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Author

J.R. James

Bio: J.R. James is an academic researcher from Loughborough University. The author has contributed to research in topics: Antenna efficiency & Antenna (radio). The author has an hindex of 6, co-authored 13 publications receiving 2627 citations.

Papers
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Book
01 Jan 1989
TL;DR: Analysis and design of circular microstrip elements micro Strip patch antennas circular polarization and bandwidth electromagnetically coupled dipoles multilayer configurations large bandwidth hybrid flat dipoles and arrays numerical analysis of microstrip patch antennas segmentation and desegmentation methods for microstrip antenna design transmission line model.
Abstract: Analysis and design of circular microstrip elements microstrip patch antennas circular polarization and bandwidth electromagnetically coupled dipoles multilayer configurations large bandwidth hybrid flat dipoles and arrays numerical analysis of microstrip patch antennas segmentation and desegmentation methods for microstrip antenna design transmission line model of microstrip antennas design and technology of low cost printed antennas analysis and design considerations of printed array antennas circularly polarized array antennas microstrip antenna feeds advances in substrate technology special measurement techniques for printed antennas CAD of microstrip and triplate systems resonant microstrip antenna elements and arrays applications of microstrip antennas monolithic conical conformal microstrip tracking antenna extensions and variations of the microstrip antenna concept.

1,501 citations

Book
01 Jan 1981
TL;DR: This book discusses techniques and design limitations in two-dimensional arrays of flat-plate antennas, some manufacturing and operational problems of microstrip antennas, and other trends and possible future developments.
Abstract: * Chapter 1: Flat-plate antenna techniques and constraints on performance * Chapter 2: Microstrip design equations and data * Chapter 3: Radiation mechanism of an open-circuit microstrip termination - fundamental design implications * Chapter 4: Basic methods of calculation and design of patch antennas * Chapter 5: Linear array techniques * Chapter 6: Techniques and design limitations in two-dimensional arrays * Chapter 7: Circular polarisation techniques * Chapter 8: Some manufacturing and operational problems of microstrip antennas * Chapter 9: Recent advances in microstrip antenna analysis * Chapter 10: Other trends and possible future developments

598 citations

Book
01 Feb 2001
TL;DR: In this paper, the relationship between all the elements involved in the design of antennas for mobile communications is discussed from a systems-oriented approach, providing a detailed discussion of equipment mountings, proximity of obstacles, and propagation phenomena.
Abstract: From the Publisher: Understand the relationship between all the elements involved in the design of antennas for mobile communications with this book Written from a systems-oriented approach, it provides a detailed discussion of equipment mountings, proximity of obstacles, and propagation phenomena It also presents the innovations that the printed antenna has made possible — such as compact adaptive arrays to combat fading Supplemented with 184 equations and 461 illustrations

488 citations

Journal ArticleDOI
TL;DR: In this article, the benefits resulting from the inclusion of ferrite in material loaded antennas are investigated, initially through the use of a spherical analytic model and then through a transmission line matrix simulation tool applied to a rectangular slab geometry.
Abstract: The benefits resulting from the inclusion of ferrite in material loaded antennas are investigated, initially through the use of a spherical analytic model and then through a transmission line matrix simulation tool applied to a rectangular slab geometry. It is observed that a material with equality of relative permittivity and permeability in combination with specific positioning of the antenna in relation to the head, can result in the definitive small-size, high efficiency and bandwidth, low specific absorption rate (SAR) antenna. The accuracy of the simulations is validated both through efficiency and SAR measurements of three material coated monopole samples. Further research into optimizing the above attributes and translating them into a handset antenna leads to a multiband antenna design covering the GSM 1800, 1900, UMTS and Bluetooth bands, with a SAR value reduced by 88% compared to conventional phones and an efficiency of 38% at 1.8 GHz. A tri-band antenna design is also presented, utilizing currently available lossy ferrite material and it is considered as the first step towards the feasibility of the ultimate low SAR multiband ferrite handset antenna, until further material development specifically for antenna applications takes place

76 citations

04 Apr 1989
TL;DR: In this paper, the authors highlighted innovative designs, novelty and creative ideas reported in the international antenna literature, highlighted under the headings of elements, travelling-wave arrays, apertures, arrays, measurements, and material developments.
Abstract: Innovative designs, novelty and creative ideas reported in the international antenna literature, are highlighted under the headings of elements, travelling-wave arrays, apertures, arrays, measurements, and material developments. Manufacturing and operational aspects are noted and the driving forces identified while the extent to which antenna technology is mature, the role of research, and degrees of design freedom are central themes that are considered in some depth. Factors of influence and innovation likely to be experienced by 1994 are conjectured together with some speculation for the more distant future. The author concludes that antenna technology will remain a vibrant topic, rich in creative ideas as long as the system demands persist.

