Hasheminasab Maryam, Cheldavi A, Kishk Ahmed A
Electrical Engineering Department, Iran University of Science and Technology, Tehran, 1684613114, Iran.
Engineering, Computer Science and Visual Arts Integrated Complex, Concordia University, Montreal, H3G 1M8, Canada.
Sci Rep. 2023 Jul 23;13(1):11894. doi: 10.1038/s41598-023-39024-6.
Antenna arrays offer advantages in terms of spatial diversity, allowing for control over pattern specifications in space. The incorporation of frequency diversity in arrays presents an opportunity to manipulate beams in the Space-Time domain. Unlike conventional arrays, Frequency Diverse Arrays (FDA) with added frequency diversity exhibit time-variant and range-dependent patterns. These time variations impact both steering and auto-scanning applications. The array factor is influenced by the coherent interplay between frequency and spatial distributions of elements, thereby correlating the spatial and temporal behavior of the FDA's pattern. To address this space-frequency coherency, an adjoint spatial-frequency design algorithm is the most effective approach to controlling the array's spatial and temporal behavior. Given the complexity of the array factor formulations in FDAs, elements' frequency and spatial distribution have traditionally been designed separately. However, this study proposes an algorithm that simultaneously allocates the location and frequency of elements to achieve a desired pattern. Symmetrical FDA is initially designed using a straightforward formulation of the array factor obtained through symmetry, ensuring a stable and periodic scanning beam. Subsequently, two important design parameters and several crucial design criteria for scanning applications are suggested by analyzing the formulations. These parameters form the basis of a designing algorithm that enables the simultaneous design of element location and frequency in the space-frequency plan, thus meeting the temporal and spatial requirements of the pattern. To demonstrate the efficacy of the proposed algorithm, two different planar arrays are designed, and their results are compared with those of other planar configurations. This study lays the foundation for a novel approach to designing Frequency Diverse Arrays (FDAs), opening up new possibilities in array design.
天线阵列在空间分集方面具有优势，能够控制空间中的方向图规格。在阵列中引入频率分集为在时空域中操纵波束提供了机会。与传统阵列不同，具有额外频率分集的频率分集阵列（FDA）呈现出随时间变化且与距离相关的方向图。这些时间变化会影响波束控制和自动扫描应用。阵列因子受元件频率和空间分布之间的相干相互作用影响，从而使FDA方向图的空间和时间行为相关联。为了解决这种空间频率相干性问题，伴随空间频率设计算法是控制阵列空间和时间行为的最有效方法。鉴于FDA中阵列因子公式的复杂性，传统上元件的频率和空间分布是分开设计的。然而，本研究提出了一种算法，该算法同时分配元件的位置和频率以实现所需的方向图。对称FDA最初使用通过对称性获得的阵列因子的直接公式进行设计，确保扫描波束稳定且具有周期性。随后，通过分析这些公式，提出了用于扫描应用的两个重要设计参数和几个关键设计标准。这些参数构成了一种设计算法的基础，该算法能够在空间频率平面中同时设计元件位置和频率，从而满足方向图的时间和空间要求。为了证明所提出算法的有效性，设计了两种不同的平面阵列，并将其结果与其他平面配置的结果进行了比较。本研究为频率分集阵列（FDA）的新型设计方法奠定了基础，为阵列设计开辟了新的可能性。
