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.     

遗传算法在阵列天线方向图综合中的应用

应用实数编码的遗传算法进行阵列天线方向图综合的优化设计.针对阵列天线方向图综合的特点,运用算法,通过优化单元电流幅度、阵元间距,对阵列天线方向图进行了综合优化,其中包括方向图的波瓣控制和零点生成,并同时压低旁瓣电平使其达到期望值.仿真结果表明,通过优化,天线阵的辐射特性获得很大的改善,在主瓣宽度满足要求的情况下,副瓣电平也可达到-33.6100dB.良好的仿真结果表明遗传算法在阵列天线方向图综合中的应用是有效的,有良好的应用前景.     

Millimeter‐wave planar high gain SIW antenna using half elliptic radiation slots

This article reports a high gain millimeter‐wave substrate integrated waveguide (SIW) antenna using low cost printed circuit board technology. The half elliptic slots which can provide small shunt admittance, low cross polarization level and low mutual coupling are etched on the board surface of SIW as radiation slots for large array application. Design procedure for analyzing the characteristics of proposed radiation slot, the beam‐forming structure and the array antenna are presented. As examples, an 8 × 8 and a 32 × 32 SIW slot array antennas are designed and verified by experiments. Good agreements between simulation and measured results are achieved, which shows the 8 × 8 SIW slot array antenna has a gain of 20.8 dBi at 42.5 GHz, the maximum sidelobe level of 42.5 GHz E‐plane and H‐plane radiation patterns are 22.3 dB and 22.1 dB, respectively. The 32 × 32 SIW slot array antenna has a maximum measured gain of 30.05 dBi at 42.5 GHz. At 42.3 GHz, the measured antenna has a gain of 29.6 dBi and a maximum sidelobe level of 19.89 dB and 15.0 dB for the E‐plane and H‐plane radiation patterns. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:709–718, 2015.     

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.     

基于遗传算法的深空探测天线综合

为了改善深空探测中共焦面阵列馈电抛物反射面天线的可视范围,提出一种基于遗传算法的扫描波束综合方法。基于物理光学法计算共焦面馈电阵中每个馈源照射反射面的次级远场方向图,利用遗传算法优化得到的权值对各次级方向图加权合成期望的波束。仿真和分析结果表明：提出的基于遗传算法的共焦面阵列馈电反射面方向图综合与传统共轭场匹配方法相比,可控制旁瓣电平,更精确综合出期望方向图,扩大深空探测天线的可视范围。     

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。     

Design of transmittarray feed by filtering dielectric antenna for 5G

In this article, a high gain transmittarray antenna for 5G is presented. The transmittarray antenna is composed of an ultra‐thin transmitarray and its feed structure of the filtering dielectric antenna. The ultra‐thin transmitarray based on cross‐shaped metasurface is designed to realize the gradient distribution of phase covering the range of 0~2 π. The compact low temperature co‐fired ceramic dielctric antenna array feed by subtrate integrated waveguide powder divider is exploited as the feed of the transmittarray. The experimental results show the metasurface of the structure has obvious convergence effect on the radiation energy of the antenna, and the directivity of the antenna is greatly enhanced. The sidelobe energy is effectively suppressed and the peak gain of the antenna is increased from 11.47 dB to 22.8 dB at the central frequency of 28.0 GHz. The high gain and small size make the transmittarray antenna suitable for application in 5G wireless communication.     

Low-sidelobe marine radar microstrip array antenna based on hybrid algorithm and metamaterial

A microstrip array antenna with low sidelobe level (SLL) for X-band marine radar is proposed. The antenna is composed of a 32-element patch array and a three-layer near-zero-index metamaterial (NZIM). The IABC-Kmeans algorithm, which combines the improved artificial bee colony algorithm and K-means clustering algorithm, is used to optimize the current amplitude of the array elements to obtain a lower SLL. The NZIM is loaded in front of the array antenna to reduce the beamwidth of the E-plane. The antenna is designed and fabricated. The measurement results show that the gain of the antenna at the center frequency is 22.7 dBi, the SLLs of H-plane and E-plane are ?30.66 dB and ? 26.78 dB respectively, and the half-power beamwidth of H-plane is 5.9°. Compared with the previous similar antenna structures, the antenna has lower SLL under the premise of narrow beam and high gain, which is very suitable for X-band marine radar of small and medium fishing vessels.     

Planar circularly polarized X‐band array antenna with low sidelobe and high aperture efficiency for small satellites

A planar broadband circularly polarized (CP) X‐band array antenna with low sidelobe and high aperture efficiency is presented for small satellite applications. The array design is composed of 4 × 4 broadband CP stacked patch elements, which are fed by a feeding network consisted of unequal series‐parallel power dividers to achieve the low sidelobe and high aperture efficiency. The final prototype with overall size of 100 mm × 100 mm × 3 mm (2.73λ₀ × 2.73λ₀ × 0.082λ₀ at 8.2 GHz) was fabricated and measured. The antenna has a broadband characteristic with |S₁₁| < ?10 dB bandwidth of 15.9% (7.52‐8.82 GHz) and 3‐dB axial ratio bandwidth of 11.95% (7.63‐8.60 GHz). Also, it achieves an excellent broadside CP radiation with a gain of 17.2‐20.03 dBic, a sidelobe level of <?20 dB, and aperture efficiency of 65% to 97.5%. With these features, the proposed antenna is a good candidate for high‐speed data downlink onboard small satellites (MiniSat, MicroSat, NanoSat, and CubeSat).     

