Advances in Satellite Communications Part 1 pptx

Contents Preface IX Part 1 Antennas in Satellite Communications 1 Chapter 1 Helical Antennas in Satellite Radio Channel 3 Maja Škiljo and Zoran Blažević Part 2 Atmospheric Effects in

ADVANCES IN

SATELLITE COMMUNICATIONS

Edited by Masoumeh Karimi

and Yuri Labrador

Advances in Satellite Communications

Edited by Masoumeh Karimi and Yuri Labrador

Published by InTech

Janeza Trdine 9, 51000 Rijeka, Croatia

Copyright © 2011 InTech

All chapters are Open Access articles distributed under the Creative Commons

Non Commercial Share Alike Attribution 3.0 license, which permits to copy,

distribute, transmit, and adapt the work in any medium, so long as the original

work is properly cited After this work has been published by InTech, authors

have the right to republish it, in whole or part, in any publication of which they

are the author, and to make other personal use of the work Any republication,

referencing or personal use of the work must explicitly identify the original source Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published articles The publisher assumes no responsibility for any damage or injury to persons or property arising out

of the use of any materials, instructions, methods or ideas contained in the book

Publishing Process Manager Mia Devic

Technical Editor Teodora Smiljanic

Cover Designer Jan Hyrat

Image Copyright Chaikovskiy Igor, 2010 Used under license from Shutterstock.com

First published July, 2011

Printed in Croatia

A free online edition of this book is available at www.intechopen.com

Additional hard copies can be obtained from orders@intechweb.org

Advances in Satellite Communications, Edited by Masoumeh Karimi and Yuri Labrador

p cm

ISBN 978-953-307-562-4

free online editions of InTech

Books and Journals can be found at

www.intechopen.com

Contents

Preface IX

Part 1 Antennas in Satellite Communications 1

Chapter 1 Helical Antennas in Satellite Radio Channel 3

Maja Škiljo and Zoran Blažević

Part 2 Atmospheric Effects in Satellite Links over Ka Band 27

Chapter 2 Theoretical Analysis of Effects of

Atmospheric Turbulence on Bit Error Rate for Satellite Communications in Ka-band 29

Tatsuyuki Hanada, Kiyotaka Fujisaki and Mitsuo Tateiba

Part 3 Real Time Applications over Satellite 53

Chapter 3 Improving Quality-of-Service of Real-Time

Applications over Bandwidth Limited Satellite Communication Networks via Compression 55

LingSun Tan, SeiPing Lau and ChongEng Tan

Part 4 Hybrid Satellite-Terrestrial Networks 81

Chapter 4 Multicast Security and Reliable Transport

of Rekey Messages over Hybrid Satellite/Terrestrial Networks 83

Franco Tommasi, Elena Scialpi and Antonio De Rubertis

Part 5 Sensor Networks 109

Chapter 5 Design Issues of an Operational Fire Detection

System integrated with Observation Sensors 111

George Halikias, George Leventakis, Charalambos Kontoes, Vasilis Tsoulkas,

Leonidas Dritsas and Athanasios Pantelous

VI Contents

Part 6 High Capacity Satellite Communications 133

Chapter 6 Passive Microwave Feed Chains for High

Capacity Satellite Communications Systems 135

Giuseppe Addamo, Oscar Antonio Peverini,

Giuseppe Virone and Riccardo Tascone

Part 7 Adaptive Antenna Arrays 165

Chapter 7 New Antenna Array Architectures

for Satellite Communications 167

Miguel A Salas Natera, Andrés García-Aguilar, Jonathan Mora-Cuevas, José-Manuel Fernández González, Pablo Padilla de la Torre, Javier García-Gasco Trujillo, Ramón Martínez Rodríguez-Osorio, Manuel Sierra Pérez, Leandro de Haro Ariet and Manuel Sierra Castañer

Preface

The use of satellites in communications systems is very much a fact of everyday life, as

is evidenced by the many homes equipped with antennas, or dishes used for reception

of satellite television What may not be so well known is that satellites form an essential part of telecommunication systems worldwide, carrying large amounts of data and telephone traffic in addition to the television signals

