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Antennas and Propagation, IEEE Transactions on

Issue 4 • Date July 1979

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  • [Front cover and table of contents]

    Publication Year: 1979 , Page(s): 0
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    Freely Available from IEEE
  • Correction to "Electromagnetic modeling of composite wire and surface geometries"

    Publication Year: 1979 , Page(s): 570
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (91 KB)  

    First Page of the Article
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  • [Back cover]

    Publication Year: 1979 , Page(s): c4
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    Freely Available from IEEE
  • Pattern measurements of a low-sidelobe horn antenna

    Publication Year: 1979 , Page(s): 551 - 555
    Cited by:  Papers (6)
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    The power pattern of a corrugated horn antenna designed for low sidelobes was measured to levels 90 dB below the main beam maximum in both the E - and H -planes. The measured patterns were found to be in good agreement with theoretical predictions. View full abstract»

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  • A combined-source solution for radiation and scattering from a perfectly conducting body

    Publication Year: 1979 , Page(s): 445 - 454
    Cited by:  Papers (46)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    A combined-source solution is developed for electromagnetic radiation and scattering from a perfectly conducting body. In this solution a combination of electric and magnetic currents, called the combined source, is placed on the surface S of the conducting body. The combined-source operator equation is obtained from the E -field boundary-value equation. It is shown that the solution to this operator equation is unique at all frequencies. The combined-field operator equation also has a unique solution, but it is not directly applicable to the aperture radiation problem. The H -field and E -field operator equations fail to give unique solutions at frequencies corresponding to the resonant frequencies of a cavity formed by a hollow conductor of the same shape. The combined-source operator equation is solved by the method of moments. The solution, valid for a three-dimensional closed surface S , is then applied to a surface of revolution. Examples of numerical computations are given for a sphere, a cone-sphere, and a finite circular cylinder. View full abstract»

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  • A novel radar array and its imaging properties

    Publication Year: 1979 , Page(s): 567 - 570
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    A novel radar array providing resolution superior to any other antenna configuration with the same physical aperture is described. Application of the new array to a localized imaging system suitable for real-time operation is simulated, and its resolution and depth of field properties ate compared with those of a crossed array and the conventional filled array antenna. Substantial savings in weight, cost, and complexity are offered by the proposed configuration. View full abstract»

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  • Preliminary testing of teflon as a hydrophobic coating for microwave radomes

    Publication Year: 1979 , Page(s): 555 - 557
    Cited by:  Papers (1)
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    Transmission loss measurements under conditions of simulated rainfall and observed weatherability suggest that Teflon may be a suitable hydrophobic coating for microwave radomes. Teflon performance is compared with fumed silicone dioxide (FSD) and HMOD4, coatings which have been the subject of an earlier detailed study. View full abstract»

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  • Small antenna location synthesis using characteristic modes

    Publication Year: 1979 , Page(s): 530 - 531
    Cited by:  Papers (21)
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    It is shown that the efficiency of a small antenna can be substantially increased by properly locating it on its support structure. Characteristic modes are used to determine the optimum location and frequency. View full abstract»

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  • Useful coordinate transformations for antenna applications

    Publication Year: 1979 , Page(s): 571 - 574
    Cited by:  Papers (28)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    General coordinate transformations which are commonly encountered in many antenna applications are presented. Neither the feed coordinates nor the far-field pattern coordinates in general coincide with the antenna coordinates. Transformations discussed allow one to relate the spherical and Cartesian components of one system to the spherical and Cartesian compoents of the other system. In particular, attempts are made to use unified notations to assist the reader in a straightforward application of the transformations. View full abstract»

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  • A measurement system and analysis procedure for determining the spatial phase structure function of ionospherically reflected waves

    Publication Year: 1979 , Page(s): 500 - 507
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    A 40-km sparse high-frequency (HF) receiving array is described which was used to measure the instantaneous phase at eight sites within the array of a pulsed 9-MHz transmission from Boulder, CO, to the Philadelphia, PA, area. The experimental program was designed to produce data on the statistical properties of the phase-front of a wave after passage through the ionosphere for the purpose of assessing the design problems of an array large enough to focus a 1-km cross-section beam at transoceanic distance (array size the order of 100 km). The problem of the effect of phase-front fluctuations due to turbulence induced scattering and internal ionospheric waves is formulated. The adaptive beamforming and scanning program of the Valley Forge Research Center, University of Pennsylvania, Philadelphia, is expected to yield solutions to this problem through self-cohering procedures. The nature of the desired measurements and a measuring system for accomplishing the task are also described. View full abstract»

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  • Synthesis of a small parabolic grid receiving antenna

