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Antennas and Propagation Magazine, IEEE

Issue 4 • Date Aug. 1991

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Displaying Results 1 - 8 of 8
  • The Galileo mission to Jupiter and Doppler wind measurements

    Publication Year: 1991 , Page(s): 7 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1186 KB)  

    The results of previous atmospheric entry missions are reviewed, including the Pioneer Venus, Venera, and Vega missions. The Galileo mission is then described. The dual-vehicle (probe and orbiter) spacecraft was launched in October 1989 and will reach Jupiter in December 1995. The spacecraft and its hardware are described. The method used to measure the variation of wind velocities with altitude in the upper Jovian atmosphere, a key objective of the mission, is examined. The radio propagation environment of that atmosphere and its effects on the probe signal are discussed. Other errors that can affect the frequency of the received telemetry and thereby reduce the accuracy of the recovered wind profile are considered.<> View full abstract»

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  • Plotting satellite antenna radiation patterns

    Publication Year: 1991 , Page(s): 18 - 20
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (231 KB)  

    Approaches for visualizing satellite antenna radiation patterns are presented. Gain-level contours drawn over a geographical map give the clearest quantitative information. A three-dimensional surface plot displays the qualitative shape of the radiation pattern more naturally. Giving a 3-D effect to level contours allows quantitative and qualitative information to be combined, but it can only be used to complement the other plots. These methods of visualization all use plotters to produce their images. The hidden-point algorithm for 3-D contour plots is described.<> View full abstract»

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  • Will gravity-wave communication be possible? (gravity read gravitational)

    Publication Year: 1991 , Page(s): 21 - 23
    Cited by:  Papers (1)  |  Patents (2)
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    Evidence for the existence of gravitational waves is briefly reviewed, and techniques for generating and receiving gravitational waves are considered. It is concluded that the physical limitations encountered and the elusiveness of the waves themselves make their application for communication remote.<> View full abstract»

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  • What on earth happened to the Central Radio Propagation Laboratory (CRPL)?

    Publication Year: 1991 , Page(s): 24 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (385 KB)  

    The formation and evolution of what was known, for the 20 year period starting shortly after World War 2, as the Central Radio Propagation Laboratory (CRPL) of the National Bureau of Standards (NBS) is traced. NBS formed the Inter-Service Radio Propagation Laboratory (IRPL) in the summer of 1942 to provide the armed services with radio communication research services. IRPL was replaced, in May 1946, by the CRPL. In 1965, the Environmental Science Services Administration (ESSA) was formed by merging the Weather Bureau, the Coast and Geodetic Survey, and the CRPL. In ESSA, CRPL, now named the Institute for Telecommunication Services and Aeronomy (ITSA), joined three sister institutes from the Weather Bureau and the Coast and Geodetic Survey, namely the Institutes for Atmospheric Science, for Oceanography, and for Earth Sciences, forming the ESSA Institutes for Environmental Research. Following this move, the telecommunication and environmentally oriented components of ITSA began to move apart. Activities pursued by these two components and their further evolution in the ensuing decades are summarized.<> View full abstract»

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  • Complex image theory-revisited

    Publication Year: 1991 , Page(s): 27 - 29
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (213 KB)  

    A quasi-historical sketch of complex image theory for low-frequency electromagnetic fields is presented from a personal perspective. Studies using complex image theory, on launching TM (transverse magnetic) modes into the Earth-ionosphere waveguide from a horizontal insulated cable, grounded at the end points, are described. Subsequent implementation and further development of the concept by other authors is summarized.<> View full abstract»

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  • Lorenz or Lorentz? [Addendum]

    Publication Year: 1991 , Page(s): 56
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    Summary form only given, as follows. This short (and modest) note has generated a number of reactions! The first one is the publication, in the present issue, of an interesting note by Dr. Sihvola. It concerns the paternity of another Lorenz-Lorentz common effort. The second reaction is a message by Professor J. Bach Andersen, Vice-President of URSI, who lets the author know that an interesting review of Ludwig Valentin Lorenz' career and scientific work, written by M. Pihl, can be found in Volume 1 of Electromagnetic Theory arul Antennas. This book, published by Pergamon Press in 1963, contains the proceedings of the 1962 Symposium on Electromagnetic Theory, the well-known series organized by URSI's Commission B. Pihl's article, some 10 pages long, mentions that Lorenz was, indeed, the first physicist to introduce retarded potentials ... the author would like to make use of the present addendum to mention that "Kirchhoff" was misprinted in my original note. View full abstract»

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  • Lorenz-Lorentz or Lorentz-Lorenz?

    Publication Year: 1991 , Page(s): 56
    Cited by:  Papers (1)
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    Inspired by the legitimate note by Professor Van Bladel [l], about the paternity of retarded potentials in electromagnetics, and, by the way, also the Lorenz gauge, I take the liberty to continue the discussion, and to further restore some of Lorenz's honor (and divest that from Lorentz, but on the other hand, he really cannot be claimed to be short of fame; and also, let it be clear that my admiration for him is not diminished). View full abstract»

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  • Unusual boundary conditions at an interface (EM theory)

    Publication Year: 1991 , Page(s): 57 - 58
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    The derivation of electromagnetic boundary conditions at an interface by applying Gauss' divergence theorem to a flat pillbox or Stokes' curl theorem to a narrow contour is considered for two types of unusual boundary condition. One is an electric field discontinuity and the other is a double layer of current. It is suggested that the usual continuity proofs, based on pillboxes and contours of vanishing dimension, must be handled with care. Specifically, a ' delta function' behavior of certain components along the normal is possible.<> View full abstract»

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