Mohammed, Jafar Ramadhan

Sayidmarie, Khalil H.

English

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Introductory Chapter: Introduction to Array Pattern Optimization

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Selection of our books indexed in the Book Citation Index in Web of Science™ Core Collection (BKCI)Interested in publishing with us? Contact book.department@intechopen.comNumbers displayed above are based on latest data collected. For more information visit www.intechopen.comOpen access books availableCountries delivered to Contributors from top 500 universitiesInternational  authors and editorsOur authors are among themost cited scientistsDownloadsWe are IntechOpen,the world’s leading publisher ofOpen Access booksBuilt by scientists, for scientists12.2%122,000 135MTOP 1%1544,8001ChapterIntroductory Chapter: Introduction to Array Pattern OptimizationKhalil H. Sayidmarie and Jafar Ramadhan MohammedArray antennas offer versatile and flexible solutions to the requirement for desired radiation patterns. The total field of the array can be controlled by five array parameters that are the main design parameters [1]. These are: the geometrical layout of the array elements and their spacings, the excitation amplitude and phase of the individual elements, and finally the pattern of the individual elements. These factors have been utilized by many array synthesis techniques that use either analytical or numerical approaches. These techniques have been extensively studied and are well documented [2, 3]. This chapter aims at presenting recent techniques that aim to improve and optimize the radiation pattern of array antennas.While most of the array pattern synthesis approaches deal with all of the elements of the array antenna, the techniques presented in Chapter 2 offer easier solutions as only a limited number of the elements need to have their magnitudes and phases adjusted. Such approaches reduce the cost and complexity of the optimization process and achieve the desired radiation patterns by modifying the excitations of a small number of elements. Toward achieving this goal, earlier techniques that were based on simple analytical procedures have utilized only two or four elements at the side of the array to reduce the sidelobe level [4–9]. These simple analytical approaches have demonstrated the feasibility of the techniques in finding the proper excitations of the side elements. The same idea was developed to the case of planar arrays where much larger number of elements is used and much less number of controllable elements was required. Thus, it would be more economical if only the side elements are made controllable for the improvement of the array pattern [10]. The deployment of the side elements was also found applicable to improve the sum and difference patterns [11]. Some other effective methods based on either controlling the steer angle in a certain sub-array configuration or even sharing the element excitations at the tail of the array were also used to generate an improved sum and difference patterns in the tracking antenna arrays [12, 13]. The use of the side elements for obtaining a wide-angle null in the radiation pattern was presented in [14, 15]. Other approaches have utilized few elements at the center of the array to achieve better adaptive responses [16]. The side element idea was also deployed for the synthesis of asymmetrical radiation pattern where it is desirable to highly reduce the sidelobe on one side of the main beam while tolerating a higher sidelobes on the other side [17].While simple analytical approaches give better insight into the mechanism of the antenna pattern improvement, global numerical optimization methods have been proved to give better performance and optimum results [18–20] than those analytical approaches. In order to show the superiority and the power of the global optimization methods that were presented in [18–20] among the analytical approaches that were Array Pattern Optimization2presented in [10, 15], the nonsymmetric array is considered as an example. For this case, the mathematical equation of the array factor with two variable parameters on each side of the array cannot be solved analytically using the method introduced in [15], since it is a function of four unknown parameters, that is, two different attenu-ators and two different phase shifters. However, this case can be efficiently solved, and optimal values of the unknown parameters in the array factor can be easily found using any global optimization algorithm such as genetic algorithm or particle swarm optimization (PSO) as it was shown in [18–20]. On the other hand, the analytical approaches [10, 15] were able to solve this case only under the assumption of symmet-ric array and by assuming a proper value of the required phase shifter and then find the value of unknown parameter of the required amplitude excitation. However, the symmetric array is not a general case especially in practice.Most of the designs dealing with array antennas, as those described in Chapter 2, are concerned with the radiation pattern in the farfield region at a constant distance or equivalently across the surface of a sphere. In some applications, the designed array antenna is required to supply field or power density distribution of certain characteristics across a plane surface. This goal can be approached through one of the synthesis techniques. The problem of antenna array synthesis for radiation pattern defined on a planar surface is examined in Chapter 3. In this situation, the distance from the array to the planar surface cannot be assumed constant, and thus the 1/r decay factor effect cannot be neglected. One example of