Synthesis of sparse planar antenna arrays with multiple constraints

Synthesis of symmetrical sparse planar antenna arrays is introduced in this paper. In order to reduce the peak sidelobe level of the radiation pattern, the element positions of the arrays are optimized by invasive weed optimization with complex boundary conditions. The proposed algorithm changes a two‐dimensional optimization problem into a linear problem, which will reduce the complexity of the optimization procedure. The optimization method can constrain the size of the array aperture, the element number of the array, and the minimum spacing of the adjacent elements simultaneously. The simulation results show the robustness and effectiveness of the proposed method.     

Optimal array factor radiation pattern synthesis for linear antenna array using cat swarm optimization: validation by an electromagnetic simulator

In this paper, an optimal design of linear antenna arrays having microstrip patch antenna elements has been carried out. Cat swarm optimization (CSO) has been applied for the optimization of the control parameters of radiation pattern of an antenna array. The optimal radiation patterns of isotropic antenna elements are obtained by optimizing the current excitation weight of each element and the inter-element spacing. The antenna arrays of 12, 16, and 20 elements are taken as examples. The arrays are designed by using MATLAB computation and are validated through Computer Simulation Technology-Microwave Studio (CST-MWS). From the simulation results it is evident that CSO is able to yield the optimal design of linear antenna arrays of patch antenna elements.     

An optimal circular antenna array design considering mutual coupling using heuristic approaches

This article shows the design of a non‐uniformly excited single ring circular antenna array (CAA) for the synthesis of optimal far‐field radiation characteristics. A recently proposed meta‐heuristic based optimization algorithm called gray wolf optimization (GWO) and state‐of‐the‐art swarm intelligence based evolutionary optimization technique known as particle swarm optimization with a distribution based update mechanism (PSOd) are individually applied to determine the optimum set of current excitation amplitude weights and the inter‐element spacing among the array elements to reduce the side lobe level and 3‐dB beamwidth considering the mutual coupling. The results obtained by employing PSOd and GWO are compared to those of the uniform radiation pattern and the recently published results of state‐of‐the‐art literature having equal sets of elements to show the superiority of employed approaches. Three different design examples of 8, 10, and 12 elements CAA are reported in this article to study the performances of PSOd and GWO algorithm‐based results over the results of other recently reported literature.     

Optimization of circular antenna arrays using the cuckoo search algorithm

This article presents a study of circular antenna array design and optimization using the cuckoo search (CS) algorithm. The goal of optimization is to minimize the maximum sidelobe level with and without null steering. The CS algorithm is used to determine the parameters of the array elements that produce the desired radiation pattern. We illustrated the effectiveness of the CS in the design and optimization of circular antenna arrays by means of extensive numerical simulations. We compared our results with other methods from the literature whenever possible. We presented numerous examples that show the excellent performance and robustness of the CS algorithm and the results reveal that the design of circular antenna arrays using the CS algorithm provides acceptable enhancement compared with the uniform array or the design obtained using other optimization methods.     

Synthesis of linear antenna array using flower pollination algorithm

Linear antenna array (LAA) design is a classical electromagnetic problem. It has been extensively dealt by number of researchers in the past, and different optimization algorithms have been applied for the synthesis of LAA. This paper presents a relatively new optimization technique, namely flower pollination algorithm (FPA) for the design of LAA for reducing the maximum side lobe level (SLL) and null control. The desired antenna is achieved by controlling only amplitudes or positions of the array elements. FPA is a novel meta-heuristic optimization method based on the process of pollination of flowers. The effectiveness and capability of FPA have been proved by taking difficult instances of antenna array design with single and multiple objectives. It is found that FPA is able to provide SLL reduction and steering the nulls in the undesired interference directions. Numerical results of FPA are also compared with the available results in the literature of state-of-the-art algorithms like genetic algorithm, particle swarm optimization, cuckoo search, tabu search, biogeography based optimization (BBO) and others which also proves the better performance of the proposed method. Moreover, FPA is more consistent in giving optimum results as compared to BBO method reported recently in the literature.

