K-Space Analysis of Aliasing in Millimeter-Wave Imaging Systems

This article focuses on analyzing the aliasing artifact in millimeter-wave imaging systems, with a special focus on multistatic arrays. The current framework to analyze the behavior of multistatic structures is based on the effective aperture concept. Based on this framework, an equivalent monostatic array, approximating the position of each transmitter-receiver pair by its midpoint, is used to quantify the response and efficiency of the system. Although this framework helps to simplify the study of the complex characteristics of multistatic arrays, it suffers from vital deficiencies. Especially, it fails to describe the aliasing artifacts, seen in the image of some sparse multistatic configurations, where the study of their equivalent monostatic arrays proves that the Nyquist sampling rate is satisfied. In order to explain such behaviors, we propose a k-space-based framework to evaluate multistatic imaging systems. This framework not only explains the reason behind the aliasing artifacts but also estimates the locations where the aliasing happens. Moreover, this analysis can be beneficial to design multistatic configurations with reduced aliasing artifacts. The provided simulations and the experimental results prove the accuracy of the proposed framework that can effectively estimate the occurrence and the place of aliasing artifacts.