AWR White Papers

Radar Systems

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mmWave Automotive Radar and Antenna System Development As modern vehicle development expands to include more and more sophisticated electronics, automobile manufacturers are equipping their new models with advanced driver-assistance systems (ADAS) to obtain high safety ratings by increasing automotive safety. Most road accidents occur due to human error, and ADAS are proven to reduce injuries and fatalities by alerting drivers to and assisting them with a variety of issues, including collision avoidance and low tire pressure using radar technology mostly focused over the 76 to 81GHz spectrum. They perform over a range of applications, operating conditions, and object detection challenges in order to provide reliable coverage over the range (distance) and field of view (angle) as dictated by the particular driver-assist function. This application example presents some of the challenges behind developing millimeter-wave (mmWave) radar systems and the antenna array technologies for the next generation of smart cars and trucks. Examples will be presented demonstrating how the AWR Design Environment platform, specifically the radar design capabilities within AWR VSS system design software, can be used successfully in ADAS applications. ADAS Technology ADAS is made possible through a network of sensors that perform specific safety functions. Manufacturers are currently implementing these systems based on vision sensor technology and radar systems operating at either 24 and/or 77GHz. Vision systems detect lane markings and process other visual road information, however, they are susceptible to inadequate performance due to precipitation, particularly snow and fog, as well as distance. On other the hand, long-range radar (LRR) supports multiple functions, comfortably handling distances between 30 and 200 meters, and short-range radar (SRR) can detect objects below 30-meter distances. While the 24GHz frequency band, which addresses SRR detection, is expected to be phased out of new vehicles by 2022, today it is commonly found in hybrid archi- tectures. Meanwhile, the 77GHz band (from 76-81GHz) supporting LRR is expected to provide both short and long-range detection for all future automotive radars. Figure 36 provides details on short/medium and long-range radar. Figure 36: Different ranges, fields of view (FOV), and functions for advanced driver assist systems Technical advantages of the 77GHz band include smaller antennas (a third of the size of the current 24GHz ones), higher permitted transmit power, and, most importantly, wider available bandwidth, which enables higher object resolution. As a result, advances in radar modulation techniques, antenna beam steering, system architecture, and semiconductor technology are driving the rapid adoption of mmWave radar in future ADAS enabled cars and trucks. To manage the adoption of these technologies, radar developers require RF-aware system design software that supports radar simulations with detailed analysis of RF front-end components, including nonlinear RF chains, advanced antenna design, and channel modeling. Co-simulation with circuit and EM analysis provides an accurate representation of true system performance prior to building and testing costly radar prototypes. AWR software provides these capabilities, all within a platform that manages automotive radar product development— from initial architecture and modulation studies through the physical design of the antenna array and front-end electronics based on either III-V or silicon integrated circuit (IC) technol- ogies. Radar Systems 27

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