4D millimeter wave radar opens a new growth cycle for the industry

The "4D" in 4D millimeter-wave radar refers to the four dimensions of height, distance, azimuth, and speed. Compared with traditional millimeter-wave radars, 4D millimeter-wave radars have added the output of "height" dimension detection information. 4D millimeter-wave radars achieve pitch angle measurement by changing chip technology and increasing the number of longitudinal antennas. The principle of 4D millimeter-wave height information output is similar to that of azimuth, and the angle measurement is calculated by using the phase difference of the same echo signal from different receiving antennas. Millimeter-wave radars use single-chip transceivers, and the pitch angle measurement needs to be achieved by increasing the number of virtual channel MIMOs (number of virtual channels = number of receiving antennas × number of transmitting antennas). The core of outputting height information is to increase the number of longitudinal antennas. Different from the single-chip form of traditional CMOS millimeter-wave radars, 4D millimeter-wave radar chips achieve an increase in the number of virtual channels through three technologies: cascading, single-chip integration, and virtual aperture algorithm, thereby increasing more return points to receive height information.