From Event: SPIE Defense + Commercial Sensing, 2023
In recent years, low-cost millimeter-wave CMOS-IC radar have become available. Millimeter-wave radar has been applied to automotive and other applications because of its superior environmental tolerance compared to cameras and LiDAR. On the other hand, it is inferior to other sensors in terms of spatial resolution(recognition), making target detection accuracy an issue. MIMO Radar, also known as virtual array, is one of the promising technologies to improve spatial resolution, but a commercial CMOS-IC generally has only a small number of antennas, which limits the performance improvement. To solve this problem, a recent trend is to increase the number of real antennas by cascading multiple CMOS-ICs on a single substrate, thereby increasing the array aperture size of the virtual array and significantly improving spatial resolution. However, when using such a method, reflected waves from targets in short range areas cannot be regarded as plane waves but become spherical waves, where target DoA estimation with conventional(far-field) mode vector degrades accuracy. This paper presents a method to achieve improved spatial resolution and suppressed performance degradation in near-field areas without any compensations of conventional mode vector, by simply laying the multiple boards side by side to form overlapped virtual array elements, even if the board consists of a single CMOS-IC. Computer simulations and fundamental experiments show that the proposed method can ideally achieve spatial resolution and DoA estimation accuracy, even when the target is at 0.5m.
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Hiroki Mori, "Near-field target detections by using far-field mode vector in cooperative sensing of commercial millimeter-wave MIMO radar modules," Proc. SPIE 12535, Radar Sensor Technology XXVII, 125350L (Presented at SPIE Defense + Commercial Sensing: May 02, 2023; Published: 15 June 2023); https://doi.org/10.1117/12.2663311.6328503433112.