基于改进遗传算法的圆阵稀布方法

由于圆形阵列所具有的特性,使其正得到日益广泛的应用,但是圆阵方向图却具有相对主瓣较高的旁瓣电平。为此,针对稀布圆形阵列的天线单元使旁瓣电平尽量降低的问题,应用改进的遗传算法,取角度差值为染色体的基因,进行阵列孔径、单元个数、最小间隔一定的稀布优化排列,减小了遗传算法的搜索空间,提高了搜索效率。仿真结果表明:该方法能有效提高收敛速度、降低圆阵的旁瓣电平。     

Gain enhancement for low cost planar reflectarray antenna using hybrid elements

By using a hybrid configuration of reflective elements of at least two different types, the gain of a planar reflectarray antenna is successfully enhanced. According to the calculated phase‐shift distribution, the reflecting surface is covered mainly by traditional low‐loss element such as square patches (SPs) in the first. Then the blank cells, of which the required phase‐shift exceed the operational range of the SP, are covered by other elements having large phase‐shift, for example, the three‐ring patches. As a result, the antenna efficiency is kept in a high level because the low loss elements are in majority. Meanwhile, the main beam efficiency is kept high because the sidelobe level is suppressed by large phase‐shift elements. For verification, an experimental array is fabricated on an inversely suspended, low cost FR4 substrate. The simulated result shows that the sample antenna is advanced in high gain and low sidelobe level, comparing with its traditional counterparts with only one type reflectarray elements. The measured result agrees well with the simulations, which show the gain of the antenna is higher than 26 dB, while the sidelobe suppression is lower than ?19 dB. The aperture efficiency reaches about 47.04% at 14.0 GHz, which achieves the performance of high‐cost reflectarray antenna.     

MIMO‐UWB smart antenna communication characteristics for different antenna arrays of transmitters

The channel capacity of indoor multiple‐input multiple‐output ultra‐wide band (MIMO‐UWB) transmission for smart antenna is presented. The genetic algorithm (GA) is used to synthesize the radiation pattern of the directional antenna array to maximize the capacity performance in indoor MIMO‐UWB communication system. Three types of antenna arrays such as circular shape, L shape and Y shape arrays are used in the transmitter and their corresponding capacity on several paths in the indoor environment are calculated. The UWB impulse responses of the indoor channel for any transmitter‐receiver location are computed by applying shooting and bouncing ray/image (SBR/image) techniques, inverse fast Fourier transform and Hermitian processing. By using the calculated frequency response, the capacity performance of the synthesized antenna pattern on MIMO‐UWB system can be computed. Based on the topography of the antenna array and the capacity formula, the array pattern synthesis problem can be reformulated into an optimization problem and solved by the GA algorithm. The GA algorithm optimization is applied to a high order nonlinear optimization problem. The novelties of our approach is not only choosing capacity as the cost function instead of sidelobe level of the antenna pattern, but also considering the antenna feed length effect of each array element. The cost function for the problem is nonsmooth and discontinuous with respect to the antenna pattern. It is difficult to solve by gradient methods, since the derivative is hard to derive. The GA algorithm is employed to optimize the excitation voltages and feed lengths for these antenna arrays to increase the capacity. The strong point of the GA is that it can find out the solution even if the performance index cannot be formulated by simple equations. Numerical results show that the synthesized antenna array pattern is effective to focus maximum gain to the LOS path for these antenna arrays. 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 capacity can be increased substantially in indoor MIMO‐UWB communication system. The investigated results can help communication engineers improve their planning and design of indoor wireless communication. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

基于遗传算法的圆柱阵列稀疏方法

由于共形阵列所具有的特性,使其正得到日益广泛的应用,但其耗用较多的阵元,方向图具有相对主瓣较高的旁瓣电平。为此,针对基本的共形阵列——圆柱阵列的天线阵元,应用经典遗传算法,以阵元的工作状态为优化参量,对其进行稀疏。减少了阵元数量,仿真结果表明,该方法能有效地降低圆柱阵列的旁瓣电平。     

Development of an Enhanced Ant Lion Optimization Algorithm and its Application in Antenna Array Synthesis

In order to design a highly effective communication system, antenna plays a vital role and antenna array adds to the performances. And to achieve such a goal, the crucial challenge is to determine the optimum spacing between the elements and their excitations. In order to address this issue a novel optimization technique named as enhanced ant lion optimization (e-ALO) algorithm has been developed by modifying the basic Ant lion optimization algorithm. Further, to validate the efficacy of the proposed algorithm, few benchmark functions have been successfully tested and significant improvement is obtained in comparison to other reported optimization approaches. The proposed scheme is applied to antenna array synthesis problem to optimize the inter-element spacing and excitation of the elements for different antenna geometries, with an objective to minimize the sidelobe levels while keeping other constraints within boundary limits. The encouraging results obtained from the study have emphatically placed the proposed e-ALO algorithm in the optimization arena as a dominant player.     

