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Antennas and Propagation, IEEE Transactions on

Issue 4 • Date July 1966

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  • [Front cover and table of contents]

    Publication Year: 1966 , Page(s): 0
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  • Sequel to "Reciprocity relations in a compressible plasma"

    Publication Year: 1966 , Page(s): 519
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  • [Back cover]

    Publication Year: 1966 , Page(s): c4
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  • RF propagation and absorption measurements in a magneto-plasma near electron cyclotron resonance

    Publication Year: 1966 , Page(s): 513 - 515
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  • Microwave propagation over mountain-diffraction paths

    Publication Year: 1966 , Page(s): 489 - 496
    Cited by:  Papers (5)
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    An experimental study was undertaken to obtain a more complete picture of wide-band transmission via microwave propagation over mountain-diffraction paths. Such paths are characterized by obstacles of irregular shape, and pathlength very large compared to wavelength. Swept-frequency transmission was used to provide a record of signal-level variations with time and frequency on two different paths. Other observations included polarization dependence, spatial variation, and direct comparison with repeater-relayed signals. The two paths were selected on the basis of obstacle shape; in one case a conical mountain peak, in the other a cylindrically-topped ridge. While the gross features of the data were in agreement with conventional theory, significant detailed departures were noted on the mountain peak path. It was concluded that, in general, the effects of a nonuniform transverse obstacle profile must be taken into account in microwave diffraction. A comparison of data from the two paths supported this conclusion. The "repeater model" of diffraction was also examined and found to be of dubious value for the paths in question. View full abstract»

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  • Doppler tracking loops for the active adaptive antenna array system

    Publication Year: 1966 , Page(s): 502 - 503
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  • Self- and mutual admittances of two identical circular loop antennas in a conducting medium and in air

    Publication Year: 1966 , Page(s): 440 - 450
    Cited by:  Papers (19)  |  Patents (7)
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    The normalized self- and mutual admittances of two identical bare circular loop antennas have been evaluated when the loops are immersed in either air or an infinite homogeneous conducting medium. By decomposing the voltage and current into symmetric and antisymmetric components, the simultaneous integral equations for the distribution of current along the loop have been converted into a single integral equation similar to that for the isolated circular loop antenna which has already been studied. The computed results are presented graphically. The measured results are in good agreement with theory. View full abstract»

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  • An experimental investigation of currents on a yagi array of slot antennas on planar and curved surfaces

    Publication Year: 1966 , Page(s): 451 - 454
    Cited by:  Patents (1)
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    The slot Yagi-type antenna array is studied in detail on planar and curved surfaces. Current magnitude and phase associated with individual elements are measured for various element lengths and element spacings. Termination effects are studied for an eighteen-element array with elements one-third of a wavelength in length and with various element spacings. Comparison is made with and support given to recent work integrating array and surface wave theories. View full abstract»

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  • The use of the convolution thereom and the generalized sampling thereom in evaluating arbitrary arrays

    Publication Year: 1966 , Page(s): 503 - 505
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  • Multiple knife-edge diffraction of microwaves

    Publication Year: 1966 , Page(s): 480 - 489
    Cited by:  Papers (82)
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    The paper discusses a simplified solution to the problem of multiple diffraction of microwaves over knife-edge obstacles. The path loss is obtained directly and quickly by alignment of distances and heights, adequately selected from a path profile. A theoretical study shows good agreement between the simplified approach and a complete mathematical analysis made by G. Millington in 1962. When the diffraction loss reaches a maximum which might be in excess of 50 dB, the approximate value exceeds the theoretical one by 2 to 5 dB. Predictions are in good agreement, too, with the results of experiments conducted both in France and in the United States. Out of ten examples reported in the paper, nine indicate an error equal or smaller than 3 dB. View full abstract»

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  • A 3 Gc/s scale model of a submerged VLF antenna using lossy ceramic powder

