2009 Index IEEE Antennas and Wireless Propagation Letters Vol. 8

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

2008 Index IEEE Transactions on Control Systems Technology Vol. 16

This index covers all technical items - papers, correspondence, reviews, etc. - that appeared in this periodical during the year, and items from previous years that were commented upon or corrected in this year. Departments and other items may also be covered if they have been judged to have archival value. The Author Index contains the primary entry for each item, listed under the first author\u27s name. The primary entry includes the coauthors\u27 names, the title of the paper or other item, and its location, specified by the publication abbreviation, year, month, and inclusive pagination. The Subject Index contains entries describing the item under all appropriate subject headings, plus the first author\u27s name, the publication abbreviation, month, and year, and inclusive pages. Note that the item title is found only under the primary entry in the Author Index

Comparative study of increasing indoor WLAN coverage by passive repeating systems

Abstract. Propagation of radio waves is interrupted while traveling through different materials. The architectural beautification and complexity by using various building materials cause attenuation of the signal via indoor, outdoor to indoor and vice versa wireless communications. It has been found that feeding more power to the transmitter or increasing sensitivity of the receiver is one of the solutions to overcome weak connectivity. However, this approach is not cost effective. Another concern is the ability to amplify the wireless signal, especially in WLAN operation. WLAN is one of the most popular ways of establishing a wireless communication network to connect our daily used devices such as mobile phone, laptop, IP camera etc. Path loss, attenuation by materials and the delivered power from the transceiver are the variables to determine the efficiency of this communication network. A passive repeating method has been discussed in this thesis which addresses the mentioned concerns. It is cost effective and in a case of power consumption, does not need any energy outside the system. On the other hand, there are few maintenance costs, if any, for this kind of system. To achieve this, a back-to-back antenna approach has been tested in this study. In a back-to-back system, two antennas are connected by a short waveguide connection to decrease attenuation e.g. a wall. The main challenge concerning the effectiveness of this method was to design and fabricate efficient antennas, which are connected with a coaxial cable. There are multiple frequency bands available for WLAN communication. In this thesis, a frequency of 2.43 GHz is considered. Computer simulation of antennas, fabrication, individual measurement and full passive repeating system measurement has been presented. A prototype of a circular patch antenna is built with a 4.63 dB gain and a return loss of 15.18 dB. The passive repeating system is built by using a commercially available dipole antenna at the other end of the coaxial cable. In various cases, there was an observable improvement of the signal of between 2 dB to 6 dB. Required background and theoretical studies are presented along with the output of the simulated and measured prototype comparison. It is clear from this study that the passive repeating system can be used in some specific indoor areas. Keywords: WLAN, passive repeater, path loss, attenuation, indoor communication

Design of dielectric resonator antenna arrays for wireless applications

This thesis presents design of dielectric resonator antenna array for wireless applications. Three antenna designed are presented in the following sections. The first design is a notched chamfered two element rectangular dielectric resonator antenna (DRA) array for wireless (WLAN and WIMAX) applications. Here the DRA array is excited by conformal patch connected to microstrip line. The shape is notched and chamfered to improve the performance of the antenna. From the Simulation results it can be observed that the proposed antenna covers 2.4, 3.6 and 5 GHz WLAN bands and 3.4 to 3.7 GHz WIMAX bands, achieving an impedance bandwidth from 2.18 to 3.75 GHz and 4.84 to 5.14 GHz. Parametric study is done by varying the shapes of the rectangular DRA arrays (Simple Rectangle, chamfered and chamfered with notched). Another parametric study is carried out by varying the dimension of the ground plane of the final design. The second design is a rectangular shaped two element Dielectric Resonator Antenna (DRA) array for 2.4 GHz WLAN application. Here microstrip feed line in corporate (parallel) arrangement is used for feeding. Simulation result shows that the antenna achieves a bandwidth from 2.1 to 3 GHz, covering the 2.4 GHz WLAN band. Here the parametric study is done by varying the feed line and the ground plane of the antenna. The simulation results as well as the parametric studies are incorporated in this thesis. The third one is the Design of four element rectangular shaped dielectric resonator antenna (RDRA) array for wireless applications. The RDRA array is fed by rectangular conformal patch (RCP) connected to microstrip line. Simulation result shows that the proposed antenna achieves an impedance bandwidth from 4 GHz to 7.1 GHz covering various wireless bands. Parametric studies have been carried out by varying the RCP height and the ground plane of the final design

Design synthesis and miniaturization of multiband and reconfigurable microstrip antenna for future wireless applications

