Plane Wave Spectrum Filtering Method for Phaseless Planar Near-Field Measurements via Reweighted Amplitude Flow

Due to the susceptibility of phase measurements to various error sources, especially at high frequencies, there is increasing interest in determining far-field patterns using phaseless near-field measurements. The two-scan technique enables accurate phase retrieval (PR) using only amplitude measurements. The source reconstruction method typically requires solving field-source equations, leading to significant computational costs. This letter proposes a method that combines plane wave spectrum expansion with the reweighted amplitude flow algorithm to achieve precise PR while improving computational efficiency. Spectral filtering is utilized to address convergence issues during implementation. Simulations with a Vivaldi antenna demonstrate the robust PR performance of the method proposed in the presence of noise, and its convergence stability concerning the variability of field amplitude on both surfaces due to distance influence, thereby ensuring practical applicability. In addition, experimental validation with a horn antenna confirms the effectiveness of the method proposed.