Advances in Satellite Communications

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... dielectric coating non-loss EDT lossy EDT 2.2 2 1.8 1.6 1.8 1.9 2 2.1 2.2 2.3 2.4 Frequency (GHz) b) Fig 7 The simulation results of material influence on antenna a) gain and b) VSWR 14 Advances in Satellite Communications Various shapes of ground plane were considered: infinite ground plane, square conductor, cylindrical cup and truncated cone, whereas the later produced the highest gain increase relative... varied in order to obtain a wider bandwidth with higher antenna gain In (Skiljo et al., 2010) the axial mode bandwidth was examined by means of parameters defining the limits of the axial radiation mode: axial ratio, HPBW, side lobe level (SLL) and total gain in axial direction, whereas the method of changing the pitch angle was applied to a helical antenna wounded around a hollow dielectric cylinder... toroidal pattern providing higher diversity gain in all directions (Amin et al., 2007) In order for the bifilar helix to operate as backfire antenna, it is necessary that the currents flowing from the terminals to the ends of two helices are out of phase and the currents in the reversed direction are in phase Hence, no radiation in forward direction is possible This could be explained by the nature of... phase lag of 45° Instead of infinite balun, we proposed a stripline structure for impedance matching and the support for helical wire Fig 15 c) shows that matching stripline is made of shorter part designed to counteract the imaginary part of the antenna input impedance and longer quarterwave part which is used to tune the real component of antenna input impedance to 50-Ω coaxial line impedance (Sekelja... matching solutions The chapter is concluded with the comparison of these antennas and their application in satellite communications 2 Monofilar helical antennas The helical antenna was invented by Kraus in 1946 whose work provided semi-empirical design formulas for input impedance, bandwidth, main beam shape, gain and axial ratio based on a large number of measurements and the antenna array theory In. .. m (1) (2) 6 Advances in Satellite Communications The element factors Fθm and Fϑm represent the contribution of each turn to the total field in some far point of the space due to the mth cylindrical space harmonic, and are determined as: m a  a Fθ m (θ ,ϑ ) = 2  Ezm cot ϑ − Eθam sin ϑ  J m − jZ0 H zm ( J m + 1 − J m − 1 ) ,  ka  (3) m a  a Fϑ m (θ ,ϑ ) = 2Z0  H zm cot ϑ − Hθam sin ϑ  J m +... results in Fig 9 depict that HPBW is mainly better in case of the truncated cone reflector but worse with the round reflector, and the antenna gain is improved when using the truncated cone Also, Fig 9 b) shows a significant gain increase of the double pitch helical antenna with truncated cone reflector in comparison with the standard one around 2.4 GHz, but the bandwidth of such an antenna gain is not increased... above the cut-off frequency of the main mode of the 18 Advances in Satellite Communications helical waveguide The beamwidth broadens with frequency and for pitch angles of about forty five degrees, the beam splits and turns into a scanning mode toward broadside direction As opposed to monofilar helical antenna, the backfire BHA radiates toward the feed point, its gain is independent of length (provided... traversing the arbitrary sized helical antenna may still be sought using a variational technique, assuming the existence of only two principal propagation modes (normal and axial), and a sinusoidal current distributions for each of them taking into account the velocities calculated for the infinite helical waveguide, as shown by (Klock, 1963) However, as the formula for the total current on the helix involves . 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, . 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. ADVANCES IN SATELLITE COMMUNICATIONS Edited by Masoumeh Karimi and Yuri Labrador Advances in Satellite Communications Edited by Masoumeh