By Topic

Antennas and Propagation, IEEE Transactions on

Issue 3 • Date May 1970

Filter Results

Displaying Results 1 - 25 of 37
  • [Front cover and table of contents]

    Publication Year: 1970 , Page(s): 0
    Save to Project icon | Request Permissions | PDF file iconPDF (276 KB)  
    Freely Available from IEEE
  • The John T. Bolljahn memorial award

    Publication Year: 1970 , Page(s): 308
    Save to Project icon | Request Permissions | PDF file iconPDF (69 KB)  
    Freely Available from IEEE
  • Forty years ago: Maxwell's theory invades engineering - and grows with it

    Publication Year: 1970 , Page(s): 309 - 322
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1619 KB)  

    A story of my personal involvement in a rapid evolution of high-frequency electrical communication that began forty years ago and led to the merger of Kelvin's transmission-line theory, which had been the cornerstone of the telephone engineer's thinking, and more inclusive Maxwell's field theory is described. The early sections of this paper describe the state of electrical theories in those days, the environment in which I found myself, my prveious interests and education, and the problems I was presented with; these are the four factors which determined the direction of my subsequent work. In the course of this work I found that, contrary to the then prevailing belief, Kelvin's transmission-line equations were consistent with Maxwell's field theory and the restrictive assumptions usually made in derivations of these equations are sufficient but not necessary. The major part of this paper presents a sketch of the gradual development of comprehensive wave-propagation equations which are applicable to a wide variety of guiding structures. These equations form also the basis of a comprehensive antenna theory. The concluding section describes briefly my mathematical theory of linear arrays which led to the discovery of superdirective arrays. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Correction to "Scattering from crossed wires"

    Publication Year: 1970 , Page(s): 392
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (87 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radiation from TE10mode slots on circular and elliptical cylinders

    Publication Year: 1970 , Page(s): 400 - 403
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (519 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Table of the field patterns of a loaded resonant circular loop

    Publication Year: 1970 , Page(s): 416 - 418
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB)  

    A table of E - and H -plane patterns of the circular loop antenna with \beta b = 1.0 loaded with Z_{L} = R + jX at \phi = 180\deg is presented. The table gives useful information for determining the values of the load impedance for a given field pattern. The results were experimentally examined. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Experimental resolution of surface-wave antenna radiation into feed and terminal patterns

    Publication Year: 1970 , Page(s): 420 - 422
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (288 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Empirical formulas for E-plane creeping waves on general smooth conducting bodies

    Publication Year: 1970 , Page(s): 432 - 434
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (270 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • [Back cover]

    Publication Year: 1970 , Page(s): c4
    Save to Project icon | Request Permissions | PDF file iconPDF (375 KB)  
    Freely Available from IEEE
  • On the design and performance of feeds for correcting spherical aberration

    Publication Year: 1970 , Page(s): 343 - 351
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (928 KB)  

    The maximum power that can be received from the currents in a spherical reflector is obtained with that feed which, when transmitting, produces a tangential electric field, at the surface of a mathematical cylinder that just encloses it, equal to the conjugate of the field that would be produced by the reflector currents if there were a theoretically perfect absorber on the axis. This optimum tangential field is worked out in the form E_{0} +(\lambda /R)^{1/2}E_{1}+O(\lambda /R) , R being the radius of the reflector and \lambda the wavelength. The results produced by typical feeds designed according to this prescription have been computed for arrays of dipoles spaced along the axis. Typical aperture efficiencies for the Arecibo dish are 90 percent at 100 MHz and within 1 percent of the optical limit at 600 MHz. The optical limit is not 100 percent, however, because of polarization mismatch. More than 98 percent of the power is concentrated onto the dish abbve 300 MHz. Results are available for 30 to 3000 MHz, 0 to 60\deg scan angle, and various dipole arrangements. Waveguide and dipole feeds for receiving arbitrary polarization, and measurement techniques for designing and testing them, are described. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A simple approximation to the current on the surface of an isolated thin cylindrical center-fed dipole antenna of arbitrary length