    Publication Year: 1979 , Page(s): 524 - 527
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    The purpose of a paraboloidal receiving antenna is to concentrate an incoming electromagnetic field in the region of the geometrical focus, so that the strength of the field there is increased by the reflector focusing action. It is shown how, starting with two reflector grids symmetrically located in an eight-element grid paraboloid, this increase of the field along the axis is achieved, as the number of grid elements is increased to fill the paraboloid. View full abstract»

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  • Multibeam synthetic aperture radar for global oceanography

    Publication Year: 1979 , Page(s): 535 - 538
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    A single-frequency multibeam synthetic aperture radar concept for large swath imaging desired for global oceanography is evaluated. Each beam illuminates a separate range and azimuth interval, and images for different beams may be separated on the basis of the Doppler spectrum of the beams or their spatial azimuth separation in the image plane of the radar processor. The azimuth resolution of the radar system is selected so that the Doppler spectrum of each beam does not interfere with the Doppler foldover due to the finite pulse repetition frequency of the radar system. View full abstract»

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  • Polarizabilities of rectangular dielectric cylinders and of a cube

    Publication Year: 1979 , Page(s): 557 - 560
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB)  

    A previously derived integral representation technique is used to calculate the polarizability of a rectangular dielectric cylinder and of a cube. For the cylinder the results agree well with those of Mei and Van Bladel and for the cube they agree satisfactorily with those of Herrick and Senior. The method is applicable to a wide variety of shapes. View full abstract»

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  • Slot-monopole antenna system for energy-density reception at UHF

    Publication Year: 1979 , Page(s): 485 - 489
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    A new type of energy-density antenna is proposed for mobile telephony in the 800-1200-MHz range using a slot-monopole antenna (SMA) configuration. To mount the antenna on a mobile two orthogonally crossed slot antennas backed by a shallow cavity placed on the roof were found to be most suitable for receiving the magnetic field components, whereas a monopole attached to the base of the cavity and designed as a sleeve antenna is utilized to probe the electric field component. A prototype of the SMA system is manufactured, and its dimensions and design characteristics are presented. The radiation pattern, the input impedance of each of the three sections of the antenna system, and the isolation characteristics between all the sections of the SMA are measured and discussed. View full abstract»

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  • Off-axis cross-polarization and polarization efficiencies of reflector antennas

    Publication Year: 1979 , Page(s): 460 - 466
    Cited by:  Papers (4)
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    Cross polarization in reflector antennas is related to the polarization efficiency. Simple approximate expressions for the peak cross polarization are derived in terms of the polarization efficiency. Front-fed, Cassegrainian, and offset antennas are considered. It is shown that symmetrical antennas have lower peak sidelobes than offset antennas with the same polarization efficiency by approximately 2.5 dB. Excellent agreement between the present method and other methods is achieved. Formulas for the off-axis angle at which peak cross polarization takes place are also given for symmetrical and offset reflectors. It is found that for reflectors with the same D/\lambda ratio, symmetrical antennas have larger off-axis angles (1.6 times larger) for peak cross polarization in comparison with offset antennas. View full abstract»

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  • An analysis of the elliptical reflector

    Publication Year: 1979 , Page(s): 455 - 459
    Cited by:  Papers (2)
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    The distribution of the electromagnetic fields diffracted by an elliptical reflector which is fed by a line source at or near one of its two foci is studied. For the elliptic cylinder the magnitude of the fields near the foci, the size of the focal region, the displacement of the focal spot as a function of the source displacement, and the application of the method of stationary phase in calculating the fields at points distant from either focus are calculated. Explicit results are presented for the fields as a function of the eccentricity of the ellipse and the angles subtended by the reflector edges. View full abstract»

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  • Impulse response of a band-limited lossy ionospheric channel

    Publication Year: 1979 , Page(s): 548 - 551
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    Based on dispersion relation of a collisional isotropic uniform plasma, the transfer function of a lossy ionospheric channel was derived. For narrow-band signals, the transfer function can be greatly simplified, and a band-limited impulse response was obtained. It was found that when the collision frequency is only a small fraction of \omega _{0} , the center frequency of the band, an appreciable amount of energy loss is observed. By convolution the impulse response can be used to obtain the output waveform of any other input signal transmitted through the lossy medium. View full abstract»

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  • Analysis of HF pulse reflection from a randomly varying ionosphere

    Publication Year: 1979 , Page(s): 508 - 516
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (768 KB)  

    The reflection of high-frequency (HF) pulses by a randomly inhomogeneous, dispersive, and absorbing ionosphere is considered. The distortion of the transmitted pulses due to the intrinsic ionosphere dispersion, multipath effects, and frequency incoherence is related to the spatial, temporal, and frequency dependent characteristics of both the ionosphere and the troposphere. The envelope broadening of a constant-carrier pulse due to the dispersion (delay distortion) and randomness of the media (diffuse multipath) is seen to be small compared to the discrete mulfipath spread resulting from variations of the ionosphere's index of refraction with height. In the case of chirp-pulse transmission, pulse compression in the range of 20-30 dB may be achieved provided the frequency sweep of the transmitted pulse is matched to the slope of the delay of the channel and the bandwidth of the chirp pulse is large enough (0.1-10% of the center frequency). View full abstract»

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  • Large active retrodirective arrays for space applications

    Publication Year: 1979 , Page(s): 489 - 496
    Cited by:  Papers (13)  |  Patents (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    An active retrodirective array (ARA) electronically points a microwave beam back at the apparent source of an incident pilot signal. Retrodirectivity is the result of the phase conjugation of the pilot signal received by each element of the array. The problem of supplying the correct phase reference to the phase conjugation circuit (PCC) associated with each element of the array is solved by "central phasing." By eliminating the need for structural rigidity central phasing confers a decisive advantage on ARA's as large spaceborne antennas. A new form of central phasing suitable for very large arrays is described. ARA's may easily be modified to serve both as transmitting and receiving arrays simultaneously. ARA's are particularly suitable as solar power satellite antennas because they are inherently failsafe. Communication satellites and deep space probes are other suggested applications. A new kind of exact frequency-translating PCC is described. Such PCC's provide the ARA with input-output isolation and freedom from squint. The pointing errors caused by the radial and transverse components of the ARA's velocity, by the propagation medium, and by multipath are discussed. As part of a NASA funded program a two-element ARA breadboard has been built and tested at the Jet Propulsion Lab. Its performance is limited primarily by multipath-induced errors. View full abstract»

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  • Recent progress in duct propagation predictions

    Publication Year: 1979 , Page(s): 542 - 548
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (736 KB)  

    There has been a revived interest in the enhanced radio fields that are encountered in the presence of trapping or dueting atmospheric refractivity gradients either aloft or at and near the surface. Recent progress in the theoretical formulation of ducted fields is summarized, some resulting expressions for interference problems are presented, and those areas still in need of additional development are identified. View full abstract»

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  • Corrugated waveguide with helically continuous corrugations

    Publication Year: 1979 , Page(s): 564 - 567
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB)  

    The cylindrical hybrid mode propagation and radiation characteristics have been theoretically analyzed, and corresponding experimental investigations have been carried out for a corrugated waveguide with helical anisotropy. Under the influence of helical corrugation the plane of polarization of the hybrid mode is found to rotate slowly as it moves along the guide. The frequency dependence of the plane of polarization has been studied for such waveguide feeds of given length. View full abstract»

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  • On the use of pseudorandom codes for "Chirp" radar

    Publication Year: 1979 , Page(s): 480 - 485
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    The effect of transmit/receive (T/R) switching on the amibiguity function of a radar signal whose complex modulation is long compared to the minimum target delay of interest is investigated theoretically, and the theory is then applied to the specific case on an ionospheric "chirp" sounder. Various pseudorandom T/R codes are compared for their suitability for this particular radar application, and one in particular is shown to have some advantageous properties. View full abstract»

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  • Mode conversion by tunnel nonuniformities in leaky feeder communication systems

    Publication Year: 1979 , Page(s): 560 - 563
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    Using an idealized theoretical model, the inadvertent mode conversion between the bifilar and monofilar modes are dealt with in a tunnel that contains a braided coaxial cable. The tunnel is allowed to have various kinds of lateral nonuniformities such as changes of wall conductivity and permittivity. We conclude that such effects are very important in understanding leaky feeder systems. View full abstract»

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  • Design of array and line-source antennas for Taylor patterns with a null

    Publication Year: 1979 , Page(s): 474 - 479
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    An antenna pattern design technique which results in a generalized Taylor pattern, except in a narrow region where a deep null is formed, centered at a preassigned position is presented. It is shown how this technique can be applied effectively to both linear arrays and line sources. The approach is direct so that the technique does not use either iterative sampling or a perturbation procedure. It is particularly useful in the design of a large array with a prescribed deep null. Numerical results indicate that to steer such a null, adjustment of the excitation is necessary near the edges only. View full abstract»

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  • Scattering properties of satellite-borne solar cell panels

    Publication Year: 1979 , Page(s): 496 - 499
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    Scattering properties in the microwave range of solar cell panels to be used on satellites are experimentally tested both in waveguide and in free space. A grating effect, which affects free-space measurements, is discussed. The results of the study are important in the high-frequency radiation-pattern prediction for satellite antennas. View full abstract»

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Aims & Scope

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

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Editor-in-Chief                                                 Kwok W. Leung