    Publication Year: 1966 , Page(s): 507 - 509
    Cited by:  Papers (1)
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  • Coupled waveguide antennas

    Publication Year: 1966 , Page(s): 416 - 422
    Cited by:  Papers (2)  |  Patents (1)
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    A structure consisting of two coupled waveguides is proposed as a leaky-wave antenna. The analysis of this device is based on coupled-mode theory. Previous coupled-mode treatments are extended, since radiative loss is not neglected and the asymmetry of the structure is taken into account. Two cases are considered: the coupling parameter constant with distance z along the antenna and the coupling as a function of z . In both, the radiative attenuation is maintained constant. It is found that the first case permits two "normal modes" to propagate and, if both modes are excited, the patterns may be superposed to produce desirable overall results. An example is given of an approximation to a pencil beam pattern. By means of the second method, essentially any of the common excitation functions may be produced. An example is given of an antenna to achieve a cosine-on-a-pedestal excitation. Experimental results are given and compared to theory. Suggestions are presented for further work. View full abstract»

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  • Surface mode propagation along an array of dielectric rods with all elements excited identically

    Publication Year: 1966 , Page(s): 510 - 511
    Cited by:  Papers (1)
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  • On scattering of waves by the infinite grating of elliptic cylinders

    Publication Year: 1966 , Page(s): 465 - 480
    Cited by:  Papers (1)
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    The functional equation derived previously for the scattering by a grating of relatively arbitrary elements is applied to elliptic cylinders. This specifies the problem in terms of an infinite set of linear algebraic equations involving the scattering coefficients of an isolated elliptic cylinder and certain combinations of Schlömilch series. General approximations are obtained by series expansions, and by truncating the sets of equations; we consider both polarizations ( E or H parallel to the elements), arbitrary angle of incidence, and arbitrary spacing. Explicit results are given for ellipses that are small compared to the wavelength. View full abstract»

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  • Radiation pattern synthesis for circular aperture horn antennas

    Publication Year: 1966 , Page(s): 434 - 440
    Cited by:  Papers (17)
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    A set of radiation pattern functions, suitable for synthesis of radiation patterns from circular aperture horn antennas, is obtained by assuming an aperture distribution consisting of the fields of cylindrical waveguide modes. A technique is presented for using a linear combination of the radiation pattern functions to approximate a desired radiation pattern. Linear combinations of the radiation pattern functions resulting in maximum secondary gain, when used to illuminate a paraboloidal antenna, are obtained empirically. Using spherical wave theory, maximum performance theoretically obtainable from an antenna is derived as a function of the aperture size of the feed system; the feed efficiency resulting from these theoretical limits on performance is compared to the feed efficiency of patterns obtainable from circular aperture horn antennas, and to experimental results of attempts to realize optimum circular aperture horn patterns. View full abstract»

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  • On the calculation of the ground wave attenuation factor at low frequencies

    Publication Year: 1966 , Page(s): 515 - 517
    Cited by:  Papers (7)
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  • Optimization of linear arrays for broadband signals

    Publication Year: 1966 , Page(s): 422 - 427
    Cited by:  Papers (7)
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    The effect of broadband signals on the far-zone field of long arrays is investigated in terms of the energy radiation pattern. A generalized directive gain is introduced which depends on the signal spectrum. With maximum directivity as a criterion it is shown that the problem of optimizing a long isotropic array with respect to a given signal can be associated with a classical eigenvalue problem. The concept of array-bandwidth is introduced. Computed curves for directivity and directive gain are given in terms of this parameter and signal bandwidth. It is shown that while little improvement in directivity is achieved by optimizing the distribution coefficients of an array, a substantial reduction in sidelobe level is obtained when the signal bandwidth is comparable to the array bandwidth. View full abstract»

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  • Electric dipole radiation through a finite conical plasma sheath

