December 2012 - URSI

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provided of the results should be of interest to anyone using ionospheric models. This being the December issue, our usual updated material on the organization of URSI and key contact people within the Union is included. Best Wishes This issue should reach the URSI community around the middle of December. My very best wishes to all of our readers for most joyous holidays, and for a very happy, healthy, safe, and prosperous New Year! In Memoriam VLADIMíR FIALA 1938 - 2012 Vladimír Fiala, an internationally recognized space-plasma physicist, a former Chair of URSI Commission H (Waves in Plasmas), and a former President of the Czech National Committee of URSI, passed away on September 8, 2012, after a courageous fight against cancer. Dr. Fiala graduated from the Department of Mathematics and Physics of the Charles University in Prague in 1961. After doing postgraduate studies in the Lebedev Institute of Physics in Moscow with Alexander Gurevich, he received his PhD in space-plasma physics from the Geophysical Institute of the Czechoslovak Academy of Sciences in 1967. From 1967 to 1970, he worked in the Groupe de Recherches Ionospheriques/ CNRS in France with L. R. O. Storey, and then returned to Prague to work in the Geophysical Institute. He also lectured on space physics at Charles University. In addition, for several years he worked in France, Russia, and the United States in various space-research laboratories on long-term fellowships. In 1994, he received a Fulbright Research Award to work at the University of Minnesota. For the rest of his life, he then worked in the Department of Space Physics, Institute of Atmospheric Physics of the Academy of Sciences of the Czech Republic. Vladimir Fiala was elected Vice Chair of URSI Commission H at the 1993 Kyoto General Assembly. He became Chair of that Commission at the 1996 Lille General Assembly. From 1999 until 2008, he worked as the President of the Czech National Committee of URSI. The research interests of Vladimir Fiala were in theoretical space plasma physics, especially antenna-plasma interaction, propagation and excitation of plasma waves, and wave scattering by ionospheric irregularities. He significantly contributed to our understanding of the physics of probes and antennas in space plasmas. He researched and explained the behavior of magnetic and electric antennas in the context of planning or of data analysis for the FR-1 (France/NASA), Aktivnyi (USSR), CLUSTER (ESA), and OEDIPUS-C (Canada) missions. Dr. Fiala also took up and advanced the study of the probeantenna response to waves propagating close to plasma resonances. These included the oblique resonance occurring in anisotropic plasmas in the whistler mode, and the Langmuir-wave resonance in a drifting isotropic plasma. Vladimir Fiala was a keen proponent of international groups for working-level collaboration, as was evidenced by his organizational work in URSI. He championed and organized international group studies on diverse aspects of waves in space plasmas. A NATO Linkage Grant that he initiated led to the birth of the Resonance Cone Club consortium involving Russia, the Czech Republic, France, and Canada, which is just one example among many of his commitment to international scientific cooperation. Dr. Fiala was a talented scientist, and he loved his work. He had a gift for sharing his enthusiasm with younger colleagues, whom he was always ready to help to do good scientific work. His deep voice and his sense of humor impressed all those who had the privilege of working with him. Discussions with him were open, thoughtful, pleasant, and inspiring. He will be sorely missed. Edited by O. Santolik (Institute of Atmospheric Physics in Prague, Czech Republic; e-mail: os@ufa.cas. cz), Chair of URSI Commission H, with significant help from L. R. O. Storey and H. G. James 4 The Radio Science Bulletin No 343 (December 2012)
Physics of Propagation in a Cellular Wireless Communication Environment Tapan K. Sarkar W. Dyab, M. N. Abdallah M. Salazar-Palma M. V.S.N. Prasad S. Barbin, S. Weng Ting Abstract The objective of this paper is to illustrate from a physics standpoint the nature of the fields that carry energy from a transmitter to a receiver located over an imperfectly conducting Earth. In an accompanying paper [1], it was shown from both the theoretical (developed from the classical Sommerfeld attenuation function) and experimental points of view that the fields inside a cellularcommunication cell decay as 30 dB per decade, following a slow fading region. The 30 dB per decade region is followed by a region (in the fringe area) where the rate of decay is 40 dB per decade. This means that the fields 1.5 decay as 1 (where is the radial distance between 2 the transmitter and the receiver) and 1 , respectively, inside a cell. The first goal is to illustrate that Sommerfeld had no error in sign in his classic 1909 paper. However, while computing his asymptotic development of the branch-cut integral, Sommerfeld did not notice that beside the space wave, this contains the surface wave with a negative sign, which would cancel the residue of the pole. In other words, no surface wave can be generated from a pole that is a part of the original Sommerfeld solution for radiation from a dipole operating over an imperfectly conducting ground. Other type of waves, e.g., Norton’s surface wave and a radiation 1.5 field that decays as 1 , are part of the ground wave. They can be derived from the same Sommerfeld attenuation function, but using different types of approximations. As already mentioned, Norton’s surface wave and the radiation 1.5 field (decaying as 1 ) are a part of the solution. These points were illustrated in an accompanying paper [1]: here, we focus on the physics of these waves. We also explain what the mathematical characteristics of a surface wave are, as there is a lot of confusion in the usage of the same word for different types of waves. The goal of this paper is hence to develop an understanding of the physics associated with radiating fields that decay with a rate of 30 dB per decade with distance, and with an emphasis on the following phenomena: 1. To illustrate that radiation fields emanating from a twodimensional source and associated with the launching of a true surface wave are responsible for producing a field that decays as 30 dB per decade. This type of field can also be generated from a line source located over an imperfectly conducting ground. 2. To illustrate that radiation fields in the form of Norton’s surface wave contribute only in the fringe areas of the cells, where the fields decay as 40 dB per decade. 3. To illustrate that the error in Sommerfeld’s classical paper of 1909 had nothing to do with an error in sign. He did not consider the effect of the occurrence of a pole near the saddle point in his asymptotic expansion. In other words, the poles were not located on the proper Riemann sheet. The popular belief that he made an error in sign in his paper is indeed a myth! 4. To illustrate that the electromagnetic field produced in a cellular communication system (where the dipole constituting the base-station antenna is placed at a given height over the imperfectly conducting surface of the Earth) is due to an infinite set of images starting at the location of the image of the first point of the transmitting antenna and extending to negative infinity, resulting in a line source. This will be illustrated by both theoretical and experimental data. This further illustrates that ray tracing is not the appropriate tool to use in predicting the fields near the ground. Tapan K. Sarkar, Walid Dyab, and Mohammad N. Abdallah are with the Department of Electrical Engineering and Computer Science, Syracuse University, Syracuse, New York 13244-1240, USA; e-mail: tksarkar@syr.edu; http://lcs.syr. edu/faculty/sarkar/; Magdalena Salazar-Palma is with the Dept. of Signal Theory & Communications, Universidad Carlos III de Madrid, Avenida de la Universidad, 30, 28911 Leganés, Madrid, Spain; e-mail: salazar@tsc.uc3m.es; M. V. S. N. Prasad is with the National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi-110012, India; e-mail: mvsnprasad@gmail.com; Silvio Barbin is with the Departamento de Engenharia de Telecomunicações e Controle Escola Politécnica da Universidade de São Paulo, São Paulo, Brazil; e-mail: barbin@usp.br; Sio Weng Ting is with the Department of Electrical Engineering and Computer Science, University of Macau, Av. Padre Tomas Pereira, Taipa, Macau, China (CIE); e-mail: tonyting@umac.mo. The Radio Science Bulletin No 343 (December 2012) 5
Page 1 and 2: Radio Science Bulletin ISSN 1024-45
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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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