Kirigami, could shape wireless technology

Researchers from Univ. of British Columbia and Drexel Use Kirigami to Create Tunable Radio Antennas from MXene Nanomaterials

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.

Recently published in the journal Nature Communications, research from the Drexel-UBC team showed how kirigami — a variation of origami — can transform a single sheet of acetate coated with conductive MXene ink into a flexible 3D microwave antenna whose transmission frequency can be adjusted simply by pulling or squeezing to slightly shift its shape.

The proof of concept is significant, according to the researchers, because it represents a new way to quickly and cost-effectively manufacture an antenna by simply coating aqueous MXene ink onto a clear elastic polymer substrate material.

“For wireless technology to support advancements in fields like soft robotics and aerospace, antennas need to be designed for tunable performance and with ease of fabrication,” said Yury Gogotsi, PhD, Distinguished University and Bach Professor in Drexel’s College of Engineering, and a co-author of  the research. “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.

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 this joint work leverages physical shape change and can create antennas in a variety of intricate shapes and forms. These antennas are flexible, lightweight and durable, which are crucial factors for their survivability on movable robotics and aerospace components.

 To create the 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. MXene ink is particularly useful in this application because its chemical composition allows it to adhere strongly to the substrate for a durable antenna and can be adjusted to reconfigure the transmission specifications of the antenna.

MXenes are a family of two-dimensional nanomaterials discovered by Drexel researchers in 2011 whose physical and electrochemical properties can be adjusted by slightly altering their chemical composition. MXenes have been widely used in the last decade for applications that require materials with precise physiochemical behavior, such as electromagnetic shielding, biofiltration and energy storage. They have also been explored for telecommunications applications for many years due to their efficiency in transmitting radio waves and their ability to be adjusted to selectively block and allow transmission of electromagnetic waves.

Using kirigami techniques, originally developed in Japan the 4th and 5th centuries A.D., the researchers made 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 its 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.