دانلود رایگان مقاله لاتین شبکه مارپیچ لگاریتمی از سایت الزویر
عنوان فارسی مقاله:
بازتابی شبکه مارپیچ لگاریتمی از آنتن های پایه اى در دهانه آن
عنوان انگلیسی مقاله:
Reflectarray with logarithmic spiral lattice of elementary antennas on its aperture
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
A flat or conformal reflecting surface made up of suitably 41 designed elementary antennas placed in a particular lattice, illumi- 42 nated by a feed antenna, constitutes a reflectarray. Electromagnetic 43 performances of the elementary antennas have to be suitably 44 designed in order to obtain the required performance of the whole 45 reflectarray system. Reflectarray is superior over a reflector in 46 terms of low-profile, light-weight, facile fabrication, easy installa- 47 tion and compatibility with active devices [1]. Also reflectarray 48 can be conformal to the mounting surface and require low space 49 where reflectors occupy a large space for its installation. Moreover, 50 reflectarray antennas offer the possibility of beam steering, like 51 conventional phased arrays, but eliminate the complexity and 52 losses of the feeding network, hence exhibiting higher efficiency 53 [1]. Thus, reflectarrays have several attractive applications includ- 54 ing earth stations, onboard antennas in satellite communication 55 systems, microspacecraft missions and antennas for radar, to name 56 just a few [2]. 57 A desired radiation pattern for a reflectarray can be achieved by 58 exploiting various parameters of the reflectarray. These parameters 59 include element shape, element spacing and location on the reflec- 60 tarray aperture, number of elements and aperture shape of the reflectarray. The effect of element shape [3,4], element spacing 61 [5] and aperture shape of the reflectarray [6,7] has been discussed 62 in literature for quite some time. Although substantial progress has 63 been achieved in the design of reflectarray with periodic configura- 64 tions of elementary antennas on its aperture but the impact of ape- 65 riodic configurations has not been studied much. Only recently 66 aperiodic array configurations have been studied [8] and some 67 attempts have been made to achieve optimized element locations 68 for aperiodic configurations on reflectarray aperture [9,10]. Impact 69 of aperiodic configuration of elementary antennas, in the form of 70 logarithmic spiral lattice, on reflectarray aperture for fixed beam 71 applications is the focus of this paper. 72 Conventionally, grid patterns of elementary antennas on reflec- 73 tarray aperture are in the form of periodic rectangular or circular 74 lattice. Although logarithmic or golden spiral lattice has been 75 reported in the literature for conventional microstrip arrays [11] 76 but it has never been reported in the context of reflectarray. In this 77 paper, a reflectarray with logarithmic spiral lattice of microstrip 78 patches of varying length has been designed, simulated and fabri- 79 cated; where measured results are in good agreement with the 80 simulated patterns. This type of lattice is used because it guaran- 81 tees a really good radial and azimuth spreading in the element 82 positions [12]. It also allows the reduction of side lobe level with- 83 out resorting to an amplitude tapering [11]. Moreover, no grating 84 lobes appear in a logarithmic spiral lattice especially when the 85 array is electronically scanned [12]. In addition, the logarithmic spiral lattice has almost equal unit cell size per radiating element 88 thus unit cell characterization can be done using infinite array 89 approach as in conventional rectangular lattice [18]. 90 In the last section of the paper, a performance comparison of 91 the reflectarray with logarithmic spiral lattice has been carried 92 out with reflectarrays having conventional rectangular and circular 93 lattices. Reflectarray with logarithmic spiral lattice shows signifi- 94 cant improvements in side lobe levels as compared to reflectarrays 95 with conventional lattices.
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کلمات کلیدی:
Research paper (PDF): Reflectarray with Logarithmic Spiral Lattice of ... https://www.researchgate.net/.../302554864_Reflectarray_with_Logarithmic_Spiral_Latt... A reflectarray with logarithmic spiral lattice of elementary antennas on its aperture is presented. In a logarithmic spiral lattice, elementary antennas are arranged ... Aperture efficiency analysis of reflectarray antennas - Yu - 2009 ... onlinelibrary.wiley.com/doi/10.1002/mop.24949/abstract by A Yu - 2010 - Cited by 39 - Related articles Dec 8, 2009 - In the design procedure of a reflectarray antenna system, the aperture efficiency needs to be first analyzed to forecast the system performance. A simple approach to achieve polarization diversity in broadband ... onlinelibrary.wiley.com/doi/10.1002/mop.28833/abstract by L Guo - 2015 - Cited by 6 - Related articles Dec 18, 2014 - ABSTRACT. This article presents a simple method to realize polarization diversity in broadband reflectarrays. The wideband characteristic of ... Research / Reflector and Reflect Array Antennas | MERL, NUST ... merleme.org/research-antennas-reflect.php Wasif Niaz, Zubair Ahmed, Mojeeb Bin Ihsan, "Reflectarray with Logarithmic Spiral Lattice of Elementary Antennas on its Aperture", AEU-International Journal of ... Research / Publications | MERL, NUST College of E&ME, Rawalpindi ... merleme.org/research-publications.php Wasif Niaz, Zubair Ahmed, Mojeeb Bin Ihsan, "Reflectarray with Logarithmic Spiral Lattice of Elementary Antennas on its Aperture", AEU-International Journal of ... Sparrho | A certain feature of logarithmic spirals www.sparrho.com/item/a-certain-feature-of-logarithmic-spirals/ae8022/ A curve formed by inversion of a logarithmic spiral is called a double ... Reflectarray with Logarithmic Spiral Lattice of Elementary Antennas on its Aperture. [PDF]Phyllotaxis or the properties of spiral lattices. - II. Packing of circles ... https://hal.inria.fr/docs/00/21/10/20/PDF/ajp-jphys_1989_50_13_1603_0.pdf by F Rothen - Cited by 28 - Related articles Jan 1, 1989 - 2014 Phyllotaxis can be identified with the study of spiral lattices which are ... circles aligned along a logarithmic spiral. using conditions for ... Sunflower Array Antenna with Adjustable Density Taper - Hindawi https://www.hindawi.com/journals/ijap/2009/624035/citations/ Jan 5, 2009 - ... “Phase-Only Synthesis Of Flat Aperiodic Reflectarrays,” Progress in ... and Mojeeb Bin Ihsan, “Reflectarray with logarithmic spiral lattice of ...
