Sub-terahertz sensor could help autonomous cars see through fog

Sub-terahertz wavelengths are between microwave and infrared radiation on the electromagnetic spectrum and can be detected through fog and dust clouds. A sub-terahertz imaging system sends an initial signal through a transmitter, then a receiver measures the absorption and reflection of the rebounding wavelengths. That sends a signal to a processor that recreates an image of the object.

The output signal can be used to calculate distance, similar to how LiDAR uses a laser to hit an object and rebound off it. By combining the output signals of an array of pixels and steering the pixels in a certain direction, high-resolution images can be formed. This not only allows for object detection but also recognition, something that’s crucial for higher level autonomous driving and advanced robotics functions. The work appears in the journal IEEE Xplore.   

"A big motivation for this work is having better 'electric eyes' for autonomous vehicles and drones," said co-author Ruonan Han, an associate professor of electrical engineering and computer science, and director of the Terahertz Integrated Electronics Group in the MIT Microsystems Technology Laboratories (MTL). "Our low-cost, on-chip sub-terahertz sensors will play a complementary role to LiDAR for when the environment is rough."