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This study presents a novel optimization method based on the sand cat swarm optimization (SCSO) algorithm for the pattern synthesis of linear antenna-array (LAA), aiming to obtain the high gain and low sidelobe level (SLL). The innovation of the proposed method consists in efficiently regulating the radiation characteristics of the LAA by optimizing the geometric and electrical parameters including the phase, amplitude, rotation and position based on the SCSO algorithm to achieve the desired radiation performances. The full-wave method of moments (MoM) is adopted to rigorously consider the mutual coupling effect among the array elements to guarantee the design accuracy. To demonstrate the feasibility and effectiveness of the SCSO algorithm, the proposed method is compared with three typical algorithms, including the Genetic Algorithm (GA), the Gray Wolf (GWO) algorithm, and the Particle Swarm Optimization (PSO). The results show that the SCSO algorithm demonstrates superior convergence capabilities while maintaining the high gain and low SLL, highlighting the potential as a robust method for the LAA. [ABSTRACT FROM AUTHOR]

In this paper, we develop a new algorithm for pattern synthesis of large linear arrays. In our algorithm, the large linear array is divided into multiple disjoint nonuniformly-spaced subarrays and is only weighted at subarray level. Unlike the existing methods, the subarray synthesis is implemented in two stages. Firstly, the optimization of subarray partition and subarray weights are performed by using the K-means approach. Based on the determined subarray partition and subarray weights, the subarray element positions are further optimized by the iterative convex programming method. Compared with the state-of-the-art methods, the proposed algorithm can synthesize lower peak sidelobe level and yield smaller pattern matching error. Numerical results demonstrate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

This paper proposes a gradient-based optimization method for pattern synthesis of phase-only thinned concentric elliptical antenna arrays (CEAAs) with the tangent interpolation function of continuous 0–1 differentiation in topology optimization. The optimization model is reasonably constructed and actualized by simultaneously optimizing the presence or absence of metal materials and the excitation phase within each array element. In order to facilitate solving the optimization problem using the gradient-based algorithms and performing the CEAA pattern synthesis, the tangent interpolation function of metal material with a pseudo-resistance is introduced to realize the continuous 0–1 differentiation of each array element. The design objective is to maximize the difference between the radiation energies of the main-beam direction and the peak sidelobe level with the constraints on the total number of remaining elements. For ensuring that the mutual coupling between the elements is accurately considered, the full-wave method of moments (MoM) is integrated into the optimization method to synthesize the array radiation pattern. Typical examples are provided to verify the effectiveness of the proposed method. Compared with the uniform array and the reference CEAA, the proposed method not only achieves the sidelobe suppression and aperture reduction but also significantly decreases the total number of array elements. [ABSTRACT FROM AUTHOR]

Irregular phased arrays have recently attracted a lot of interest. In this paper, we propose a novel algorithm for synthesizing the irregular phased array based on subarray partition. The proposed algorithm is implemented in two stages. In the first stage, a shaped flat-top pattern within scanning range is synthesized via convex programming, and the reference excitations are also determined. In the second stage, an adjacent element search algorithm based on excitation match principle is utilized to obtain the subarray tilling configuration and the high-directivity pattern is finally achieved through convex programming. Compared with the existing techniques, the proposed algorithm can obtain the subarray locations more rapidly and yield a pattern with higher directivity under the same peak sidelobe level. Numerical results demonstrate the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, we devise a new hybrid method for pattern synthesis of large linear arrays. To simplify the beamforming network, the uniform linear array is divided into multiple non-overlapped subarrays with contiguous elements and is only weighted at subarrays. Unlike previous approaches, the proposed method introduces a special vector to specify the subarray partition and converts the subarray pattern synthesis to the problem of finding the optimal subarray partition and subarray weighting vectors simultaneously. To solve this problem efficiently, the genetic algorithm is utilized to find the optimal partition scheme from all possible subarray partitions. For the fixed subarray partition, the optimal subarray weighting vector is obtained by solving the convex sub-problem. Numerical results demonstrate the superiority of our method over the state-of-the-art algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new amplitude-only method for pattern synthesis of uniform linear array (ULA) based on genetic algorithm (GA) and artificial neural network (ANN), which can produce a low sidelobe pattern with deep nulls. Unlike existing schemes for pattern synthesis, our method can avoid falling into local optimum and exhibits a faster convergence speed, and is also easy to implement due to its low computational complexity. In complicated and changing environments, the proposed method can quickly and accurately synthesize the desired pattern of the ULA. Numerical results demonstrate the effectiveness of the devised algorithm. [ABSTRACT FROM AUTHOR]

Due to the production and installation error of the antenna array, there is mismatch between the actual array manifold and the ideal. Considering a practical conformal hydrophone array and the shielding of the sonar platform, the isotropy directivity of each sensor may be destroyed seriously, which is a big challenge to beam pattern synthesis. The method of measuring the actual array manifold was proposed, and second-order cone programming (SOCP) was applied to optimize the weights vector of the array sensors. The experiment result shows the irregular directivity of the array sensors. The weights vector was obtained from the measured array manifold and SOCP, and the synthesized beam pattern met the engineering requirements. [ABSTRACT FROM AUTHOR]