Tese de Doutoramento. Engenharia Electrónica e de Computadores - Telecomunicações. Faculdade de Engenharia. Universidade do Porto. 201

Antennas and Propagation Aspects for Emerging Wireless Communication Technologies

The increasing demand for high data rate applications and the delivery of zero-latency multimedia content drives technological evolutions towards the design and implementation of next-generation broadband wireless networks. In this context, various novel technologies have been introduced, such as millimeter wave (mmWave) transmission, massive multiple input multiple output (MIMO) systems, and non-orthogonal multiple access (NOMA) schemes in order to support the vision of fifth generation (5G) wireless cellular networks. The introduction of these technologies, however, is inextricably connected with a holistic redesign of the current transceiver structures, as well as the network architecture reconfiguration. To this end, ultra-dense network deployment along with distributed massive MIMO technologies and intermediate relay nodes have been proposed, among others, in order to ensure an improved quality of services to all mobile users. In the same framework, the design and evaluation of novel antenna configurations able to support wideband applications is of utmost importance for 5G context support. Furthermore, in order to design reliable 5G systems, the channel characterization in these frequencies and in the complex propagation environments cannot be ignored because it plays a significant role. In this Special Issue, fourteen papers are published, covering various aspects of novel antenna designs for broadband applications, propagation models at mmWave bands, the deployment of NOMA techniques, radio network planning for 5G networks, and multi-beam antenna technologies for 5G wireless communications

Design and Analysis of a Cylindrical Dielectric Resonator Antenna Array and Its Feed Network

There is an ever increasing need for smaller, lighter, more efficient antennas for commercial and military applications. One such antenna that meets these requirements is the dielectric resonator antenna (DRA). In recent years there has been an abundance of research on the utilization of the DRA as a radiating element. However, its practical application - especially pertaining to DRA arrays - is still considered to be at its infancy. The purpose of this work is to present a systematic process to be used in the design, simulation, optimization, fabrication, and testing of a cylindrical DRA array including its associated feed network. The DRA array development cycle begins with a single cylindrical radiating element. ComDRA parameters such as DRA radius, feed type, feed location, and element spacing are investigated. A DRA element in this research is optimized for bandwidth and gain for use at x-band (8-12 GHz). The antenna feed network, being an integral part of all antenna arrays, is also considered. The primary causes of impedance mismatch in the feed network are identified and techniques to improve performance are explored. An improvement in impedance bandwidth is gained through traditional transmission line matching methods. Ultimately, a 16 (4x4) element and 256 (16x16) element array is fabricated, tested, and compared to an existing commercial technology

Metamaterials in Application to Improve Antenna Parameters

In recent years, the demand for miniaturization and integration of many functions of telecommunication equipment is of great interest, especially devices that are widely used in life such as mobile communication systems, smart phones, handheld tablets, GPS receivers, wireless Internet devices, etc. To satisfy this requirement, the mobile device components must be compact and capable of multifunction, multifrequency band operation. An antenna is one of them; it means that it must be conformal to the body of device, reduced in size, and capable to operating at multiple frequencies of mobile communication systems that have been operating on one, so-called smart device. Nowadays, there are many technical solutions applied in the antenna construction to satisfy of those requirements. There are microstrip antenna technology miniaturized by means of high-permittivity dielectric substrate, using shorting wall, shorting pins, some deformation, as the fractal geometry is, and others. However, these methods have disadvantage such as narrow bandwidth and low gain. A new solution that is of great interest to designers is the use of electromagnetic metamaterials for antenna design. The use of metamaterials in antenna design not only dramatically reduces the size of the antenna but can also improve other antenna parameters such as enhancing bandwidth, increasing gain, or generating multiband frequencies of antennas operation

Design of a 2.4 GHz Horizontally Polarized Microstrip Patch Antenna using Rectangular and Circular Directors and Reflectors

In the urban or indoor wireless environment, after a complicated multiple reflection or scattering effect, the polarization of the propagating radio waves may change significantly. Although many current wireless systems are vertically polarized it has been predicted that using horizontally polarized antenna at both the transmitter and receiver has many advantages. In this thesis, new designs are proposed to develop a horizontally polarized microstrip patch antennas for 2.4 GHz applications using directors and reflectors to guide the radiated power. The radiation characteristics of these designs with respect to various geometrical parameters such as the dimensions of the reflector and directors, and spacing between these elements were studied in order to obtain the best possible performance. Also, two-dimensional and three-dimensional radiation patterns, antenna gain and return loss for each of these designs are presented