Two new millimeter-wave radars debut with a detection distance of 200 meters

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Two new millimeter-wave radars debut with a detection distance of 200 meters [Copy link]

Hitachi and Mitsubishi Electric exhibited smaller automotive millimeter-wave radars, both using the 76GHz frequency band. The two companies plan to start supplying the radars exhibited in 2008. Hitachi　　exhibited a millimeter-wave radar for long-distance detection (detection range 1m to 127m), with dimensions of 100mm wide × 80mm long × 30mm thick (Figure 1). Compared with the original model, the thickness and volume of the module have been reduced to about 1/3 and 1/4 respectively. In addition, the company has also developed a millimeter-wave radar for short-distance detection (detection range 0.1m to 25m), mainly by improving the antenna, expanding the detection angle from ±15 degrees of the long-distance detection radar to ±35 degrees. The millimeter -wave radar mainly consists of three parts: antenna, high-frequency circuit and signal processing unit. In order to reduce the thickness of the millimeter-wave radar, Hitachi improved the high-frequency circuit and signal processing part. As for the high-frequency circuit, the volume was reduced　　by encapsulating the MMIC chip on a multilayer printed circuit board. Compared with the radar using a single-layer printed circuit board, the packaging density of high-frequency components has been greatly improved. 　　The number of microprocessors equipped in the signal processing part has been reduced to one. The previous radar used a total of two microprocessors, one for millimeter wave frequency conversion and calculation of detection results, and the other for processing communication with the in-vehicle LAN. However, this time, "while improving the performance of the microprocessor, all processing is concentrated on one microprocessor by increasing the storage capacity of the mixed-load memory " (the company's commentator). However, the specific specifications of the microprocessor were not announced this time. Since the number of microprocessors has been reduced, the internal heat generated by the signal processing part has also been reduced, thereby improving the packaging density of the components. At the same time, this has also contributed to the miniaturization of the signal processing part. The maximum detection distance is 200m.　　Mitsubishi Electric's millimeter wave radar has a module thickness reduced from 76mm to 60mm (Figure 2). In terms of millimeter wave transmission and beam scanning technology, "the original radar already has quite excellent performance" (the company's commentator), so this time, the antenna and high-frequency circuit were not improved, but only the signal processing part was improved. However, the details of the miniaturization technology were not announced this time, only the number of components was reduced. 　　While reducing the size, Mitsubishi Electric has increased the detectable distance to a maximum of 200m by improving the algorithm for calculation and processing. The original radar was only 150m. This distance is even longer than the prototype radar of Hitachi, Ltd. mentioned above. The main reason for increasing the detectable distance to 200m is that "if it is in Europe, especially on the German highways where the car cruising speed is high , the detectable distance of 150m seems a bit inadequate. If it can reach 200m, it will be enough" (Mitsubishi Electric commentator). 　　Millimeter wave radar detects the distance between vehicles and the position of vehicles by receiving the emitted millimeter waves reflected by the vehicle in front. This time, the algorithm was comprehensively improved to improve the reception sensitivity of millimeter waves. In addition, it is reported that the microprocessor that runs the calculation software is not much different from the original type used.