such case is an antenna array that is mechanically tilted and a pattern defined in terms of Cartesian coordinates, as in the electronic toll collection (ETC) scenario [21]. In this application, the plane surface is parallel to and just above the ground, while the transmitting and receiving antennas are a few meters above the ground. Chapter 3 presents two possible approaches to this issue [22, 23]. The first one aims at the precise synthesis of the pattern in the case both a constant power bounded area and a sidelobe suppression region are defined and the required element excitations need to be found. In the second approach, the coverage area is stretched toward the travel length (without considering a precise definition of the communication area). This is to increase the available identification time with an iterative methodology. The chapter presents an antenna prototype which was fabricated and experimentally tested to confirm the validity of the approach [24].An important approach to the design and optimization of array patterns is the beamforming techniques. Here, the array elements are fed through a network that furnishes the phases and magnitudes necessary to obtain the desired radia-tion pattern. Chapter 4 reviews the worldwide progress in the design of optical beamforming networks that are intended to the next-generation ultra-wideband millimeter-wave phased array antennas [25, 26]. Such approaches are prepared for the incoming 5G wireless systems, which in recent years are under investigation and development of worldwide communication community. Toward this goal, the chapter presents a detailed study for the design concepts below true-time delay pho-tonics beamforming networks based on switchable or continuously tunable control. The NI AWRDE CAD-based simulation experiments are presented in the frequency range of 57–76 GHz on design of two 16-channel photonics beamforming networks using true time delay approach [27]. In the first scheme of the known configuration, each channel includes laser, optical modulator, and 5-bit binary switchable chain of optical delay lines. The second scheme has an optimized configuration based on only 3-bit binary switchable chain of optical delay lines in each channel, all of which are driven by four lasers with wavelength division multiplexing and a common opti-cal modulator. In the result, the novel structurally and cost-efficient configuration of microwave-photonics beamforming network combining wavelength division multiplexing and true time delay techniques is proposed and investigated.3© 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Introductory Chapter: Introduction to Array Pattern OptimizationDOI: http://dx.doi.org/10.5772/intechopen.83596Author detailsKhalil H. Sayidmarie and Jafar Ramadhan Mohammed*College of Electronic Engineering, Ninevah University, Mosul, Iraq*Address all correspondence to: jafarram@yahoo.comAs the applications of the array antenna principles are developing, the number of the required antenna elements is rapidly increasing, as for the case of scanned radars and synthetic imaging radars. In compliance with the development of  massive  multiple-input multiple-output (MIMO) and beamforming techniques in 5G technology increased antenna elements became of further concern. The integrated antenna, which is composed of multiple antenna elements, will be considered for next  generation technologies. Therefore, chapter 5 provides the mathematical and practi-cal explanation of the integrated antenna for the next generation technologies. The integrated antenna array consists of multiple array elements, and the array element has multiple antenna elements. Each antenna element of the integrated antenna has different radiation patterns to increase the spectral efficiency in wireless commu-nication area. This chapter first presents a mathematical expression of the antenna element based on the spherical vector wave modes [28], then the channel models for the integrated antenna, and the antenna array based on the integrated antenna are explained. Second, the chapter provides practical antennas designed based on the integrated antenna approach, and it is verified that the integrated antenna array can be implemented practically [29]. Last, the performance of the integrated antenna array compared to mono-polarization and dual-polarization dipole arrays is compared.The most recent antenna array technologies such as smart antenna system (SAS) and massive multiple-input multiple-output(MIMO) system are giving a strong and increasing impact relative to 5G wireless communication systems. This is due to the ben-efits that are obtainable in terms of performance improvements with respect to omnidi-rectional antennas. A considerable number of theoretical proposals have been presented in this field [30, 31]. However, the most commonly used network simulators do not implement the latest wireless network standards. Consequently, most simulators do not offer the possibility to emulate scenarios in which SAS and massive MIMO system are employed. This aspect heavily affects the quality of the network performance analysis with regard to the next generation wireless communication systems. To overcome this issue, it is possible, for example, to extend the default features offered by one of the most used network simulators such as Omnet++ which provides a very complete suite of network protocols and patterns that can be adapted in order to support the latest antenna array systems. The main goal of Chapter 6 is to illustrate the improvements accomplished in this field, allowing to enhance the basic functionalities of the Omnet++ simulator by implementing the most modern antenna array technologies [32].4Array Pattern OptimizationReferences[1] Balanis CA. Antenna Theory, Analysis and Design. 