3D Printing Flexible Antenna Arrays
WSU researchers 3D printed flexible antennas using a novel copper ink and a smart chip that self-corrects signal errors in real-time.
Oftentimes, antennas used for long-range communication are big and bulky — especially when the directionality of an antenna array is needed. That may be fine for radio broadcasts, but when cars, airplanes, or wearable electronics need to transmit wireless signals, these traditional options are not very practical. Thin, flexible antennas that can conform to any shape would be a much better solution, allowing them to disappear into the structure of whatever object requires them.
Flexibility and antennas do not mix well, however. Previous efforts to build flexible antenna arrays have suffered from serious deformation-induced beam pointing errors. Furthermore, the technologies used to make these antennas flexible are very expensive, and they also result in performance degradation over time. But now, a group led by researchers at Washington State University has come up with a novel way to 3D print flexible antenna arrays without deformation-induced beam pointing errors, excessive costs, or performance degradation.
To make this possible, the team combined a new copper-based ink with a custom-built processor chip to create a proof-of-concept flexible antenna array that can correct its own signal distortions in real-time. This work could enable lightweight, shape-conforming antennas for vehicles, aircraft, drones, and wearable electronics — or even textiles capable of sending and receiving data wirelessly.
A key component in the new antenna is a copper molecular decomposition (CuMOD) ink, developed in collaboration with the University of Maryland and Boeing. Traditional printed antennas have often relied on silver inks, which are expensive and prone to high resistivity, or copper inks that oxidize quickly and degrade. CuMOD avoids both problems by using molecular copper formate, which decomposes cleanly to form ultra-thin, highly conductive copper films. The ink exhibits less than 0.1% change in resistivity per degree Celsius, making it nearly as stable as bulk copper, and it maintains performance under bending, high humidity, temperature variation, and even salt exposure.
To build the antennas, the researchers used 3D printing to deposit the CuMOD ink in precise patterns on a flexible Pyralux substrate. Each printed element acts as part of a larger antenna array. Unlike traditional rigid arrays, these conformal designs can bend and flex along curved surfaces without losing electrical integrity. The team tested individual antennas and found that more than 99% of the signal is transmitted even when stretched or heated.
To solve the problem of signal distortion caused by physical deformation, such as vibrations on an aircraft wing or bending on a wearable device, the team developed a dynamic beam-stabilized processor chip. This miniature silicon processor constantly monitors the signal from each antenna element, detecting any phase or gain shifts caused by motion or material changes. It then compensates for those shifts in real time by adjusting the signal phase and delay for each antenna element, keeping the beam precisely aligned.
The researchers demonstrated the system using a lightweight, flexible array composed of four tiles, each containing four antennas connected to a beamforming integrated circuit. Together, the 16 antennas successfully transmitted and received signals while being bent and moved, all while maintaining a stable communication link.
Using this type of technology, our world could be even more connected in the future — and without the cumbersome antennas of today.
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