European consortium develops monolithic 122-GHz radar sensor

September 20, 2012 // By Peter Clarke
A European consortium has developed monolithic 122-GHz radar sensor suitable for use in automotive parking, distance and speed measurement applications. The surface-mountable package measures 8-mm by 8-mm. It includes a mixed-signal silicon germanium (SiGe) BiCMOS millimeter wave IC and antennas for transmitting and receiving.

The SUCCESS (Silicon-based Ultra Compact Cost-Efficient System design for mm wave Sensor) project, which includes Robert Bosch and STMicroelectronics amongst others, began in December 2009 with a 4.8 million euro (about $6.1 million) budget for a period of three years, of which the European Union was scheduled to provide 3.0 million euro (about $3.8 million).

The project was expected to work on the issues of plastic surface mountable housings, system-in-package including a planar antenna and links to a radar front-end IC and baseband processor. In addition, to reduce the cost of testing methods were scheduled to be devised for built-in-self-test and the test of SiP.

Monolithic integration of the digital baseband processor, data converters, and mm-wave circuitry on the same chip enables the fabrication of complete mm-wave sensor electronics at cost of well below 1 euro (below about $1.30). Furthermore millimeter wavelength radio waves result in millimeter-sized antennas that can be integrated in the chip package. Hence a millimeter sensor can be realized using a system-in-package approach.

The first prototype was implemented in July 2012. The sensor is based on a mixed-signal chip fabricated in a 0.13-micron SiGe BiCMOS technology from IHP. The homodyne transceiver, which was designed by IHP and Silicon Radar GmbH, includes a 120-GHz voltage-controlled-oscillator, several amplifiers, an IQ-mixer and filters.

Additional circuits are added that allow built-in-self-testing, such as power detectors and a frequency measurement unit. Parts of the transceiver are controlled digitally using an SPI interface. The chip is packaged in a novel technology developed by the Karlsruhe Institute of Technology (KIT), Robert Bosch GmbH, Selmic and Hightec MC AG. KIT designed the transmitting and receiving antennas that are integrated into the package. As the antennas are integrated into the package, only DC and baseband signals need to be transmitted to the package.

The antennas are fabricated on a thin, flexible polyimide material and the metallic ground plane of the ceramic housing acts as a