Radar systems work by sending out radio waves and using the echoes that bounce back to create an image of an object. Some radar systems use electronics to actively steer their outgoing radio waves, instead of just mechanically sweeping a beam in a fixed pattern. This lets them simultaneously scan the sky for objects and track specific ones with high accuracy. But the complex devices normally needed to steer radio waves around, known as phase shifters, make such electronically scanning radar expensive and bulky.
Driscoll’s
drone carries an electronically scanning radar instrument that doesn’t
have a conventional phase shifter. The outgoing radio waves are steered
with a much simpler device, built using techniques borrowed from a
relatively new area of research on what are known as metamaterials.
This
drone has an advanced electronically scanning radar on board, equipment
usually much too bulky and expensive for such small craft.
Metamaterials
provide a way to get around many of the physical limitations that have
previously defined how engineers could control radio, light, and sound
waves. For example, while conventional lenses need their characteristic
shape to bend light rays into focus, a metamaterial lens can bend light
the same way while being perfectly flat.
Metamaterials
are made from repeating structures that are smaller than the wavelength
of the electromagnetic radiation being manipulated. Echodyne makes its
metamaterials by tracing out repeating patterns of copper wiring on an
ordinary circuit board.
A
board with multiple layers of such wiring can direct radar beams. And
applying different voltages to some parts of the wiring makes it
possible to actively control the beam as a phase shifter would. “Any
printed circuit board manufacturer could produce these,” says Driscoll.
The
radar systems used by the military typically start at around $100,000,
says Eben Frankenberg, CEO and another cofounder of Echodyne. He says
his company hopes to mass produce compact radar systems that cost only thousands of dollars.
Driscoll
says that could make scanning radar become a standard sensor for
vehicles and robots. Some prototype autonomous cars, including Google’s,
use spinning laser sensors (LiDAR) to watch the world around them in 3-D. That
technique can map the world in very high resolution, but its range
decreases in fog or snow. Radar doesn’t have that limitation, says
Driscoll.
Echodyne also plans to offer its systems to the military, and to replace
the radar already in use commercially: the spinning dishes seen on
ferries and other boats that create simple maps by sweeping a beam
around, for example, or the small fixed sensors in some cars that allow
an adaptive cruise control system to keep a safe distance from the car
ahead.
Echodyne was created by the patent licensing company Intellectual Ventures. In 2013, Intellectual Ventures set up a unit dedicated to building a portfolio of patents
for metamaterials, and to figuring out how to commercialize them.
Echodyne has also received investment funding from Microsoft cofounder
Bill Gates, and venture capital firm Madrona Venture Group.
David Smith,
a professor at Duke University who researches metamaterials and has
worked with Intellectual Ventures, says that Echodyne’s approach
provides very flexible ways to control radio waves. The company’s
biggest challenge, he says, is to craft complete radar systems that can
compete in the market. That means matching the performance of very
high-end systems used by the military today to succeed in the defense
market, and carefully controlling costs for applications in the car
industry.
