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Antennas and Propagation Magazine, IEEE

Issue 6 • Date Dec. 2011

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Displaying Results 1 - 25 of 63
  • [Front cover]

    Publication Year: 2011 , Page(s): c1
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  • Table of contents

    Publication Year: 2011 , Page(s): 3
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  • Information for Contributors

    Publication Year: 2011 , Page(s): 4
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  • Magazine Staff

    Publication Year: 2011 , Page(s): 5 - 6
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  • AP-S Officers and Administrative Committee

    Publication Year: 2011 , Page(s): 7
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  • Feature Articles and Contributions Solicited

    Publication Year: 2011 , Page(s): 7
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  • Editor's Comments

    Publication Year: 2011 , Page(s): 8,259 - 262
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  • President's Message

    Publication Year: 2011 , Page(s): 8,263 - 263
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  • The receiving and scattering properties of a finite dipole array

    Publication Year: 2011 , Page(s): 9 - 17
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3716 KB) |  | HTML iconHTML  

    In this paper, a tutorial discussion is presented on the receiving and scattering properties of the finite dipole array. The primary issue that we consider here is the relationship between the total scattered and received powers for the free-space and the ground-plane-backed dipole arrays. We discuss how the conservation of power relates to the total scattered and received powers for the general antenna and the finite array. The definitions of aperture efficiency, absorption efficiency, and scattering area are reexamined, and their relationship to the concept of total power available to the receiving array is discussed. It is shown that the superposition of received and scattered powers is not a valid concept for determining the total power available to the equivalent load(s) connected to the receiving array. We show that when receiving the maximum possible power from the incident plane wave, both the free-space and ground-plane-backed arrays must scatter some power. View full abstract»

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  • Getting the Magazine by Air Freight

    Publication Year: 2011 , Page(s): 17
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  • AP-S Election Results

    Publication Year: 2011 , Page(s): 17
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  • Changes of Address or Delivery Problems

    Publication Year: 2011 , Page(s): 17
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  • Substrate-Integrated-Waveguide Beamforming Networks and Multibeam Antenna Arrays for Low-Cost Satellite and Mobile Systems

    Publication Year: 2011 , Page(s): 18 - 30
    Cited by:  Papers (24)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6376 KB) |  | HTML iconHTML  

    The growing complexity of satellite and mobile communication systems means that there are increasing needs for antenna arrays with multiple-beam capability. Conventional beamforming-network (BFN) configurations can be realized by different types of transmission lines, such as a microstrip line or waveguide. However, each of these has its own obvious defects. As part of a new generation of high-frequency integrated circuits, called substrate integrated circuits (SICs), substrate-integrated-waveguide (SIW) technology combines the benefits of both planar transmission-line and non-planar-waveguide technologies. It presents an excellent solution for the design and implementation of high-frequency beamforming networks, including for use at millimeter wavelengths. This paper overviews the state-of-the-art of substrate-integrated-waveguide techniques in the design and realization of innovative beamforming networks, and multibeam antenna arrays for low-cost satellite and mobile systems. Different classes of substrate-integrated-waveguide-based structures are theoretically and experimentally studied and demonstrated, to offer unprecedented performance and opportunities for specific space-and ground-based applications. View full abstract»

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  • Correction [to "Development of the Incremental IEMF Method to Validate FARS (Far-field Analysis of Radiation Sources)"]

    Publication Year: 2011 , Page(s): 30
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    There was an error in Equation (25) of the above-named work [ibid., vol 52, no 6, December 2010, pp. 46-54.] that is corrected here. View full abstract»

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  • Improved Performance of a Microstrip Phased Array Using Broadband and Ultra-Low-Loss Metamaterial Slabs

    Publication Year: 2011 , Page(s): 31 - 41
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4843 KB) |  | HTML iconHTML  

    A novel broadband and ultra-low-loss electric metamaterial EM isolation slab is proposed to improve the performance of a microstrip array. The metamaterial slab is formed by periodically grounded edge-coupled split-ring resonators (PGE-SRRs). Outstanding improvements - including over -50 dB peak isolation, 15% fractional bandwidth (-10 dB isolation) and almost lossless operation - are obtained. The metamaterial slab is inserted halfway between the adjacent E-coupled elements in the microstrip array to suppress mutual coupling. A strong mutual-coupling suppression of -16.8 dB was exhibited experimentally in a two-element microstrip array with an element spacing of three-quarters of the operating wavelength. Theoretical and numerical studies were done to improve the performance of microstrip phased arrays using the proposed metamaterial slab. The analysis indicated that the scan blindness in an infinite phased array is well eliminated, the wide-angle impedance matching is remarkably improved, and the scanning range is extended from [-13°, 13°] to [-28°, 28°]. A 7×3 microstrip array was simulated to study the influence of the metamaterial slab on the array's performance. The results indicated that the metamaterial slab can also enhance the radiation characteristics, extend the scanning range and suppressing grating lobes in microstrip phased arrays. View full abstract»

