The incredibly shrinking world of vehicle radar design

The Insurance Institute for Highway Safety claims that one in three fatal car crashes can be mitigated if vehicles are equipped with collision avoidance systems. But the ultrasonic radars used for offering emergency braking and other ADAS features are found mostly in high-end vehicles.

Moreover, a radar sensor carrying out four essential functions — generate, transmit, receive, and digitize radar signals — generally has three to four SiGe chips and that leads to the creation of a bulky device. It’s changing now as car OEMs, and Tier 1 companies are streamlining radar hardware with single-chip transceiver solutions.

So a new breed of automotive radars — forming a cocoon around vehicles to provide 360-degree surround view — could bring crucial security features such as forward collision warning, blind spot detection, adaptive cruise control, and autonomous braking even to mid-range cars.

These radar designs hook up a highly integrated CMOS transceiver chip with an MCU to create a system-level solution for ADAS and autonomous car applications. Take NXP, for instance, which claims that its TEF810X radar transceiver chip integrates the four basic functions and thus reduces the size of radar sensors by 50 percent.

The 76–81GHz front-end radar chip — which Google has been testing in its self-driving cars — will be ready for mass production in 2018 and will show up in cars in 2019. NXP has tied the TEF810X radar transceiver chip with its S32R27 automotive microcontroller to create an ultra-compact system design.

The block diagram of an automotive radar system design comprising of a front-end chip and an MCU. Image courtesy of NXP

ADI has also unveiled a system-level automotive radar solution based on its Drive360 CMOS RF-to-bits technology and RH850/V1R-M microcontroller from Renesas which the firm claims has specifically been designed for radar applications.

ADI says that its 76–81GHz Drive360 radar platform is the first 28nm CMOS solution and that it offers the lowest phase noise while ensuring unambiguous detection of smaller objects in the presence of large objects.

The shift from SiGe to CMOS in front-end radar transceiver chips improves the integration with the digital circuitry and lowers the costs and evaluation risks for automotive OEMs and Tier 1 suppliers. That means more cars can afford automotive radars.