13 citations


Cited by
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Book
31 Jul 1997
TL;DR: This book explores the meta-heuristics approach called tabu search, which is dramatically changing the authors' ability to solve a host of problems that stretch over the realms of resource planning, telecommunications, VLSI design, financial analysis, scheduling, spaceplanning, energy distribution, molecular engineering, logistics, pattern classification, flexible manufacturing, waste management,mineral exploration, biomedical analysis, environmental conservation and scores of other problems.
Abstract: From the Publisher: This book explores the meta-heuristics approach called tabu search, which is dramatically changing our ability to solve a hostof problems that stretch over the realms of resource planning,telecommunications, VLSI design, financial analysis, scheduling, spaceplanning, energy distribution, molecular engineering, logistics,pattern classification, flexible manufacturing, waste management,mineral exploration, biomedical analysis, environmental conservationand scores of other problems. The major ideas of tabu search arepresented with examples that show their relevance to multipleapplications. Numerous illustrations and diagrams are used to clarifyprinciples that deserve emphasis, and that have not always been wellunderstood or applied. The book's goal is to provide ''hands-on' knowledge and insight alike, rather than to focus exclusively eitheron computational recipes or on abstract themes. This book is designedto be useful and accessible to researchers and practitioners inmanagement science, industrial engineering, economics, and computerscience. It can appropriately be used as a textbook in a masterscourse or in a doctoral seminar. Because of its emphasis on presentingideas through illustrations and diagrams, and on identifyingassociated practical applications, it can also be used as asupplementary text in upper division undergraduate courses. Finally, there are many more applications of tabu search than canpossibly be covered in a single book, and new ones are emerging everyday. The book's goal is to provide a grounding in the essential ideasof tabu search that will allow readers to create successfulapplications of their own. Along with the essentialideas,understanding of advanced issues is provided, enabling researchers togo beyond today's developments and create the methods of tomorrow.

6,373 citations

Book
30 Nov 1993
TL;DR: Details of Element Pattern and Mutual Impedance Effects for Phased Arrays and Special Array Feeds for Limited Field of View and Wideband Arrays are presented.
Abstract: Phased Arrays in Radar and Communication Systems. Pattern Characteristics and Synthesis of Linear and Planar Arrays. Patterns of Nonplanar Arrays. Elements, Transmission Lines, and Feed Architectures for Phased Arrays. Summary of Element Pattern and Mutual Impedance Effects. Array Error Effects. Special Array Feeds for Limited Field of View and Wideband Arrays.

2,233 citations

01 Jan 1992
TL;DR: In this article, a brief overview of the basic characteristics of microstrip antennas is given, and the most significant developments in microstrip antenna technology have been made in the last several years.
Abstract: Microstrip antennas have been one of the most innovative topics in antenna theory and design in recent years, and are increasingly finding application in a wide range of modern microwave systems. This paper begins with a brief overview of the basic characteristics of microstrip antennas, and then concentrates on the most significant developments in microstrip antenna technology that have been made in the last several years. Emphasis is on new antenna configurations for improved electrical performance and manufacturability and on advances in the analytical modeling of microstrip antennas and arrays. >

1,604 citations

Journal ArticleDOI
23 Mar 2012
TL;DR: This paper gives a basic review and a summary of recent developments for leaky-wave antennas (LWAs), a guiding structure that supports wave propagation along the length of the structure, with the wave radiating or “leaking” continuously along the structure.
Abstract: This paper gives a basic review and a summary of recent developments for leaky-wave antennas (LWAs). An LWA uses a guiding structure that supports wave propagation along the length of the structure, with the wave radiating or “leaking” continuously along the structure. Such antennas may be uniform, quasi-uniform, or periodic. After reviewing the basic physics and operating principles, a summary of some recent advances for these types of structures is given. Recent advances include structures that can scan to endfire, structures that can scan through broadside, structures that are conformal to surfaces, and structures that incorporate power recycling or include active elements. Some of these novel structures are inspired by recent advances in the metamaterials area.

988 citations

Journal ArticleDOI
01 Dec 2001
TL;DR: In this paper, a high gain planar antenna with an optimized partially reflecting surface (PRS) placed in front of a waveguide aperture in a ground plane was investigated, where the antenna performance was initially related to the reflection characteristics of the PRS array following an approximate analysis.
Abstract: A high gain planar antenna has been investigated, using an optimised partially reflecting surface (PRS) placed in front of a waveguide aperture in a ground plane. The antenna performance is initially related to the reflection characteristics of the PRS array following an approximate analysis. The array geometry is optimised using an analytical formula. The optimisation results are verified using a full wave model taking into account the edge effects. The array size for maximum antenna efficiency has also been investigated.

611 citations