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  • Analysis and synthesis of millimeter-wave microstrip grid-array antennas

    Publication Year: 2011 , Page(s): 42 - 55
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5204 KB) |  | HTML iconHTML  

    This paper describes the analysis and synthesis of microstrip grid-array antennas at millimeter-wave frequencies. The basic principle of operation is revisited through careful examination of current distributions, impedance, and radiation characteristics on a typical microstrip grid-array antenna. An extensive analysis of microstrip grid-array antennas of different meshes on a variety of substrates is conducted, showing that the choice of substrate has a strong influence on the performance of the microstrip grid-array antenna. A set of closed-form formulas is obtained for an initial synthesis of a microstrip grid-array antenna. A particular design example is given. A comparison of simulated and measured performance showed good agreement, which confirmed the validity of the analysis and synthesis. View full abstract»

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  • Experiments with a Low-Profile Beamforming MIMO System for WLAN Applications

    Publication Year: 2011 , Page(s): 56 - 69
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6676 KB) |  | HTML iconHTML  

    MIMO technology has become one of the most promising techniques for enhancing the quality of services in many applications. For WLANs, the issue of MIMO technology has been officially addressed by the IEEE 802.11 n standard. In this standard, five MIMO operations - including spatial multiplexing, transmitting beamforming, space-time block coding, low-density parity-check encoding, and antenna selection - were described. Among these operations, the beamforming MIMO has the benefits of a low complexity with the highest improvement in signal-to-noise ratio. However, it is still requires high computational processing for estimating knowledge of the channel and for finding an appropriate steering vector. To reduce such computations, a selection of a fixed number of formed beams is proposed. In this paper, an experimental study of practically switched beamforming for WLAN applications is presented. Two types of antenna configurations, including 4×1 linear and 2×2 planar arrays, were considered. The results indicated the benefit of switched beamforming by improving average signal power strength by 10.25 dB. In addition, to reduce the burden of estimating the channel, the concept of selecting the best steering vector from the received signal strength instead of the channel information is proposed for low-profile beamforming MIMO systems. The prototype was completely constructed and practically tested. The results confirmed the successful improvement of the proposed prototype over using an omnidirectional antenna for WLAN applications. View full abstract»

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  • Development of Advanced Design Software for Complex Multimode Antenna Feeding Systems

    Publication Year: 2011 , Page(s): 70 - 82
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    Ka-band multiple-beam spacecraft antennas (MBA) are a key technological challenge in the design of broadband communication-satellite systems. Due to the very narrow beamwidth of multiple-beam spacecraft antennas, beam pointing is a critical issue, since even very small pointing errors can seriously affect the antenna's performance. Consequently, many of these communications antennas require closed-loop tracking. While full-wave design tools for multimode waveguide components have been well established since the mid-1990s, there was a perceived lack of similarly powerful design tools for multimode horn radiators. In order to close this technological gap, the European Space Agency (ESA) proposed a sponsored research effort, focusing on the development of multimode horn design software. The project was executed by a team consisting of MDA Satellite Systems, Canada, and Mician GmbH, Germany. While the software-requirements specification and its validation was the primary responsibility of MDA, Mician was responsible for the software implementation. This paper summarizes the work performed under this project, and also provides examples of complex multimode feed designs for multiple-beam spacecraft-antenna applications. View full abstract»

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  • The Father of Radio: A Brief Chronology of the Origin and Development of Wireless Communications

    Publication Year: 2011 , Page(s): 83 - 114
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    This paper presents a chronology of the origin and development of wireless (or radio) communications. It follows the following pattern. It gives credit to some of the scientists who provided the initial observations and understanding of electric and magnetic phenomena. It then mentions the experiments and inventions carried out toward the evolution of scientific and engineering models. Finally, it focuses on the implementation of practical wireless systems. The chronology leads us to conclude that the invention and development of wireless/radio systems can neither be credited to one individual nor to one specific country. The chronology strongly indicates an overlapping of human thinking in time in many countries. This compelled us to not make a definitive choice of an individual (or country) for the well-deserved credit. We leave it up to the reader to make her or his own choice! View full abstract»

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  • In Memoriam: Marek E. Bialkowski

    Publication Year: 2011 , Page(s): 115 - 117
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  • Announcement and call for papers

    Publication Year: 2011 , Page(s): 118
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  • Organized by Commission E of the International Union of Radio Science

    Publication Year: 2011 , Page(s): 119
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  • AP-S AdCom Minutes

    Publication Year: 2011 , Page(s): 120 - 127
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  • Announcement and call for papers

    Publication Year: 2011 , Page(s): 128
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  • The 10th Anniversary of the TELSIKS Conference

    Publication Year: 2011 , Page(s): 130 - 132
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Aims & Scope

The IEEE Antennas and Propagation Magazine covers all areas relating to antenna theory, design, and practice.

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Editor-in-Chief
Mahta Moghaddam