Unit circle representation techniques such as Schelkunoff null placement method have been extensively used to synthesize uniformly spaced linear arrays. In this work, it is attempted to extend the unit circle representation approach to synthesize nonuniformly spaced linear arrays with some desired null directions and minimum achievable sidelobe level. The problem is formulated as an optimization task upon which Taguchi method is employed to solve for the set of element positions. Illustrative examples are included to demonstrate the design effectiveness and flexibility for modern wireless communication system applications. [ABSTRACT FROM AUTHOR]

In this paper, Taguchi method, which is a relatively novel optimization technique, is employed. Based on the concept of the orthogonal array, Taguchi method effectively reduces the number of tests required in an optimization process. This method has been successfully applied in many fields such as chemical engineering, mechanical engineering, IC manufacturing, power electronics, etc. In this work, the Taguchi method is applied to optimize linear array antennas for null placement and sidelobe level reduction. The optimization process is carried out by controlling the array parameters including specifically the element excitations (amplitude and phase) and positions. [ABSTRACT FROM AUTHOR]

In this work, a linear phased array pattern design with null steering is achieved using the array polynomial technique and the Particle Swarm Optimization (PSO) algorithm. The null steering for interference suppression is obtained by controlling some of the roots on the Schelkunoff's unit circle while keeping the roots responsible for the main beam unchanged. The rest of the roots are controlled to minimize the Side Lobe Level (SLL) of the array pattern using the PSO algorithm. It has been demonstrated that this technique achieved more than 50% reduction in the parameters needed to be optimized compared with the conventional complex coefficients optimization techniques. Consequently, the fitness function is only responsible for the SLL as the prescribed controlled nulls and the mainbeam characteristics are solved analytically. The simulated results show the effectiveness of the proposed technique. [ABSTRACT FROM AUTHOR]

A method based on the bacterial foraging algorithm (BFA) for the pattern synthesis of linear antenna arrays with the prescribed nulls is presented. Nulling of the pattern is achieved by controlling only the element positions. The BFA is a new evolutionary computing technique, based on the foraging behavior of Escherichia ( E) coli bacteria in a human intestine. Simulation results for Chebyshev patterns with the imposed single, multiple and broad nulls are given to show the effectiveness of the proposed method. For practical consideration, due to small variations of the element positions, the sensitivity of the produced patterns is also examined by rounding the element position values to the second decimal position. [ABSTRACT FROM AUTHOR]

weighted thinned linear array with pattern reconfigurable antenna elements is proposed to overcome the disadvantages of traditional millimeter wave phased arrays, such as, narrow scanning range, high grating lobes. The developed array can scan its main beam from φ = -76° to 76° in H-plane and has 3 dB beam coverage from φ = -88° to 88° with low grating lobes by shifting two operating states of the elements and adjusting the feed phases. [ABSTRACT FROM AUTHOR]

A planar array antenna with arbitrary geometry synthesis technique based on genetic algorithm is discussed. This approach avoids coding/decoding and directly works with complex numbers to simplify computing program and to speed up computation. This approach uses two crossover operators that can overcome premature convergence and the dependence of convergence on initial population. Simulation results show that this method is capable of synthesizing complex pattern shapes of planar arrays with arbitrary geometry and can realize good sidelobe suppression at the same time. [ABSTRACT FROM AUTHOR]

In this paper, an effective system for synthesizing animal skin patterns on arbitrary polygonal surfaces is developed. To accomplish the task, a system inspired by the Clonal Mosaic (CM) model is proposed. The CM model simulates cells’ reactions on arbitrary surface. By controlling the division, mutation and repulsion of cells, a regulated spatial arrangement of cells is formed. This arrangement of cells shows appealing result, which is comparable with those natural patterns observed from animal skin. However, a typical CM simulation process incurs high computational cost, where the distances among cells across a polygonal surface are measured and the movements of cells are constrained on the surface. In this framework, an approach is proposed to transform each of the original 3D geometrical planes of the surface into its Canonical Reference Plane Structure. This structure helps to simplify a 3D computational problem into a more manageable 2D problem. Furthermore, the concept of Local Relaxation is developed to optimally enhance the relaxation process for a typical CM simulation. The performances of the proposed solution methods have been verified with extensive experimental results. [ABSTRACT FROM AUTHOR]

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Pattern synthesis of non-uniform elliptical antenna arrays is presented in this paper. Only the element positions of the antenna arrays are optimized by the combination of differential evolution (DE) and invasive weed optimization (IWO) to reduce the peak side lobe level (PSLL) of the radiation pattern. In order to avoid the overlap of the array elements, the minimum spacing of the adjacent elements is constrained. Also, the beam width of the radiation pattern can be constrained effectively. Three elliptical antenna arrays that have 8, 12, and 20 elements are investigated. The synthesis results show that the introduced method can present a good side lobe reduction for the radiation pattern. Compared with other optimization methods, the method proposed in this paper can obtain better performance. [ABSTRACT FROM AUTHOR]