Abstract: Large-spacing phased arrays offer significant advantages in reducing system cost, energy consumption and complexity, but their application is severely limited by inherent grating lobes during wide-angle scanning. To overcome this critical limitation, this paper introduces a novel "null multiplication" mechanism for grating lobe cancellation. The core principle involves partitioning the array into subarrays composed of null-reconfigurable antenna elements. It then systematically leverages the synergistic product of the nulls from the subarray factor and the element pattern to create a composite null. This synthesized null is sufficiently wide and can be dynamically steered to precisely track and suppress the grating lobes. This paper analyzes its physical principle in detail and establishes the mapping relationship between grating lobes and null width. A practical 2D null-reconfigurable element is designed to validate the concept. Simulation results demonstrate that for arrays with element spacing up to 2.0λ, the method achieves effective suppression within a wide ±75° scanning range, confirming its high efficiency and practicality.