December 2012 - URSI

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Contents Editorial ....................................................................................................................... 3 In Memoriam ............................................................................................................... 4 Physics of Propagation in a Cellular Wireless Communication Environment ...... 5 RadioAstron: An Earth-Space Radio Interferometer with a 350,000 km Baseline .................................................................................................................. 22 The International Council for SciencePledges Support for Scientists in the L’Aquila Case ........................................................................................................ 29 Book Reviews for Radioscientists ............................................................................ 30 Conferences ............................................................................................................... 34 International Geophysical Calendar 2013 .............................................................. 41 ICEAA - IEEE APWC - EMS .................................................................................. 47 Electromagnetic Metrology Symposium ................................................................. 48 AP-RASC’13 .............................................................................................................. 49 URSI F Triennial Open Symposium ........................................................................ 50 Journées Scientifiques ............................................................................................... 51 List of URSI Officials ................................................................................................ 52 Information for authors ........................................................................................... 77 Front cover: The 10 m RadioAstron Space Radio Telescope with the petals unfurled. See the paper by N.S. Kardashev, Y.Y. Kovalev, and I. Kellerman on pp. 22 - 29. EDITOR-IN-CHIEF EDITORIAL ADVISORY BOARD EDITOR URSI Secretary General Phil Wilkinson W. Ross Stone Paul Lagasse (URSI President) 840 Armada Terrace Dept. of Information Technology W. Ross Stone San Diego, CA92106 Ghent University PRODUCTION EDITORS USA St. Pietersnieuwstraat 41 Inge Heleu Tel: +1 (619) 222-1915 B-9000 Gent Inge Lievens Fax: +1 (619) 222-1606 Belgium E-mail: r.stone@ieee.org SENIOR ASSOCIATE EDITORS Tel.: (32) 9-264 33 20 O. Santolik Fax : (32) 9-264 42 88 A. Pellinen-Wannberg E-mail: ursi@intec.ugent.be ASSOCIATE EDITOR FOR ABSTRACTS P. Watson ASSOCIATE EDITORS P. Banerjee & Y. Koyama (Com. A) A. Sihvola (Com. B) S. Salous (Com. C) P-N Favennec (Com. D) D. Giri (Com. E) ASSOCIATE EDITOR FOR BOOK REVIEWS K. Schlegel S. Paloscia (Com. F) I. Stanislawska (Com. G) M.M. Oppenheim (Com. H) J. Baars (Com. J) E. Topsakal (Com. K) For information, please contact : The URSI Secretariat c/o Ghent University (INTEC) Sint-Pietersnieuwstraat 41, B-9000 Gent, Belgium Tel.: (32) 9-264 33 20, Fax: (32) 9-264 42 88 E-mail: info@ursi.org http://www.ursi.org The International Union of Radio Science (URSI) is a foundation Union (1919) of the International Council of Scientific Unions as direct and immediate successor of the Commission Internationale de Télégraphie Sans Fil which dates from 1913. Unless marked otherwise, all material in this issue is under copyright © 2012 by Radio Science Press, Belgium, acting as agent and trustee for the International Union of Radio Science (URSI). All rights reserved. Radio science researchers and instructors are permitted to copy, for non-commercial use without fee and with credit to the source, material covered by such (URSI) copyright. Permission to use author-copyrighted material must be obtained from the authors concerned. The articles published in the Radio Science Bulletin reflect the authors’ opinions and are published as presented. Their inclusion in this publication does not necessarily constitute endorsement by the publisher. Neither URSI, nor Radio Science Press, nor its contributors accept liability for errors or consequential damages. 2 The Radio Science Bulletin No 343 (December 2012)
Editorial Our Papers The problem of the propagation of a radio wave from a source over a lossy Earth is a classic problem, dating back at least to the work of Sommerfeld in 1909. As Tapan Sarkar, Walid Dyab, Mohammad Abdallah, Magdalena Salazar-Palma, M. V. S. N. Prasad, Silvio Barbin, and Sio Weng Ting demonstrate in their paper, this classic problem is of considerable current importance. This is because it provides new and significant insight into the science of electromagnetic propagation for cellular communications systems. The paper begins with a review of the history of this problem. Several controversies surrounding the existence and nature of various types of surfaces waves are explored in detail. The basic questions of what constitutes a surface wave, and under what conditions a surface wave is associated with such propagation, are addressed. The controversies surrounding such surface waves are resolved. This includes showing that the source of an error in Sommerfeld’s 1909 paper was not due to a sign error, as often claimed, but was rather due to a moresubtle mathematical issue. In a companion paper, the authors have shown that