Flexible hybrid electronics have commercial UAS applications

By Patrick C. Miller | November 21, 2018

Flexible hybrid electronics—sometimes called peel-and-stick electronics—could soon be used to monitor the health of unmanned aircraft systems (UAS) operators and control drone flight, while also enabling UAS to carry electronics considered too heavy or bulky several years ago.

For example, Lockheed Martin Corp. is studying the use of 3D printed electronics that conform to the wing surface of its small, fixed-wing Desert Hawk unmanned aerial vehicle (UAV) to provide beyond-line-of-sight satellite communications. Two miniaturized phased-array antennas—one for transmitting and one for receiving—can be applied to each wing surface of the man-portable UAV using flexible hybrid electronics (FHE) technology.

“One of the limitations for these small UAVs is that they only have line-of-sight communications using wi-fi,” said Stephen Gonya, a Lockheed Martin Fellow research scientist in advanced manufacturing technology. “What we want is beyond-line-of-sight or over-the-horizon satellite communications. They don’t make antennas that small to fit on UAVs.”

Hong Yeo, an assistant professor of micro and nano engineering at the Georgia Institute of Technology in Atlanta, has demonstrated the potential of using FHE technology and muscle movements to control a drone. Although his primary area of research studies the use of eye, muscle and brain signals to control prosthetics and other biomedical devices, Yeo showed how a wearable FHE patch on his forearm could be used to fly a drone.

“It’s made of a bandage-like substance—a very soft and flexible material,” he explained. “One side is making direct contact with the skin and the sensors. The other side includes the electronic circuit and components—also made of flexible and stretchable components—to power the device and transmit the data wirelessly from Bluetooth to the target drone.”

Georgia Tech and Lockheed Martin are members of NextFlex, a public-private partnership based in San Jose, California. The organization was launched in 2015 under a cooperative agreement with the U.S. Department of Defense to advance the manufacturing of FHE technology. Lockheed Martin and Georgia Tech plan to submit a proposal to the organization for a project using FHE and 3D printing. Two phased-array antennas on a small UAV will incorporate beam steering on a millimeter wave frequency—technology normally limited to much larger UAS.

Gonya said the satcom antenna would enable the UAV to operate over the horizon or when a geological feature—such as a mountain—is between the operator and the drone. In addition, the antenna system enables the UAV to transmit low-resolution video or high-definition images in real time, which is useful for military surveillance, reconnaissance and intelligence gathering. However, Gonya noted that there are a variety of civil applications for the technology, including search and rescue, emergency response, disaster monitoring, scientific research, surveying and infrastructure inspection. 

“We’re looking at designs to get FHE technology inserted into Lockheed Martin products,” Gonya said. “Next year, we’ll be doing designs and reliability testing to get it on to a real platform. We’ve done many 3D antennas and microwave circuits. We’re starting small and increasing the content as the technology matures and we get more comfortable with it.”

According to Malcom Thompson, NextFlex executive director, there are many other practical uses for FHE technology being studied by more than a hundred of its members representing government agencies, private companies and academic institutions. Wearable electronic devices can be put on soldiers in the field, athletes and drone pilots to monitor their health and stress levels. They can also be put on objects, such as bridges, aircraft engines and pipelines, to monitor performance and identify potential structural failures.

“What we do is take a very thin plastic substrate—a polymer substrate—and we print conductors and insulators and other kinds of materials on to it for the interconnections between the components. We’re actually ink-jet printing metals like silver and copper,” Thompson explained. “You then encapsulate it with a very thin film of material to protect it.”

FHE components are flexible and can be bent, stretched and twisted. Thompson said they’re also extremely lightweight. “We built an Arduino board that people make and design circuits on; our flexible Arduino weighs less than a third of the weight of the rigid Arduino board most people use,” he said.

In addition, Thompson said it takes 19 process steps to manufacture a conventional circuit board, compared to seven to make a flexible FHE board. “It’s a much simpler manufacturing process,” he noted. “It’s cheaper and has a much faster time to market, converting a digital file into a circuit very quickly.”

NextFlex has a technology hub where members can fabricate fully integrated systems in a pre-commercial setting and conduct pilot-scale manufacturing.

“We want to accelerate these products to help our members get their projects to market at low risk in a cost-efficient way,” Thompson said. “Some of our members are high-volume manufacturers. The activity we do inside our hub with our pilot line can easily be passed on to our members to scale for high-volume production.”