the transparent material will be somewhat more expensive than traditional antennas at the circuit board level. "But at the system level," he adds, "we believe we're cheaper," considering that there is no additional cost for packaging, and that users do not have to put the antennas within a housing. He cites other potential savings related to installation as well. "Because you can put it wherever you want to, on glass typically, the amount of cabling is less," he says. "So the installation cost is lower, the cabling cost is lower [and] you don't have the packaging cost."
Chasm can produce prototypes at its facility in the Boston area, says Ina Jiang, the company's VP of marketing, and can carry out early-stage production at that facility. The firm teams up with certified fabricators in Europe and the Asia Pacific region, in addition to its own production site in the United States. It currently can produce more than 10 million antennas annually, and it plans to add additional fabricators to its network going forward, Arthur says. "As demand grows," he adds, "it will not be difficult for us to add fabricators, because we use pretty standard printed circuit board fabrication methods."
The company's goal is to reach antenna makers and their customers, in order to offer them a trial of nontransparent products. "That could be [the] antenna producer, device manufacturer or system integrator," Arthur says, adding that Chasm would help them design their own IoT products. For businesses that prefer to produce the transparent antennas themselves, Chasm offers potential partnerships to enable that arrangement, along with its patented AgeNT material.
Key Takeaways:
- Chasm has developed a material known as AgeNT, with very fine copper mesh and carbon nanotubes, to make antennas highly conductive and nearly transparent.
- Taoglas and other companies are utilizing the material to create antennas for IoT or RFID tags that can be applied to glass windshields.