4th ed. Hoboken, New Jersey: Wiley; 2016[2] Mailloux RJ. Phased Array Antenna Handbook. 2nd ed. Norwood, MA: Artech House; 2005[3] Haupt RL. Antenna Arrays: A Computational Approach. Hoboken, New Jersey: John Wiley & Sons; 2010[4] Mohammed JR. An investigation into side lobe reduction and cancellation techniques [M.Sc. thesis]. College of Engineering, Mosul University; 2001[5] Sayidmarie KH, Mohammed JR. A simple technique for side lobe reduction and cancellation. Al-Rafiddin Engineering Journal. 2002;10(1):53-62[6] Sayidmarie KH, Mohammed JR. Design of a linear array with asymmetric low side lobes. Al-Rafiddin Engineering Journal. 2004;12(1):1-9[7] Sayidmarie KH, Mohammed JR.  A simple technique for sidelobe reduction and cancellation. Al Rafiddin Engineering Journal. 2002;10(1):53-62[8] Aboud AH, Sayidmarie KH. Reduction of sidelobe structure in phased arrays by auxiliary antenna. In: Asia-Pacific Radio Science Conference AP-RSC04; 24-27 August 2004; Qingdao, China. 2004[9] Aboud AH, Sayidmarie KH. Reduction of sidelobe structure in phased arrays by a 4-element auxiliary antenna. In: 3rd IEEE Int. Conf. On Systems, Signals & Devices; Tunisia. 2005[10] Mohammed JR, Sayidmarie KH. Sidelobe cancellation for uniformly excited planar array antennas by controlling the side elements. IEEE Antennas and Wireless Propagation Letters. 2014;13:987-990[11] Mohammed JR, Sayidmarie KH. A new technique for obtaining wide-angular nulling in the sum and difference patterns of monopulse antenna. IEEE Antennas and Wireless Propagation Letters. 2012;11:1245-1248. And its correction on 26 March 2013[12] Mohammed JR. Synthesizing sum and difference patterns with low complexity feeding network by sharing element excitations. International Journal of Antennas and Propagation. 2017;2017:7. Article ID 2563901[13] Mohammed JR. Synthesizing uniform sum and difference patterns by controlling steer angle and using sub-arrays. Global Journal of Research in Engineering. 2017;17(7):33-41[14] Sayidmarie KH, Mohammed JR. Performance of a wide angle and wideband nulling method for phased arrays. Progress in Electromagnetics Research. 2013;33:239-249[15] Mohammed JR, Sayidmarie KH. Null steering method by controlling two elements. IET Microwaves, Antennas and Propagation. 2014;8(15):1348-1355[16] Mohammed JR, Sayidmarie KH. Performance evaluation of the adaptive sidelobe canceller system with various auxiliary configurations. International Journal of Electronics and Communications. 2017;80:179-185[17] Mohammed JR, Sayidmarie KH. Synthesizing asymmetric side lobe pattern with steered nulling in nonuniformly excited linear arrays by controlling edge elements. International Journal of Antennas and Propagation. 2017;7:1-7[18] Mohammed JR. Element selection for optimized multi-wide nulls in 5Introductory Chapter: Introduction to Array Pattern OptimizationDOI: http://dx.doi.org/10.5772/intechopen.83596almost uniformly excited arrays. IEEE Antennas and Wireless Propagation Letters. 2018;17(4):629-632[19] Mohammed JR. Thinning a subset of selected elements for null steering using binary genetic algorithm. Progress in Electromagnetics Research. 2018;67:147-155[20] Mohammed JR. Optimal null steering method in uniformly excited equally spaced linear arrays by optimising two edge elements. Electronics Letters. 2017;53(13):835-837[21] Inserra D, Wen G. Communication area synthesis for next generation highway ETC systems. In: Proceeding of IEEE International Conference on Communications in China (ICCC’16); 27-29 July 2016; Chengdu, China. 2016. pp. 1-6[22] Inserra D, Wen G, Hu W. Linear optimization of antenna array for radiation pattern defined on a planar surface. Journal of Electromagnetic Waves and Applications. 2018;32(16):2030-2045[23] Inserra D, Hu W, Wen G. Antenna array synthesis for RFID-based electronic toll collection. IEEE Transactions on Antennas and Propagation. 2018;66(9):4596-4605[24] Inserra D, Hu W, Wen G. Design of a microstrip series power divider for sequentially rotated nonuniform antenna array. International Journal of Antennas and Propagation. 2017;8:1-8[25] Seeds AJ, Williams KJ. Microwave photonics. IEEE/OSA Journal of Lightwave Technology. 2006;24(12):4628-4641[26] Belkin ME, Golovin V, Tyschuk Y, Sigov AS. Comparison of RF photonics-based beamformers for super-wide bandwidth phased array antennas. IOP Conference Series: Materials Science and Engineering. 2017;198:1-4[27] Belkin ME, Golovin V, Tyschuk Y, Sigov AS. A simulation technique for designing next-generation information and communication systems based on off-the-shelf microwave electronics computer tool. International Journal of Simulation and Process Modelling. 2018;13(3):238-254[28] Glazunov AA. A survey of the application of the spherical vector wave mode expansion approach to antenna-channel interaction modeling. Radio Science. 2014;49(8):663-679[29] Park D, Cho DH. Analysis of pattern gain of compact directional 16-port antenna. IEEE Antennas and Wireless Propagation Letters. 2015;14:902-905[30] Lu L, Li G, et al. An overview of massive MIMO: Benefits and challenges. IEEE Journal of Selected Topics in Signal Processing. 2014;8(5):742-758[31] Molisch AF, Ratnam V, Han S, et al. Hybrid beamforming for massive MIMO: A survey. IEEE Communications Magazine. 2017;55(9):134-141[32] Inzillo V, De Rango F, Santamaria AF, Ariza AQ. A new switched beam smart antenna model for supporting asymmetrical communications extending Inet omnet++ framework. In: Proceedings of International Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS). 2017. pp. 1-7

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