Advances in semiconductor technology allow further miniaturization of radar sensors. A previously unattainable resolution can be achieved with radar sensors, where the small wavelength also makes it possible to integrate antennas on chips or in chip housings. However, the development of the frequency range above 100 GHz has so far been hampered by extremely complex assembly and connection technology. KIT, FhG-IAF and industrial partner Vega have achieved a breakthrough with the SATIRE project.
Radar is increasingly being used at 'close range' - in cars, for example, but also in industrial applications. Advances in semiconductor technology in recent years are now making further miniaturization possible. To this end, researchers at the Karlsruhe Institute of Technology (KIT), in collaboration with the Fraunhofer Institute for Applied Solid State Physics (IAF) in Freiburg and industrial partner Vega Grieshaber KG, are developing ultra-compact radar sensors with a modular design that are also suitable for the diverse requirements of industrial sensor technology.
A previously unattainable resolution is possible with radar sensors, where the integration of antennas on chips or in chip housings is possible due to the small wavelength. However, the development of the frequency range above 100 GHz has so far been hampered by extremely complex assembly and connection technology, which for a long time represented a limitation on the way to cost-effective integrated modules.
Now, variants from the 'Real100G.RF' project of the German Research Foundation (DFG) are being brought together with circuits from Fraunhofer IAF. A scalable miniature radar front end will be developed from this, which will then be evaluated for industrial usability in collaboration with Vega from Schiltach in the Black Forest.
"As the third pillar alongside research and teaching, innovation at KIT stands for the character of research and development activities."
The project 'Scalable THz Miniature Radar for Industrial Applications' (SATIRE) is one of six trilateral projects funded by the DFG and the Fraunhofer-Gesellschaft (FhG). The aim is to transfer scientific findings to industry. In this project, companies can participate in innovations from research at an early stage.
Focus on miniaturization
SATIRE aims to develop a scalable, highly integrated 300 GHz radar sensor with a bandwidth of over 50 GHz and thus a resolution in the millimeter range. The modules, which measure a maximum of 10 x 10 x 7 mm including the lens, can be interconnected on a control board to form a MIMO system ('Multiple Input Multiple Output', a method for using several transmitting and receiving antennas for wireless communication) and can also be used individually. This makes the modules particularly suitable for the diverse requirements of industrial sensor technology. "The project also utilizes the technological possibilities offered by the Research Laboratory Microelectronics Germany at KIT," says KIT President Professor Holger Hanselka. "As the third pillar alongside research and teaching, innovation at KIT stands for the application-oriented character of research and development activities. This innovation activity once again builds a bridge between knowledge and application."
Radar sensors at frequencies above 100 GHz have enormous potential as a supplement to existing optical sensors, whether camera or lidar. "On the one hand, they allow a good resolution with high robustness, for example against smoke or dust," explains Professor Thomas Zwick, project manager and head of the Institute of High Frequency Technology and Electronics (IHE) at KIT. To achieve a resolution in the millimeter range, the circuit must have an output bandwidth of at least 50 GHz with a switchable transmitter for TDM-MIMO operation ('Time Division Multiplex', signal transmission method). Lenses made of ceramic and plastic are being tested, and 3D printing and injection molding are being used. The entire component will be the same size as the lens, i.e. have dimensions of no more than 10 mm. "With our mini radar, we are not only improving measurement performance, but also industrial manufacturability," says Zwick. The small size and precise measurement open up completely new application possibilities. In addition, the architecture with multipliers and an external local oscillator as well as a transmitter that can be switched off allows several radar sensors to be combined on one board to form a MIMO radar.
This results in a versatile radar front end that can be scaled to different systems and is essential for industrial applications, as a large number of applications have to be served here. The project is characterized by its strong practical focus, which gives companies the opportunity to participate in innovations from research at an early stage - in this case the company Vega.