     

增加主瓣增益控制的阵列天线方向图综合遗传算法

阵列天线方向图综合是针对阵列天线方向图进行的相关研究中的一项基础性的研究内容。不同的应用场景中不仅需要设计形式不同的天线阵列,更需要阵列天线方向图并根据不同的性能参数指标要求进行分析优化,从而获得符合使用要求的阵列方向图。针对传统阵列天线方向图综合算法在方向图综合过程中未考虑主瓣增益约束的问题,提出了一种用于阵列天线方向图综合的改进遗传算法。在经典遗传算法的基础上设计了新的适应度函数以满足特殊情况下对主瓣增益进行约束的需求;并在算法计算过程中增加了精英保留策略,设计了随进化代数改变的交叉、变异概率。经仿真实验,结果表明所提算法能够在阵列天线方向图综合时在保证主瓣方向上的增益满足要求的同时可以获得相对低的副瓣电平水平。     

电磁矢量互质阵中基于降维Capon的DOA和极化估计算法

将传统电磁矢量均匀阵列推广为电磁矢量互质阵列,突破了阵元间距不大于半波长的限制。提出了电磁矢量互质阵列中基于降维Capon的波达方向（Direction of arrival,DOA）和极化联合估计算法。该算法无需假设已知极化信息,且只需一维搜索,避免了多维搜索,可实现DOA和极化参数自动配对;与相同阵元数的均匀阵列相比,明显提高了角度估计性能,并拓展了天线孔径,具有相对较高的自由度,且降低了运算复杂度。相同阵列及参数条件下,本文算法的角度估计性能优于ESPRIT算法和三线性分解算法。     

基于遗传算法和禁忌搜索的MIMO雷达天线布阵优化

研究MIMO雷达在发射、接收天线孔径长度和阵元数目固定等约束条件下的天线方向图综合。MIMO雷达采用稀布天线,为了克服栅瓣效应并且降低旁瓣电平,同时为了避免遗传算法早熟收敛,进入局部最优,提出了一种基于遗传算法和禁忌搜索的混合二次优化布阵方法。该方法为了保证系统最大自由度,引入了距离扰动,同时对发射天线和接收天线的位置进行两次优化,有效解决了MIMO雷达天线方向图综合中低旁瓣电平设计问题。仿真结果证明了所提算法的有效性和优越性。     

Application of bacteria foraging algorithm for the design optimization of multi‐objective Yagi‐Uda array

The design of antenna array with desirable multiple performance parameters such as directivity, input impedance, beam width, and side‐lobe level using any optimization algorithm is a highly challenging task. Bacteria Foraging Algorithm (BFA), as reported by electrical engineers, is the most robust and efficient algorithm in comparison with other presently available algorithms for global optimization of multi‐objective, multi‐parameter design problems. The objective of this article is to apply this new optimization technique, BFA, in the design of Yagi‐Uda array for multi‐objective design parameters. We optimize length and spacing for 6 and 15 elements array to achieve higher directivity, pertinent input impedance, minimum 3‐dB beam width, and maximum front to back ratio both in the E and H planes of the array. At first, we develop a Method of Moments code in MATLAB environment for the Yagi‐Uda array structure for obtaining the above design parameters and then coupled with the BFA for the evaluation of the optimized design parameters. Detail simulation results are included to confirm the design criteria. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2010.     

Decoupling antenna array with X‐shaped strip

Manipulating mutual coupling between antenna array elements is always a critical essential in designing phased arrays. In this article, an X‐shaped strip is applied to decouple a five‐element E‐plane microstrip antenna array, whose adjacent elements' center‐to‐center spacing is only 0.45 λ₀. Simulation and measurement results reveal that the proposed array employing the loaded structure exhibits excellent decoupling capability, as in comparison to the reference array, impedance of every port is well matched, mutual coupling between both adjacent elements and nonadjacent ones is efficiently reduced and radiation patterns of every individual patch are markedly corrected. Besides, when beam scanning is performed, the proposed array is equipped with higher gain and lower SLL. The X‐shaped strip predicts a promising application in phased array and a large‐scale array.     

