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IEEE Transactions on Antennas and Propagation

Issue 6 • November 1978

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Displaying Results 1 - 25 of 35
  • [Front cover and table of contents]

    Publication Year: 1978, Page(s): 0
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    Freely Available from IEEE
  • GTD analysis of the radiation patterns of conical horns

    Publication Year: 1978, Page(s):774 - 778
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (397 KB)

    The far-field radiation patterns of conical horns of arbitrary flare angles excited in theTE_{11}mode are obtained employing the geometric theory of diffraction (GTD) based on the theory of Kouyoumjian and Pathak [3] and the slope diffraction technique [4]. The analysis presented enables one to predict accurately radiation patterns over the main beam, near and far sidelobes, and the bec... View full abstract»

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  • Loaded horizontal antenna over an imperfect ground

    Publication Year: 1978, Page(s):789 - 796
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (558 KB)

    The Fresnel reflection coefficient technique is employed to establish anE-field integral equation for the antenna current. A resistive loading of the formLambda(x) = Lambda_{0}/(1 - |x|/L)is used to load the antenna. An optimization technique is discussed for determining the value of critical loadingLambda_{0}^{c}, which enforces a traveling wave current on the ant... View full abstract»

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  • Bistatic clutter measurements

    Publication Year: 1978, Page(s):801 - 804
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (382 KB)

    Empirical data have been obtained from which estimates of the bistatic reflection coefficientsigma_{0}have been determined. Measurements were made on two terrain types (grassy terrain and an area of tall weeds and rough ground) at low grazing bistatic angles of70deg, 75deg, 80deg, and85deg, and0degto180degazimuth angle. The terrain was illumin... View full abstract»

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  • Forward scattering from cylinders of triangular cross section

    Publication Year: 1978, Page(s):849 - 850
    Cited by:  Papers (14)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (195 KB)

    The induced-field ratios (IFR) of conducting cylinders of a triangular cross section have been calculated. When the width of the cross-section is in the range of 1-2 wavelengths, theE-wave IFR's are substantially less than the corresponding values for square or circular cross sections. From the standpoint of RF aperture blocking of a reflector antenna, the triangular cross section thus ... View full abstract»

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  • The effect of slowly varying surface errors in large millimeter wave antennas: A practical verification in the Itapetinga 45-ft reflector

    Publication Year: 1978, Page(s):854 - 857
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (489 KB)

    The aperture efficiency of the 45-ft Itapetinga reflector was found to be about 50 percent atlambda = 7mm. The reflector surface panels were mechanically measured in 2664 points displaying the presence of slowly varying errors that negligibly effect the aperture efficiency. We confirm that the reflector's aperture efficiency seems to be predictable from mechanical measurements of the su... View full abstract»

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  • Telescope surface measurement with two feeds

    Publication Year: 1978, Page(s):857 - 860
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (381 KB)

    A method is suggested where a reference feed is fixed at the telescope focus, and a second feed has a lateral offset and scans the focal plane. The telescope tracks a celestial radio source, and the receiver measures the phase difference at the two feeds and their (voltage) amplitude ratio. A set of coordinate transformations is applied, after which the surface deviationssigmafrom a par... View full abstract»

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  • Broad-band VSWR measurements of a Cassegrain antenna

    Publication Year: 1978, Page(s):865 - 867
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (319 KB)

    Broadband VSWR measurements are reported on a smallF-number Cassegrain antenna. Cyclical variations of VSWR between 1.00 and 1.25 with a 350-MHz frequency interval between unity VSWR values were observed over the 8.5-12.4 GHz frequency range. These variations correspond to a change in the power transmission ratio of 1.231 percent between the unity and 1.25 values of VSWR. View full abstract»

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  • Directional properties of nonplanar aperture-type antennas

    Publication Year: 1978, Page(s):867 - 870
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (401 KB)

    Theoretical analysis of the directional properties of a large nonplanar aperture-type antenna and experimental results thereon are given and discussed. Two kinds of nonplanar parabolic cylindrical apertures have been considered: one having a curvature in theE- plane and the other in theH-plane. In the experiments, such nonplanar apertures were cut at the mouth of a suitable s... View full abstract»

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  • Range-testing a conical logarithmic spiral antenna for a dual-polarized riometer

    Publication Year: 1978, Page(s):870 - 872
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (333 KB)

    The off-axis axial ratios and the radiation patterns of conical log spiral models have been examined experimentally at a single frequency with the objective of finding a circularly polarized antenna of small physical height, suitable for use in decametric dual-polarized riometers. Truncation of a narrow-cone-angle spiral produced rapid axial-ratio degradation below0.75 lambdaheight in t... View full abstract»

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  • Comments on "Superconducting superdirectional antenna arrays

    Publication Year: 1978, Page(s): 891
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (115 KB)

    The author points out that the approximate results given for linear arrays in the above paper (see ibid., vol.25, p.885-7 (1977)) are somewhat misleading, and shows that the array factors at least can be written exactly View full abstract»

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  • [Back cover]

    Publication Year: 1978, Page(s): c4
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    Freely Available from IEEE
  • Rain-induced attenuation at 36 GHz and 110 GHz

    Publication Year: 1978, Page(s):873 - 875
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Results are presented of the ratios of the rainfall attenuation measured simultaneously along a common path at 36 GHz and 110 GHz. These ratios agree well with the theoretically derived ratios assuming the Laws-Parsons distribution. View full abstract»

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  • Partially adaptive array techniques