the electromagnetic fields associated with propagation in a cellular-communications cell decay over most of the cell with distance at a rate of 30 dB per decade, followed by a fringe region where the rate of decay is 40 dB per decade. This paper derives the fields that are responsible for this fading. Among other results, it is shown that the fields produced by a two-dimensional source, or by a line source, over an imperfectly conducting ground produce the initial fading rate. It is further shown that fields in the form of a Norton surface wave contribute only in the fringe region of the cell. A variety of experimental data related to the decay rate of fields over imperfectly conducting media is cited and examined in detail, and shown to support the theoretical conclusions. This includes classic experiments done in the 1930s specifically to investigate surface waves, as well as modern experiments with cellular communication systems. This leads to a clear and accurate physical representation of the fields associated with such systems. One of the most interesting consequences of this representation is that the basic propagation path losses for such systems are insensitive to the details of the propagation environment: a macro model is sufficient to accurately provide the basic path losses. This paper is important reading for anyone with an interest in either the classical problem of propagation over an imperfectly conducting medium, or in the propagation associated with modern cellular communication systems. Fundamental physics says that everything else being equal, the larger the baseline of a radio telescope, the higher its resolution. Achieving baselines larger than an appreciable fraction of the Earth’s diameter requires putting part of the radio telescope in space. The invited paper by N. S. Kardashev, Y. Y. Kovalev, and K. I. Kellermann describes RadioAstron, an Earth-space radio interferometer with an effective baseline that is more than a factor of 10 larger than what is possible on Earth. The paper begins with a review of the factors affecting the resolution of radio telescopes, and some comparisons with optical telescopes. This is followed by a brief introduction to radio interferometry. The use of independent oscillators located at the elements of an interferometer, along with remote recording of the data, are explained. These techniques remove two of the limitations to the baselines of very-long-baseline interferometry. Two earlier space-based long-baseline interferometers are reviewed. The development and specifications of RadioAstron are then reviewed. This instrument consists of a 10 m dish in space that works with a variety of Earth-based dishes in many different countries to provide a number of different observing opportunities. The spacecraft was launched in July 2011. The space dish is in a highly elliptical orbit, providing a baseline of as much as 350,000 km. The system operates in four bands, from 330 MHz to 22 GHz. The details of the hardware and the data system are given. The scientific goals of the project are reviewed, and early results are summarized. This paper provides a very nice review of space-based radio telescopes and RadioAstron. It also contains good resources for those seeking additional information. This paper is one of the invited Reviews of Radio Science from Commission J. The assistance of Ondrej Santolik and members of Commission J in bringing us this paper are gratefully acknowledged. Our Other Contributions Thanks to Kristian Schlegel, we again have two book reviews in this issue. One is from a Young Scientist, and both cover books that the reviewers found to be quite valuable. There are several calls for papers for important conferences for radio scientists in this issue. As readers may have noticed from the previous issue, we are now running the complete calls for papers as provided by the conferences. This should provide more information for our readers. We also have a report on a COSPAR session on “Global and Regional Representation of Ionospheric Peak Parameters for Space Weather Applications.” The summary The Radio Science Bulletin No 343 (December 2012) 3
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SCIENTIFIC COMMISSIONS Commission A
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Commission E : Electromagnetic Envi
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Commission J : Radio Astronomy Chai
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URSI MEMBER COMMITTEES AUSTRALIA Pr
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ALPHABETICAL INDEX AND CO-ORDINATES
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CARDOSO, Prof. J. R., Escola Polite
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FRØYSTEIN, Dr. H.A., Justervesenet
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KANELLOPOULOS, Prof. J., Division o
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MARTIN RODRIGUEZ, Prof. E., Faculta
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PIERRARD, Dr. V., Belgisch Instituu
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SKVOR, Prof. Z., Faculty of Electri
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8510, JAPAN, Tel. +81 75 383 2244,
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Information for authors Content The
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December 2012 - URSI

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