Application of the Sunflower Array in Sparse Phased Radar

This paper presents an aperiodic sunflower array. The positions of the antenna elements are directly obtained using a formula, resulting in a lower maximum sidelobe level over a bandwidth with a frequency ratio exceeding 25:1. Additionally, to enhance the directivity of the proposed antenna, all original antenna elements are replaced with a 4×4 antenna subarray. Each subarray's 4×4 antenna elements are synthesized through a passive power divider network and connected to the TIR component, with negligible cost increases to the antenna array. The adjacent subarray spacing is about 3λ. Additionally, the maximum sidelobe levels for the proposed sunflower array in the transmitting and receiving states are -17.5 dB and -29 dB, respectively. The maximum sidelobe level remains below -12 dB when the beam direction is scanned to 15°. Hence, this indicates that the proposed sunflower array has the capability to suppress grating lobes, making it highly promising for the design of large-spacing sparse arrays.