    Publication Year: 1970 , Page(s): 399 - 400
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    The use of a simple trigonometric series to approximate the current distribution on isolated center-fed dipole antennas has been found to give accurate results. Unilike iterative and numerical solutions, the functional form of the approximate distribution permits the simple computation of the axial electric fields and radiating properties of the dipole. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of finite parallel-plate waveguide arrays

    Publication Year: 1970 , Page(s): 328 - 334
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (656 KB)  

    An analysis has been carried out to determine the edge effects in finite parallel-plate waveguide arrays. The method used in the evaluation is to compare the element patterns and reflection coefficients versus scan for finite arrays with the corresponding results for hypothetical infinite arrays. It is found that, in arrays of empty waveguides, an element has to be about four or five elements removed from the edge in order to be regarded as being in an infinite array environment. On the other hand, when the waveguides are loaded with dielectric plugs having suitable combination of parameters, considerably more elements are needed for the simulation of an infinite array environment due to the appearance of the resonant null in the array transmission coefficient. It is found, moreover, that even though there may be substantial variation in the radiation properties from element to element in finite arrays, particularly so in the case of moderately sized arrays, this variation does not seem to severely degrade the array performance in terms of beamwidth and sidelobe levels. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Matching focal-region fields with hybrid modes

    Publication Year: 1970 , Page(s): 404 - 405
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (224 KB)  

    A previous anlysis of circularly symmetric reflectors has shown that the focal-region fields consist of an infinite spectrum of hybrid waves. This communication shows that these fields in the case of paraboloidal and spherical reflectors can be closely matched over the open end of a corrugated waveguide propagating a small number of hybrid modes. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Waveguide antennas illuminating a metal sheet

    Publication Year: 1970 , Page(s): 396 - 399
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Experimental measurements of the admittance of rectangular or circular waveguide-fed apertures illuminating a displaced conducting plate of finite area are compared with calculations where the antenna ground plane and displaced conducting boundary are infinite in extent. Also, included are results where dielectric plugs are placed in the aperture. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Theory of coupled monopoles

    Publication Year: 1970 , Page(s): 360 - 366
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    Accurate numerical values of mutual and self-admittances are obtained for an array consisting of two monopoles having different lengths and radii. The monopoles are actually protrusions of the inner conductors of coaxial cables. The sheaths of the cables are connected to a perfectly conducting ground screen. Restrictions in the theory are the following: the monopoles must be thin, a/\lambda \ll 1 where a is the radius and \lambda the wavelength, b < 3a where b is the radius of the coaxial cable sheath, and d > 10a where d is the separation of the monopoles. The procedure employed to obtain the mutual and self-admittances is to derive simultaneous integral equations for the current distributions and to solve the integral equations numerically. The results are given for the most part in graphical form. Comparisons are made with existing theory and with experimental data. Excellent agreement in all cases is observed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Phase measurements with an interferometer baseline of 11.3 km

    Publication Year: 1970 , Page(s): 375 - 379
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Observations with a phase-stable radio-link interferometer are described. Measurements of phase stability have been made at 2595 MHz with a baseline of 11.3 km. The phase behavior is worse in summer than in winter and this is attributed to changes in the atmospheric water content. Phase fluctuations are not large enough to affect seriously aperture-synthesis measurements. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radiation from sources in the presence of a flat earth

    Publication Year: 1970 , Page(s): 423 - 424
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    The authors call attention to the equivalence between Sommerfeld's formulation for an oscillating dipole and the result based on the dyadic Green function technique. The complication resulting from the use of the set of the longitudinal vector wave functions in formulating electromagnetic problems is also pointed out View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analytical, numerical, and experimental investigation of guided waves on a periodically strip-loaded dielectric slab

    Publication Year: 1970 , Page(s): 379 - 388
    Cited by:  Papers (27)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB)  