    Publication Year: 1978, Page(s):823 - 833
    Cited by:  Papers (51)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    The selection of auxiliary elements for partially adaptive antenna arrays for the purpose of optimizing performance in a multiple narrow-band jammer environment is studied. An explicit solution for the two-jammer problem is derived. This case is sufficient to illustrate the interaction of multiple jammers and at the same time affords a degree of understanding of more complex problems. Computer sol... View full abstract»

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  • Digital error rate performance of active phased array satellite systems

    Publication Year: 1978, Page(s):833 - 842
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB)

    A model for a multiple spot beam digital satellite employing an active phased array antenna with frequency reuse is proposed and applied to study the power limited down-link bit error rate performance. Since the power amplifier preceding each antenna element is generally nonlinear, intermodulation distortion is produced among the various spot beams, degrading performance. Expressions for the bit e... View full abstract»

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  • Properties of the forward-scattered incoherent radiation through intense precipitation

    Publication Year: 1978, Page(s):804 - 809
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (536 KB)

    Incoherent radiation generally results from a first- or multiple-order scattering process; the first-order process is studied here with particular regard to its effects on large-capacity radio channels. It is shown, in fact, that the first-order scattering cannot be taken into account simply as noise because it generates fluctuations and nonlinearities of the channel transfer characteristic. In pa... View full abstract»

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  • On the possibility of "Real ray" tracing when the ray direction is complex

    Publication Year: 1978, Page(s):895 - 898
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (368 KB)

    When the ray direction is complex, there exists no real trajectory along which the partial differential "equation of the eikonal" reduces to a system of ordinary differential (ray) equations. Such problems can be solved either by tracing complex rays or tracing a family of phase trajectories simultaneously. View full abstract»

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  • Multiple beam synthesis of low sidelobe patterns in lens fed arrays

    Publication Year: 1978, Page(s):883 - 886
    Cited by:  Papers (5)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (384 KB)

    Low sidelobes in lens fed multibeam arrays present some unique problems. The technique of synthesizing low sidelobe patterns by the superposition of multiple orthogonal beams offers several advantages, particularly in lens fed arrays. It is shown that the Taylor line-source distribution is a superposition of multiple orthogonal beams. It is further shown that use of only three beams provides patte... View full abstract»

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  • Active microwave sensing of the Earth's surface--A mini review

    Publication Year: 1978, Page(s):843 - 849
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (856 KB)

    Radar has been used for remotely sensing the surface of the land and sea since the middle of World War II, but only since the mid-1960's has this technique become widely used for civil purposes. The nature of radar backscatter and theoretical models that have been used to describe it are briefly described. The state of knowledge of radar return from both land and sea is summarized. The principal r... View full abstract»

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  • An integral equation formulation of the direct scattering problem for an inhomogeneous slab

    Publication Year: 1978, Page(s):797 - 800
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (328 KB)

    A numerical technique based on an integral equation scheme is developed for solving the direct scattering problem for an inhomogeneous slab. The integral equation is derived, using the induced current concept and the Green's function technique. The numerical method of solving the integral equation is presented. The method is proved to be numerically satisfactory and is applied to the slab of speci... View full abstract»

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  • High-frequency fields excited by a line source located on a perfectly conducting concave cylindrical surface

    Publication Year: 1978, Page(s):757 - 767
    Cited by:  Papers (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (824 KB)

    Alternative representations are obtained for the high-frequency surface field excited on a perfectly conducting concave circular cylinder by an axial magnetic line current located on the surface. Included are ray-optical, canonical integral, whispering gallery mode, and near-field formulations, and various combinations of these. Asymptotic evaluations in different parameter ranges lead to results ... View full abstract»

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  • Synthesis and optimization for arrays of nonparallel wire antennas by the orthogonal method

    Publication Year: 1978, Page(s):886 - 891
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    The orthogonal method is presented for synthesis and optimization problems of arrays of straight nonparallel thin-wire antennas. First, by the moment method, the far-zone field and the performance indices of the away are represented by expressions useful for applying the orthogonal method. By a procedure similar to the Gram-Schmidt method, the far-zone field and the indices of the array are modifi... View full abstract»

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  • Mutual admittance of slots on a cone: Solution by Ray technique

    Publication Year: 1978, Page(s):768 - 773
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (480 KB)

    An approximate asymptotic Green's function for the surface magnetic field due to a magnetic dipole on a general convex conducting surface is developed. Based largely on the classical work of V. A. Fock and the current GTD recipes, this solution is presented in a form that admits ray interpretations, and can be simply evaluated. We apply the Green's function to calculate the mutual admittance betwe... View full abstract»

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  • Temporal spectra of atmospheric amplitude scintillations at 110 GHz and 36 GHz

    Publication Year: 1978, Page(s):875 - 877
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (320 KB)

    Experimental results of the ratio of the atmospheric amplitude scintillation spectra at 110 GHz and 36 GHz and the amplitude coherences at these two frequencies are presented. Both results agree well with the theoretical predictions. View full abstract»

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  • Design of superdirective arrays with high radiation efficiency

    Publication Year: 1978, Page(s):819 - 823
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (440 KB)

    Superdirective arrays have been considered unrealizable due to the high elemental currents required and their sensitivity to small variations in amplitude and phase. A new approach to superdirective array design based on polynomials which optimize radiation efficiency has been devised. An example of the optimization procedure is given for a 2-wavelength 11-element array, and the sensitivities of r... View full abstract»

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IEEE Transactions on Antennas and Propagation includes theoretical and experimental advances in antennas.

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Editor-in-Chief                                             Danilo Erricolo