A Joint Design of Sparse Array Layout and DOA Algorithm for mmWave FMCW Radar

Sparse distribution of array elements is commonly employed to increase the virtual aperture size for improving angular resolution. However, it can lead to elevated levels of sidelobe and grating lobes that introduces angular ambiguity and false detections if element spacing is more than half wavelength. This paper proposes a joint design approach of sparse array layout design and the direction-of-arrival (DOA) algorithm. The objective is to address angular ambiguity in sparsely distributed arrays and uses a low-complexity DOA algorithm to facilitate the requirement of real-time processing. The approach involves incorporating the principle employed in the DOA processing into the cost function during the antenna array synthesis. Experimental results obtained from a two-chip cascaded frequency-modulated continuous wave (FMCW) mmWave radar which employs the mentioned joint design approach in this paper demonstrate an achieved azimuth resolution of O. 8° with 0.4° accuracy.