    The electromagnetic waves guided by a periodically strip-loaded dielectric slab were investigated. The determinantal equation was obtained by assuming that the strips are narrow as compared to all other linear dimensions. Numerical results involving different combinations of the linear and dielectric parameters are presented in terms of k-\beta diagrams. The amplitudes of the space harmonics were computed and are discussed in connection with the characteristic phenomena such as radiation and coupling. In particular, the relations between the attenuation of the guided waves and the space-harmonic amplitudes are pointed out. As an interesting phenomenon, real solutions have been found to occur in the complex-wave region and this new result has been explained in the light of the space-harmonic amplitudes. The numerical results in the backward-radiation region have been verified experimentally by two different methods: by measuring the phase and amplitude variation in the near field and by calculation from radiation patterns. In both cases, good agreement with the theoretical results has been obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radar and DC pulse signatures

    Publication Year: 1970 , Page(s): 430 - 431
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB)  

    Radar and dc pulses of Gaussian shape are reflected from dry, damp, and wet earth for both vertical and horizontal polarization. The envelope of the radar pulse is retrieved following reflection and examined for distortion. The shape of the reflected dc pulse is also determined. Pulse distortion resulting from multiple reflections is easily formulated by constructing a composite transfer function consisting of the product of reflection coefficients and retardation factors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Antenna processing for surface target detection

    Publication Year: 1970 , Page(s): 335 - 342
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    An antenna processing system for target detection in receiver noise and heavy clutter is formulated by means of spacetime decision theory. The theory is applied to the case of a single target in clutter, with unknown target location and unknown amplitude and phase of the target return. The clutter background is assumed to be uniform in average power over the field of view. The target detection is accomplished by means of a generalized likelihood ratio test. A block diagram of the resulting decision-theoretic antenna processing system is shown. The decision-theoretic array does not form a beam in the ordinary sense, and consequently has equal gain in all directions in the forward hemisphere. However, the usual loss in gain occurring in conventional antennas which are omnidirectional does not occur in the decision-theoretic array. The decision-theoretic array is compared with conventional arrays to show the improvement possible by using the former. The quality criterion used to compare the systems is average risk, or the average probability of error in decision making. The array requires no scanning of any sort and is fixed relative to the vehicle that carries it. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A bound on the multiple scattered power from a plasma medium

    Publication Year: 1970 , Page(s): 438 - 439
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    A measure of the validity of the first Born approximation for scattering from an inhomogeneous plasma is obtained. This measure is derived using the inequalities appropriate to quadratically summable functions and bounded operators. A simple upper bound for the ratio of multiple scattered power to first Born power is derived as a function of B , the sufficiency condition for the convergence of the series. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An integral for obtaining exactly the electromagnetic field transmitted through a plasma slab having specified electron density-collision frequency profiles

    Publication Year: 1970 , Page(s): 434 - 435
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    The reflection coefficient of a nonhomogeneous plasma slab satisfies the Riccati differential equation. When the differential equation for the transmission coefficient is combined with the Riccati equation, the resulting expression is analytically integrable. It is demonstrated that transmission of an electromagnetic field through the slab may be expressed entirely in terms of an integral involving the complex wavenumber and reflection coefficient of the medium. It is shown that the exact theory presented here yields correct results when used to obtain the transfer function for a homogeneous imperfectly conducting sheet. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Illumination efficiency of a shaped Cassegrain system

    Publication Year: 1970 , Page(s): 411 - 412
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    Using geometrical optics approximation, an expression is derived for the illumination efficiency of a shaped Cassegrain system when the feed pattern differs from a given pattern used for designing the shaped reflector system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • UHF antenna gain calibration

    Publication Year: 1970 , Page(s): 406 - 407
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (184 KB)  

    Theoretical and experimental results have shown that a satellite repeater can be used to measure accurately transmit and receive gains of ground-communications antennas. The satellite provides a uniform phase front and, for any appreciable elevation angle, meets the height requirement as a boresight source for large-aperture antennas. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Backfire antennas with dipole elements

    Publication Year: 1970 , Page(s): 367 - 374
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (808 KB)  

    A method is set up for a theoretical investigation of arbitrary backfire antennas based upon dipole structures. The mutual impedance between the dipole elements of the antenna is taken into account, and the field radiated due to a surface wave reflector of finite extent is determined by calculating the surface current distribution on the reflector plate. Numerical results obtained for Yagi backfire antennas and short-backfire antennas using this theory are compared with experimental results. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

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

Full Aims & Scope

Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung