The many use cases for drones are now clear. They can help tend crops more efficiently, find people lost in the wilderness, and even carry packages. How drones can be widely used for such things safely is much less certain.

The U.S. Federal Aviation Administration says it won’t allow small drones to go beyond their pilot’s line of sight until technology is developed that allows the small fliers to detect and avoid other aircraft. That restriction would ground ideas like Amazon and Google’s plans for package delivery and make many others less lucrative.

A gadget the size of a paperback novel unveiled Monday by Seattle-area startup Echodyne might help pacify the FAA. The company has developed technology that simplifies and shrinks the complex antenna array needed to make a scanning radar system that operates like those of military and commercial aircraft.

Echodyne does it using metamaterials, carefully designed structures capable of manipulating electromagnetic signals in ways impossible for conventional metals and other materials (see “Metamaterial Radar May Improve Car and Drone Vision”).

Although scanning radar has been tested for drone monitoring and traffic control systems, the technology’s size and expense has ruled it out of most work on the problem of how to make drones better at detecting other aircraft, says Eben Frankenberg, Echodyne’s CEO. The company has received $15 million in funding from investors including Microsoft cofounder Bill Gates.

Benjamin Trapnell, an associate professor at the University of North Dakota who works on drone operations and safety, says that scanning radar could be a good solution to drones’ safety problem. Not only can it look for aircraft across a wide field of view, but it can track any that are detected in detail while still watching the rest of the sky, he says.

A handful of companies working with Echodyne, which Frankenberg declines to identify, will receive the new device—called the Mesa-K—to test in about a month. Flight tests by those partners and Echodyne itself should prove that its system can do what’s necessary to keep drones and people around them safe, he says. “In rural areas you need to look out for crop dusters and parasails,” says Frankenberg. “In a city environment or more congested area you want to avoid both manned aircraft and other drones.”

The Mesa-K can only detect objects up to 500 meters away because it has options built in intended to make it easy to experiment with for uses besides drones, such as to help autonomous cars sense their surroundings. A second version designed just for drones will be available later this year, and have a range of up to three kilometers. Frankenberg estimates that ultimately he can make radar systems that add just a few thousand dollars to the cost of a commercial drone.