The future of wireless technology, from charging devices to boosting communication signals, relies on the antennas that transmit electromagnetic waves becoming increasingly versatile, durable and easy to manufacture. Researchers at Drexel University and the University of British Columbia believe kirigami, the ancient Japanese art of cutting and folding paper to create intricate three-dimensional designs, could provide a model for manufacturing the next generation of antennas.
As published in the journal Nature Communications, the Drexel-UBC team showed how kirigami — a variation of origami — can transform a single sheet of acetate coated with conductive ink into a flexible 3D microwave antenna whose transmission frequency can be adjusted simply by pulling or squeezing to slightly shift its shape.
A team of Drexel-UBC researchers created test antennas by coating acetate with a special conductive ink, then used kirigami techniques to make a series of parallel cuts. Pulling at the edges of the sheet triggered an array of square-shaped resonator antennas to spring from the treated two-dimensional surface. Source: Nature CommunicationsResearch co-author Dr. Yury Gogotsi, from the Drexel team, explains that “kirigami is a natural model for a manufacturing process, due to the simplicity with which complex 3D forms can be created from a single 2D piece of material.”
The researchers believe their proof of concept is significant because it represents a new way to manufacture an antenna quickly and cost-effectively by simply coating aqueous MXene ink onto a clear elastic polymer substrate material.
Standard microwave antennas can be reconfigured either electronically or by altering their physical shape. However, adding the necessary circuitry to control an antenna electronically can increase its complexity, making the antenna bulkier, more vulnerable to malfunction and more expensive to manufacture. By contrast, the process demonstrated in the kirigami study leverages physical shape change and can create antennas in a variety of intricate shapes and forms. These antennas are flexible, lightweight and durable — all of which are crucial factors for their survivability on movable robotics and aerospace components.
To create their test antennas, the researchers first coated a sheet of acetate with a special conductive ink, composed of a titanium carbide MXene, to create frequency-selective patterns. They then used kirigami techniques to make a series of parallel cuts in the MXene-coated surface. Pulling at the edges of the sheet triggered an array of square-shaped resonator antennas to spring from the two-dimensional surface. Varying the tension caused the angle of the array to shift — a capability that could be deployed to quickly adjust the communications configuration of the antennas.
The kirigami antennas proved effective at transmitting signals in three commonly used microwave frequency bands: 2-4 GHz, 4-8 GHz and 8-12 GHz. Additionally, the team found that shifting the geometry and direction of the substrate could redirect the waves from each resonator.
The frequency produced by the resonator shifted by 400 MHz as its shape was deformed under strain conditions — demonstrating that it could perform effectively as a strain sensor for monitoring the condition of infrastructure and buildings.
According to the research team, these findings are the first step toward integrating the components on relevant structures and wireless devices. With kirigami’s myriad forms as their inspiration, the team will next seek to optimize the performance of the antennas by exploring new shapes, substrates and movements.
