Terahertz Radar: A New Era in Auto Safety
A few years ago, Matthew Carey lost a friend in a freak car accident, after the friend’s car hit small debris on a highway and spun out of control. Normally, the car’s sensors would have detected the debris in time, but it was operating in conditions that render all the sensors mounted on the car useless today: fog and bright early morning sun. Radar doesn’t see small objects well, lidar is limited by fog, and cameras are blinded by glare. Carey and his co-founders decided to create a sensor that could do the job: a terahertz imager.
Historically, terahertz frequencies constitute the least used part of the electromagnetic spectrum. People had difficulty sending them even short distances through the air. But thanks to intense engineering and improvements in the frequency of silicon transistors, it is now possible to broadcast terahertz radiation over hundreds of meters. Teradar, the Boston-based startup Carey co-founded, has successfully manufactured a sensor capable of meeting the automotive industry’s 300-meter distance requirements.
The company came out of stealth last week with chips that it says can deliver 20 times the resolution of automotive radar while seeing through all kinds of weather conditions and costing less than lidar. The technology provides “a superset of lidar and radar combined,” says Carey. The technology is being tested with automakers for placement in vehicles that will be produced in 2028, he says. This would be the first sensor of this type to be commercialized.
“Every time you unlock a part of the electromagnetic spectrum, you unlock a whole new way of seeing the world,” says Carey.
Terahertz imaging for cars
Teradar’s system is a new architecture, Carey says, that has elements of a traditional radar and a camera. Terahertz transmitters are arrays of elements that generate electronically steerable beams, while sensors are like imaging chips in a camera. The beams scan the area and the sensor measures how long it takes for the signals to return and where they are returning from.
Teradar’s system can direct beams of terahertz radiation without moving parts.Teradar
From these signals, the system generates a cloud of points, similar to that produced by a lidar. But unlike lidar, it uses no moving parts. These moving parts significantly increase the cost of the lidar and subject it to wear and tear from the road.
“It’s a sensor that [has] the simplicity of radar and the resolution of lidar,” says Carey. It’s up to automakers to decide whether it will replace a technology or become a complement, he adds. The company currently works with five of them.
Terahertz transistors and circuits
That Teradar has made it this far is partly due to advances in silicon transistor technology, particularly the steady increase in the maximum device frequency that modern foundries can deliver, Carey says.
Ruonan Han, a professor of electrical engineering at MIT who specializes in terahertz electronics, agrees. These improvements led to an increase in the efficiency of terahertz circuits, their output power and the sensitivity of the receivers. In addition, chip packaging, essential for efficient transmission of radiation, has been improved. In combination with circuit and system design research, engineers can now apply terahertz radiation in a variety of applications, including autonomous driving and safety.
Still, “it’s quite difficult to deliver the performance needed for real, safe autonomous driving, especially when it comes to distance,” says Han. His lab at MIT has been working on terahertz radars and other circuits for several years. For now, the company is focused on developing lightweight, low-power terahertz sensors for robots and drones. His lab has also created an imaging startup, Cambridge Terahertz, which aims to use the advantages of the frequency band in security scanners, where they can see through clothing to spot hidden weapons.
Teradar will also explore applications outside of the automotive sector. Carey points out that even though terahertz frequencies do not penetrate the skin, melanomas appear a different color at these wavelengths compared to normal skin.
But for now, Carey’s company is focused on cars. And in this area, there’s a question I had to ask: Could Teradar’s technology have saved Kit Kat, the feline unfortunately run over by a Waymo self-driving car in San Francisco last month?
“It probably would have saved the cat,” Carey says.
From the articles on your site
Related articles on the web