    Publication Year: 1966 , Page(s): 428 - 433
    Cited by:  Papers (3)
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    The ionized boundary layer that forms around a reentry vehicle is represented by a conical sheath having a surface impedance which is determined by the integrated electron density in the boundary layer. This cone can support surface currents that are induced in it by a Hertzian dipole antenna situated on its axis. The radiation pattern of such a structure at wavelengths short compared to the slant height is calculated by a perturbation technique. The calculation holds when the surface conductivity of the sheath varies linearly with distance from the apex of the cone. Plots are presented showing the effects of sheath strength, slant height, and antenna frequency on the patterns. View full abstract»

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  • Concerning lossy, compressible, magneto-ionic media-General formulation and equation decoupling

    Publication Year: 1966 , Page(s): 497 - 501
    Cited by:  Papers (5)
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    The governing equations for electromagnetic phenomena in lossy, compressible, magneto-ionic media are formulated in terms of a newly introduced compressivity tensor. The matrix forms of both the permittivity tensor and the compressivity tensor are given. From the new governing equations, a three-dimensional vector wave equation and a dispersion equation are derived. In a source-free region, a set of three simultaneous wave equations in the longitudinal components of the electric and magnetic fields and in the pressure distribution can be written. These equations can be decoupled in the lossless case by effecting a transformation. The required transformation matrix and the resulting uncoupled, second-order, differential equations are given. Formulas for the determination of the transverse components of the electric and magnetic fields are also derived. View full abstract»

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  • Network representation for spherical waves in a compressible plasma

    Publication Year: 1966 , Page(s): 517 - 519
    Cited by:  Papers (1)
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  • Radar echo variations of a large rough sphere

    Publication Year: 1966 , Page(s): 455 - 460
    Cited by:  Papers (1)
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    The effect of surface roughness on the radar backscattering cross section of a perfectly conducting nominally spherical target is examined by applying the Kirchhoff method. It is shown that, for the type of roughness and sphere size to which the Kirchhoff method is applicable, the standard deviation of the cross section increases with frequency according to the law 2\sqrt {2} \sigma _{0} k\zeta until the first Fresnel zone reduces in size to the scale length of the roughness. At this point a knee in the curve occurs and its further course is determined by a more detailed statistical description of the surface. Here \sigma _{0} is the nominal cross section, \zeta is the standard deviation of the surface height h and k=2\pi/\lambda , where \lambda is the wavelength. The average cross section is shown to be given by \sigma _{0}[1+0 {(kh)^{3}}] . Some experimental results are reported which support the theoretical conclusions. View full abstract»

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  • Swept frequency measurement of water-drop diameter

    Publication Year: 1966 , Page(s): 509 - 510
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  • TE-wave scattering by a dielectric cylinder of arbitrary cross-section shape

    Publication Year: 1966 , Page(s): 460 - 464
    Cited by:  Papers (97)
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    The theory and equations are developed for the scattering pattern of a dielectric cylinder of infinite length and arbitrary cross-section shape. The harmonic incident wave is assumed to have its electric vector perpendicular to the axis of the cylinder, and the fields are assumed to have no variations along this axis. Although some investigators have approximated the field within the dielectric body by the incident field, a more accurate solution is obtained here by treating the field as an unknown function which is determined by solving a system of linear equations. Scattering patterns obtained by this method are presented for dielectric shells of circular and semicircular cross section, and for a thin plane dielectric slab of finite width. The results for the circular shell agree accurately with the exact classical solution. The effects of surface-wave excitation and mutual interaction among the various portions of the shell are included automatically in this solution. View full abstract»

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  • Plane wave transmission and reflection coefficients for lossy inhomogeneous plasmas

    Publication Year: 1966 , Page(s): 511 - 513
    Cited by:  Papers (2)
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  • Directive gains of nonuniformly spaced arrays

    Publication Year: 1966 , Page(s): 505 - 507
    Cited by:  Papers (1)
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Aims & Scope

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

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Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung