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分形天线是分形几何和天线技术交叉的产物,分形概念用于天线阵的工程合成,有助于将等幅度面阵和随机面阵的优点结合起来,将分形的自相似特征用于随机面阵设计有助于控制旁瓣区域的天线方向图。基于维尔斯特拉斯(Weierstrass)广义函数,研究天线阵排列系数函数的连续和不可微分的特性,通过对天线阵的分形电动力学和天线阵可实现性条件的研究分析,给出天线阵合成示例,得到Weierstrass不同尺寸天线阵的辐射特性与分形因子的作用关系。指出雷达天线阵列在结构、频带、副瓣等方面需要进行改进。 相似文献
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Thinning of 2D and 3D Fractal Antenna Arrays with Bounded and Unbounded Fractal Distribution Functions for Celestial Communications 下载免费PDF全文
Fractal antenna arrays are geometry‐based thinned arrays having multiband applications. The major challenge of these arrays is their large number of elements at higher expansion factors. This article presents the thinning of fractal antenna arrays while maintaining an appropriate balance between the side lobe level and beam width by using various quantized fractal distribution functions. A 2D square fractal antenna array and 3DSierpinski gasket antenna array are considered in this article to validate the proposed distribution functions. Nearly one third of the antenna elements are thinned in each successive iteration except in the case of a one‐count distribution function. The proposed technique can simplify practical implementation and exhibits better performance for various parameters such as the side lobe level, side lobe angle, and half power beam width than fully populated fractal antenna arrays. 相似文献
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分形天线的特性分析及其在MIMO天线中的应用 总被引:2,自引:0,他引:2
分形最基本的特征是自相似特性与分数维,可以很好地应用于设计天线.与传统天线相比,在性能保持相近的情况下,分形天线表现出两个突出的优势:减小天线尺寸和使天线在多频带下工作.文中以Koch天线、分形树天线和分形环天线为例,说明了分形天线减小天线尺寸的优势;以Sierpinski基垫天线为例,说明了分形天线增加天线工作频带的优势.还对Minkowski分形天线阵列进行了分析,表明作为天线阵列单元的分形天线,可以提高天线阵的辐射特性.文中提出了将Minkowski分形天线应用于多输入输出(MIMO)天线中. 相似文献
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本文讨论了一种关于微带天线阵的设计技术,这种技术可用于设计任意波束指向的梳形微带行波阵。由于采用了行波结构和特殊设计,所以能够获得较宽的频带和较低的副瓣电子。文中给出了两个斜射波束梳形微带行波阵的设计实例,实验表明这种天线具有良好的电特性。 相似文献
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Fractal antenna arrays are usually used to tune multiband frequencies. However, these types of iteratively constructed antennas are associated with undesirable high sidelobe levels and low directivities. In this paper, an optimization procedure based on the genetic algorithm is used to find the optimal weights of the array elements such that the corresponding array patterns have low sidelobe levels and good directivity. Moreover, the fractal nature in the proposed arrays is maintained regardless of the optimized weights. Thus, the proposed fractal-shaped array maintains its capability in performing multiband frequency operation. These good radiation features make the proposed fractal-shaped array more appropriate for the current and future wireless communication applications. Simulation results confirm the superiority of the presented linear and planar fractal-shaped array structures with compared to the conventional fractal cantor linear array and the standard Sierpinski carpet planar array. For the proposed fractal cantor linear array, the sidelobe level has been reduced to more than −20 dB at different operating frequencies, and the directivity has been improved by more than 8 dB, while the modified Sierpinski carpet planar array has achieved −30 dB depressions in the sidelobe level and 6 dB improvement in the directivity. 相似文献
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周子成 《电子信息对抗技术》2012,(2):38-40
介绍了几种常用的阵列方向图综合方法。切比雪夫阵列在指定的副瓣电平下主瓣宽度最窄,在指定的主瓣宽度下副瓣电平最低;相位控制技术通过控制阵列各单元的相位实现波束的指向变化;最后介绍了遗传算法并利用遗传算法优化了8元线阵,将其相对副瓣电平抑制到了-50dB。 相似文献
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本文首先研究了天线时域辐射远场的基本原理,建立了计算公式.在此基础之上,分析了相控阵天线工作在窄脉冲条件下的时域辐射场,发现其时域方向性(如:时域远场峰值方向图、时域远场平均功率方向图)与频域方向性(频域远场方向图)并不一致,这种不一致性随着天线口径的增大或脉冲宽度的变窄而愈加明显,并且在天线注满时间之内表现得尤为突出.文章由此指出:对于超宽带超低副瓣相控阵天线来说,其性能用时域指标去衡量胜于用频域指标去衡量的新观点. 相似文献
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In this letter, we propose a novel design scheme for an optimal non‐uniform planar array geometry in view of maximum side‐lobe reduction. This is implemented by a thinned array using a genetic algorithm. We show that the proposed method can maintain a low side‐lobe level without pattern distortion during beam steering. 相似文献
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An efficient recursive procedure for evaluating the impedance matrix of linear and planar fractal arrays 总被引:1,自引:0,他引:1
Werner D.H. Baldacci D. Werner P.L. 《Antennas and Propagation, IEEE Transactions on》2004,52(2):380-387
The self-similar geometrical properties of fractal arrays are exploited in this paper to develop fast recursive algorithms for efficient evaluation of the associated impedance matrices as well as driving point impedances. The methodology is demonstrated by considering two types of uniformly excited fractal arrays consisting of side-by-side half-wave dipole antenna elements. These examples include a triadic Cantor linear fractal array and a Sierpinski carpet planar fractal array. This class of self-similar antenna arrays become significantly large at higher order stages of growth and utilization of fractal analysis allows the impedance matrix, and hence the driving point impedances, to be obtained much more efficiently than would be possible using conventional analysis techniques. 相似文献
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智能天线可以显著地提高移动通信系统的整体性能,然而,受施工、选址及环保等因素的限制,基站端智能天线采用小型化设计已成为一种趋势。设计了一款8单元(8通道)单极化线形智能天线阵。借助仿真软件,分析了单元间距对天线阵性能及小型化的影响。研究结果表明,在满足设计指标的前提下,单元间距为45 mm的紧凑型等间距线形智能天线阵的增益下降3 dB,半功率主瓣宽度增加了9,横向电尺寸减少31.11%。采用非等间距可以使智能天线阵的第一副瓣电平降低5~7 dB,横向电尺寸减少9.18%~20%。 相似文献
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Rajrup Saha Avishek Das Durbadal Mandal Rajib Kar 《International Journal of Communication Systems》2023,36(17):e5597
This research illustrates a precise linear and elliptical antenna array design for synthesising the optimal far-field radiation pattern in the fifth-generation (5G) communication spectrum using a meta-heuristic optimisation technique known as black widow optimisation (BWO). 5G communication is an emerging technology with revolutionary changes in the wireless communication system with ultra-high data rate, enhanced capacity, low latency and good quality of service. An accurate antenna array design for an ideal far-field radiation pattern synthesis with a suppressed side lobe level (SLL) value and half power beam width (HPBW) is the most crucial aspect of 5G communications. A suppressed SLL is necessary to reduce interference in the entire side lobe region, whereas a low HPBW is required for long-distance communication. Here, the BWO is employed to find the optimal feeding current to each array element to lower the SLL and the HPBW value. The BWO algorithm sustains impeccable equity between the exploration and exploitation stages to impact different potential regions of the search space and generate new solutions to attain the global optima by evading the trap of local optima. The design examples of the linear antenna array (LAA) and elliptical antenna array (EAA) are illustrated in this article by applying the optimal feeding currents to each array element. Compared to the uniform antenna array and methodologies described in the recently published literature, the results obtained utilising the BWO algorithm for designing the LAAs and EAAs demonstrate a substantial development in the reduction of SLL and HPBW. 相似文献
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Md. Moklesur Rahman Heung-Gyoon Ryu 《International Journal of Communication Systems》2023,36(8):e5475
In this paper, in order to improve the received signal strength (RSS) and signal quality, three arrays of electronically steerable parasitic array radiator (ESPAR) antennas are suggested for the ultra-high frequency (UHF) radio frequency identification (RFID) communication and sensing system applications. Instead of the single antenna, the array antennas have recently been widely used in many communication systems because of their peak gains, better radiation patterns, and higher radiation efficiency. Also, there are some important issues to use the antenna array like high data rates in wireless communication systems and to better understand the many targets or sensors. In this article, a wireless sensor network (WSN) is being investigated to overcome multipath fading and interference by antenna nulling technology that can be achieved through beam control ESPAR array antennas. The proposed ESPAR array antennas exhibit higher gains like 9.63, 10.2, and 12 dBi and proper radiation patterns from one array to another. Moreover, we investigate the mutual coupling effect on the performance of array antennas with different spacing (0.5λ, 0.75λ, λ) and configurations. It is found that the worst mutual coupling reduced by −28 to −34 dB for 2 × 2 array, −3 to −43 dB for 2 × 3 array, and finally −42 dB to −51 dB due to the antenna spacing from 0.5λ to λ. Thus, these suggested antennas could effectively be applied in the WSN communication systems, internet of things (IoT) networks, and massive wireless and backscatter communication systems. 相似文献
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针对机载X 波段圆口径相控阵天线,文中提出了五种典型子阵划分方法,以解决相控阵天线瞬时宽带工作时宽角扫描波束色散的难题,同时,实现指向角偏差、第一副瓣电平、增益、平均副瓣电平、最大副瓣电平等典型参数性能最优化;在仿真分析基础上,总结了子阵划分方法与天线性能之间对应关系。 相似文献
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采用2阶皮亚诺分形曲线,设计了一种具有高增益端射特性的微带阵列天线。该阵列天线由多段皮亚诺分形曲线组成,通过添加微带相移器,分形曲线构成了一个偶极子天线阵列。文中介绍和分析了该分形阵列天线的工作原理、结构和主要参数对性能的影响。设计并制作了一只工作于5.8 GHz的分形阵列天线,仿真和测试结果表明,该天线具有良好的辐射特性,其端射增益达19 dB,旁瓣<-12 dB,交叉极化>30 dB,天线口径效率超过90%。 相似文献
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本文提出了一种新颖的极化捷变放大器型有源微带天线阵,只要在馈电端电控单一有源电路就能实现整个微带天线面阵极化的捷变和信号的放大.利用角馈方形微带贴片设计了一副具有高隔离度和低交叉极化的新颖16元双极化面阵,并分析了天线阵的共极化和交叉极化方向图.介绍了有源电路的设计.该电路利用一专用电控移相器,通过改变场效应管(FET)栅极的直流控制电压,电控两极化端口间的0°或90°相差,实现天线阵由线极化到圆极化的捷变.低噪声放大器(LNA)不仅使有源天线增益提高12-14dB,而且改善了天线的驻波比带宽和隔离度.文中给出了无源双极化阵和有源阵的实验结果,证实了理论的有效性. 相似文献