A linear antenna array failure correction using improved bat algorithm

The failure of antenna array elements causes disturbance in the sidelobe power level. In this article, an improved flexible approach that use bat algorithm is proposed and applied to solve the problem of antenna array failure by controlling only the amplitude excitation of array elements. An adaptive inertia weight approach is applied to the standard bat algorithm to improve the quality of the solution and the speed of convergence. The effectiveness of the proposed improved bat algorithm (IBA) is verified on different standard test functions. Numerical examples of element failure correction are presented to show the capability of this flexible approach in antenna array failure correction.     

差分准对立学习多目标蚁狮算法

为解决多目标优化问题，对经典的蚁狮算法进行改进，提出了基于差分进化的准对立学习多目标蚁狮算法（DEQOMALO）。该算法针对蚁狮算法易陷入局部最优的不足，一方面，该算法引用差分进化的思想，充分利用种群和精英蚁狮的信息对原算法中蚂蚁个体的位置更新方式进行改进；另一方面采用反向学习策略对蚂蚁种群进行优化，将原种群个体和其准对立个体进行混合并择优作为新的种群，大大增加种群的多样性。选取典型的标准测试函数，将提出的算法与原始蚁狮算法以及其他传统进化策略优化的蚁狮算法进行比较。实验结果表明，改进算法在收敛性和分布性上均有很大程度的提升，在解决双目标优化问题上具有较好的鲁棒性和有效性。     

基于微遗传算法的稀疏天线阵列优化方法

为生成无栅瓣、高空间分辨率的方向图,均匀平面阵列使用的天线单元数量很多,实现难度和成本高。稀疏布阵只需要相对较少的单元数目,会出现旁瓣电平升高、测向模糊等问题。通过对天线阵列特性进行分析,以全向一致、无栅瓣、低旁瓣的高分辨方向图为目标,利用微遗传算法对多重圆环阵列单元的位置参数进行优化,性能分析表明综合出的多重圆环阵列具有方位角对称、旁瓣电平低、起伏小的特点,且该算法优化效率高、收敛速度快。     

Broadband T‐bar fed slot antenna array with stable horizontally polarized omnidirectional radiation

A broadband horizontally polarized omnidirectional antenna array is proposed, which consists of a circular array of four identical broadband T‐bar fed cavity‐backed slot antenna elements and a 1‐to‐4 power divider. The proposed omnidirectional antenna array has a compact diameter of only 0.44λ₀, a broad bandwidth of 75.9% (450‐1000 MHz) and a favorable omnidirectional radiation pattern in the azimuth plane with a gain variation below 3 dB in the operating band. Moreover, the cavity‐backed structure makes the proposed antenna array hardly affected by metal environment and the all metal construction allows for high‐power applications, and the reserved cable channel behind the cavities of the antenna elements ensures the extensionality and stability of the proposed array when longitudinal array expansion is needed. Design procedures of the proposed antenna array have been described in detail, simulations and measurements of the proposed antenna array have also been carried out to validate its performance in this article.     

基于RSS室内定位中极化敏感圆形阵列研究

针对当前DOA估计中基站布设复杂和阵元间距受限的问题,提出了一种极化敏感圆形阵列单基站定位方法.通过对圆形天线阵列布设进行分析,根据信道传播模型得到阵列接收信号,进而利用深度学习模型实现定位.在考虑电磁波极化特性的基础上,经过对圆形天线的数目以及基站的规模大小进行分析研究,最后给出一种比较理想的基站布设方式.仿真结果表...     

Design of aperiodic planar arrays for isoflux radiation in GEO satellites by applying evolutionary optimization

The design of an aperiodic planar array is presented in this research. This design of aperiodic arrays considers the reduction of the side lobe level and the isoflux radiation requirements for GEO (Geostationary Earth Orbit) satellite applications. In this way, it is considered four different optimization cases. The first two cases are optimizations of amplitude and phase excitations for the antenna elements in a uniform antenna array and the last two cases are optimizations of positions of the antenna elements and certain number of levels of amplitude excitation in an aperiodic array. In this case, it is proposed a simple new approach combining the main idea of both thinned theory and random arrays approaches. For this optimization problem, the well-known method of Genetic Algorithms (GA) is utilized. The obtained results show the proper performance of the array factor to provide the isoflux radiation and low side lobe level. Depending on the performance requirements, the design of the aperiodic array could lead the satellite hardware to be reduced significantly even more that results presented previously in the literature.     