汽车雷达微带阵列天线设计

为提高汽车雷达性能,设计了一款汽车雷达天线,采用4×8微带阵列天线形式,设计中心频率为24.1 GHz,采用指数加权的方式设计馈电网络,以降低副瓣.在HFSS电磁仿真平台上对其进行仿真、优化.仿真结果显示天线最大增益为21.4 dBi,副瓣电平低于-15 dB,H面半功率波束宽度约为10°,在24 ～ 24.5 GHz频段性能稳定.天线整体长约70 mm,宽约36 mm,体积小.将该天线应用于汽车雷达可以探测车辆和障碍物的速度、距离、角度等信息,从而实现防撞预警、盲点侦测等功能.     

A K/Ka‐band dielectric and metallic 3D printed aperture shared multibeam parabolic reflector antenna for satellite communication

A K/Ka‐band (22‐33 GHz) high‐gain aperture shared multibeam parabolic reflector antenna is proposed. It performs a two‐dimensional beam scanning from a shared single parabolic reflector by introducing off‐focal feeds. The feed array is placed on and off the focal of the parabolic reflector. Traditionally, the feed blockage has a great impact on the performance of the antenna, which reduces the gain and increases the sidelobe level. The purpose of this paper is to suppress the negative effects of feed blockage by using hybrid material processing method. Both dielectric and metallic 3D printing technologies are used for antenna fabrication. The parabolic reflector antenna is printed by selective laser melting using aluminum alloy. The feed array and the supporting structures are printed by stereolithography apparatus in resin to control the blockage. The method helps to suppress the sidelobe level from ?10 to ?15 dB and to enhance gain by up to 2.3 dBi. The reflection coefficient is less than ?10 dB, while the coupling coefficient between the ports is less than ?20 dB over the entire designed band. At 31.5 GHz, the simulated maximum gain of the antenna are 30.7, 29.1, and 29.7 dBi, when different port separately excites. Multiple beams at ±15° and 0° are observed on both E‐ and H‐planes. Besides, it also verifies the possibility to use dielectric and metallic 3D printing technologies in hybrid for microwave device fabrication.     

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.     

Efficient design of compact millimeter wave microstrip linear array with bandwidth enhancement and sidelobe reduction

In this article, a novel linear mmWave antenna array with series‐feed network is proposed to enhance the bandwidth and reduce sidelobe level without increasing the patch size. The proposed linear array is consisted of four identical wideband array elements, which are all under operation TM₁₀ and TM₀₂ modes by loading shorting pin and rectangular slots. Additionally, through loading symmetry circle‐shaped slots for the four elements, impedance matching of linear array is achieved. Furthermore, multi‐parameters unified‐optimization (MPUO) based on imperial competition algorithm (ICA) is proposed to uniformly optimize all linear array parameters. To verify this design, the proposed linear array is fabricated with a small patch area of 7.5 × 3.914 × 0.254 mm³. The measured results show that the bandwidth is enhanced to 2.05GHz, which is 0.57GHz wider than that of simulation. The simulated peak gain reaches 13dBi while the sidelobe level is reduced to about ?19 dB at 28.6GHz. Moreover, the computation cost using MPUO is reduced by 98.12% compared with that of independent parameters optimization.     

Development of phased array antenna by controlling the filling factor of periodic structure

A phased array antenna is realized by utilizing the variation of filling factor (FF) of electromagnetic bandgap (EBG) structures. The variation takes place under the feed line of a 4‐element array that gives the change in relative phase shift. The phase shift achieved from different combinations of EBGS lying under the feed lines is used in personal computer aided antenna design software, PCAAD 4.0, to see the beam steering capacity. Then the same feed lines are connected with four microstrip patches to yield a 4‐elements phased array antenna. The 4‐elements phased array antenna is simulated in electromagnetic (EM) software Zeland IE3D. Finally, the design is fabricated with the help of milling machine that takes the help of ISOPRO and QUICKCAM software. It can be seen that the beam steering angle increases with the increase of FFs. Thus a novel FF of EBGS based phased array antenna is developed. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Investigations on low sidelobe characteristics of reflectarray antenna for W‐band wireless sensor application

A W‐band low sidelobe level offset‐fed reflectarray antenna is designed, fabricated, and measured. Compared to conventional offset‐fed reflectarray antenna, the sidelobe level of proposed one is decreased significantly when the inclination angle of reflector is half of the incident angle of the feeding. At the same time, a large‐radiation‐area element is used to obtain low sidelobe level for the offset‐fed reflectarray antenna because of its large radiating element area and low specular reflection. A 52 mm× 180 mm offset‐fed reflector antenna have been designed and measured to verify the availability. From 90 to 96 GHz, measured results show that a maximum gain of 36dBi at 93 GHz, and the peak sidelobe level of 18dBc can be obtained with the proposed architecture.