Radar could start appearing in a far wider range of devices, including cellphones, thanks to the invention of a fingernail-sized chip package costing just over a dollar.
It could have important uses in the automotive industry, as well as mobile devices, robotics and other applications, say its developers.
"As far as I know, this is the smallest complete radar system in the world,' says Professor Christoph Scheytt, who is coordinating the project on behalf of IHP in Frankfurt, Germany.
"There are other chips working at frequencies beyond 100 GHz addressing radar sensing, but this is the highest level of integration that has ever been achieved in silicon."
Measuring just eight by eight millimeters, the chip package operates at 120 GHz - corresponding to a wavelength of about 2.5 mm. It uses the runtime of the waves to calculate the distance of an object up to around three metres away, with an accuracy of less than one millimetre. It can also detect moving objects and calculate their velocity using the Doppler effect.
And it's cheap: manufactured on an industrial scale, each complete miniature radar would cost around one euro, the project partners estimate. At that size and price, it could find its way into cellphones, says the team.
Because the chip is a standard surface-mount package, application engineers could can handle it in much the same way they'd fit an ultrasonic sensor or microcontroller.
"Users can solder the chip onto their standard circuit boards and receive low-frequency signals that can be processed without difficulty," says Professor Thomas Zwick, head of IHE at the Karlsruhe Institute of Technology.
Several companies are already looking at deploying the technology, including Bosch, as well as Silicon Radar in Germany, Selmic in Finland and Hightec in Switzerland.