Bit error rate reduction for circular ultrawideband antenna by dynamic differential evolution

The dynamic differential evolution (DDE) is used to synthesize the radiation pattern of the directional circular arc array to minimize the bit error rate (BER) performance in indoor ultrawideband (UWB) communication system. Using the impulse response of multipath channel, the BER performance of the synthesized antenna pattern on binary pulse amplitude modulation system can be calculated. Based on the topography of the circular antenna array and the BER formula, the array pattern synthesis problem can be reformulated into an optimization problem and solved by the DDE algorithm. The novelties of our approach are not only choosing BER as the object function instead of sidelobe level of the antenna pattern but also considering the antenna feed length effect of each array element. The strong point of the DDE algorithm is that it can find out the solution even if the performance index cannot be formulated by simple equations. Simulation results show that the synthesized antenna array pattern is effective to focus maximum gain to the line of site path which scales as the number of array elements. In other words, the receiver can increase the received signal energy to noise ratio. The synthesized array pattern also can mitigate severe multipath fading in complex propagation environment. As a result, the BER can be reduced substantially in indoor UWB communication system. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2012.     

Differential evolution to synthesize low sidelobe thinned isophoric time‐modulated planar array with increased directivity

In this article, a novel method for synthesizing rectangular planar array through thinning and time‐modulation is proposed. A new differential evolution based approach that generates a rank based population is adopted to find out the optimum element off position for thinning and ontime duration to modulate the antenna elements in time domain. The proposed synthesis method defines a preservative boundary at the array center where the antenna elements are not thinned and time‐modulated rather uniformly excited. It is shown that this proposed thinning and time‐modulation strategy with an optimum preservative boundary helps to realize low side lobe radiation pattern with increased directivity by controlling less number of optimization variables as compared to traditional approach. It also reduces the feed network complexity specifically for large antenna arrays.     

Evolutionary optimization of Haferman carpet fractal patterned antenna array

This article investigates radiation characteristics of a new type of fractal shaped antenna array based on Haferman carpet geometry. An iterative feed matrix eases the complexity of array factor calculation that makes the array factor suitable for the application of any evolutionary optimization techniques. It is seen that Haferman carpet array produces peak side lobe level (PSLL) better than Sierpinski carpet that produces ?10 dB PSLL at every stage of growth. Optimization techniques have been applied for array element reduction and PSLL minimization at different stages of growth. Here, PSLL is minimized by turning off array elements and also by varying inter element spacing between the array elements. The optimized version of Haferman carpet array produces better characteristics (49.38% thinning with ?20.5 dB PSLL for stage‐2, 46.3% thinning with ?22 dB PSLL for stage‐3 and 42.3% thinning with ?21dB PSLL for stage‐4) than its original counterpart in terms of reduced element count and PSLL. Numerical results for obtaining optimized array performance exploit both DE as well as PSO. A comparative study on the performance is also presented. As a whole, Haferman carpet is seen to be more effective approach than Sierpinski carpet in fractal antenna paradigm. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:719–729, 2015.     

干涉式微波辐射计成像算法以及天线阵采样方案分析

对旋转扫描干涉式微波辐射计成像算法进行研究,提出了基于伪极网格傅立叶变换的成像算法,利用一维插值以及一维FFT即可实现图像重建,既提高了成像精度,又保证了成像速度。以3种8单元天线排列方案阵为例,利用本文方法和基于线性插值的笛卡儿网格方法分别进行成像模拟,模拟结果验证了本文方法的优越性,同时表明天线阵排列方案对成像结果影响很大,天线阵基线均匀性越好,数量越多,成像质量就越好。直线阵无法实现基线数量与均匀性的统一,而平面阵可以在较好均匀性情况下实现最多的基线数,是天线阵排列的首选方案。