Satellite communication systems are now a major part of most telecommunications networks as well as our everyday lives through mobile personal communication systems and broadcast television A sound understanding of such systems is therefore important for a wide range of system designers, engineers and users

Satellites offer a number of features not readily available with other means of communications Because very large areas of the earth are visible from a satellite, the satellite can form the star point of communications network, simultaneously linking many who may be widely separated geographically The same features enable satellites to provide communication links to remote communities in sparsely populated areas that are difficult to access by other means Of course, satellites' signals ignore political boundaries as well as geographic ones, which may or may not be a desirable feature

A satellite communications system uses a variety of technologies combining many areas of engineering fields, from video compression to access techniques, modulation schemes, and error correction capabilities In addition, a satellite link engineer has to consider the constrains of the communication channel; so many radio frequency calculations are needed, these include link budget analysis, propagation effects, amplifiers' operational points, antennas size, transmission lines, impedance matching, etc

This book provides a comprehensive review of some applications that have driven this growth It analyzes various aspects of Satellite Communications from Antenna design, Real Time applications, Quality of Service (QoS), Atmospheric effects, Hybrid Satellite-Terrestrial Networks, Sensor Networks and High Capacity Satellite Links

It is the desire of the editors that the topics selected for this book can give the reader an overview of the current trends in Satellite Systems, and also an in depth analysis of the

X Preface

technical aspects of each one of them The editors would like to acknowledge the support of all of those people at the InTech (Open Access Publisher) who have helped during the process of this book In particular, special thanks to Ms Mia Devic for her valuable comments, hard work and continued guidance

Dr Masoumeh Karimi

Technological University of America,

USA

Dr Yuri Labrador

The MITRE Corporation,

USA

Part 1 Antennas in Satellite Communications

1 Helical Antennas in Satellite Radio Channel

Maja Škiljo and Zoran Blažević

University of Split, Faculty of electrical engineering, mechanical engineering and naval architecture,

Croatia

1 Introduction

Monofilar and multifilar helical antennas are the most widely proposed antennas in satellite communications systems The main reason why these antennas constitute an asset in applications concerning satellite and space communications generally is circular polarization Good axial ratio provides precise measurement of the polarization of the received signal due to immunity of the circularly polarized wave to Faraday rotation of the signal propagating through the ionosphere

In addition to circular polarization, monofilar helical antennas offer the advantage of high gain in axial direction over a wide range of frequencies which makes them suitable for applications in broadband satellite communications Split beam and conical beam radiation patterns of bifilar and quadrifilar helical antennas respectively, offer even more applications

in mobile satellite communications (Kilgus, 1975; Nakano et al., 1991) Also, backfire helical antenna has stood out as a better feed element for parabolic reflector than the axial mode helical antenna and horn antennas (Nakano et al., 1988) Beside the number of wires in helical antenna structure, it is possible to use antenna’s physical parameters to control the directivity pattern Phase velocity of the current can be controlled by changing the pitch angle and circumference (Kraus, 1988; Mimaki & Nakano, 1998), and the ground plane can

be varied in its size and shape to achieve a certain form of radiation pattern and higher antenna gain (Djordjevic et al., 2006; Nakano et al., 1988; Olcan et al., 2006) Various materials used in helical antenna design, even only for the purpose of mechanical support or isolation, can noticeably influence the antenna’s performance so this should be taken into account when designing and modeling the desirable helical antenna structure (Casey & Basal, 1988a; Casey & Basal, 1988b; Hui et al., 1997; Neureuther et al., 1967; Shestopalov et al., 1961; Vaughan & Andersen, 1985)

A theoretical study of a sheath, tape and wire helix given in (Sensiper, 1951) provided the base for a physical model of the helical antenna radiation mechanism The complex solutions of the determinantal equation for the propagation constants of the surface waves traversing a finite tape helix are used to calculate the current distribution on helical antenna

in (Klock, 1963) The understanding of the waves propagating on the helical antenna structure can also provide a good assessment of the circular polarization purity as well as the estimation of varying the helical antenna radiation characteristics by changing the antenna’s physical parameters and using various materials in helical antenna design (Maclean & Kouyoumjian, 1959; Neureuther et al., 1967; Vaughan & Andersen, 1985)