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Antennas and Propagation, IEEE Transactions on

Issue 1 • Date Jan 1990

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Displaying Results 1 - 21 of 21
  • Case study of intense scintillation events on the OTS path

    Publication Year: 1990 , Page(s): 107 - 113
    Cited by:  Papers (3)  |  Patents (100)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (476 KB)  

    Selected events of enhanced field amplitude fluctuations recorded on the Orbital Test Satellite (OTS) path have been analyzed. The statistical properties of the beacon signals together with their correlation with the concurrent radiometric signal suggest that both scintillation and a variable attenuation mechanism act to produce the field fluctuations. Analysis of the coherence between the beacon ... View full abstract»

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  • Analysis of microstrip antenna structures using the `add-on' technique

    Publication Year: 1990 , Page(s): 114 - 117
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (380 KB)  

    Microstrip antennas and antenna arrays are analyzed using the add-on technique. The goal of this work is to provide a way of handling more than 1000 unknowns while maintaining agreement with the moment method. The problem of a 1008-unknown finite array, with 11 elements and connecting and feeding lines, is an example of the capability of the method. In a CPU time of 1.5 h for each frequency point,... View full abstract»

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  • Radiation from a dipole near a general anisotropic layer

    Publication Year: 1990 , Page(s): 9 - 16
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (444 KB)  

    The radiation properties of a dipole source located near a gyrotropic layer are investigated analytically. Both electric and magnetic anisotropy of the most general form are assumed. Fourier-transform domain field representations in conjunction with matrix analysis techniques are used to facilitate the analysis. Transmission phenomena through the general anisotropic layer are investigated by exami... View full abstract»

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  • Limitations on reflector antenna gain by random surface errors, pointing errors, and the angle-of-arrival jitter

    Publication Year: 1990 , Page(s): 117 - 121
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (460 KB)  

    The effects of random surface, pointing, and angle-of-arrival errors on the antenna gain are discussed. It is shown that for manufacturing tolerance ratios greater than 105, the random surface errors decrease the antenna gain only when D/λ>3000. The pointing/angle-of-arrival error causes nonnegligible loss in gain when it exceeds approximately a few tenths of the ante... View full abstract»

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  • FDTD algorithm in curvilinear coordinates [EM scattering]

    Publication Year: 1990 , Page(s): 76 - 89
    Cited by:  Papers (79)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1048 KB)  

    The finite-difference-time-domain (FDTD) algorithm for the solution of electromagnetic scattering problems is formulated in generalized coordinates in two dimensions and implemented in a code with the lowest-order Bayliss-Turkel radiation boundary condition expressed in cylindrical coordinates. It is shown that, for a perfect conductor, such a formulation leads to a stable, well-posed algorithm an... View full abstract»

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  • Adaptive beam-space nulling of multipath signals

    Publication Year: 1990 , Page(s): 129 - 134
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (480 KB)  

    A beam-space adaptive nulling technique that has potential for applications in communication circuits degraded by multipath signals is described. The technique is based on a well-known vector relationship in beam space. A linear transformation is used to prevent the degradation of the desired signal reception. Results are presented from tests of the technique that were conducted using real multipa... View full abstract»

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  • Studies on wide inclined slots in the narrow wall of rectangular waveguide

    Publication Year: 1990 , Page(s): 24 - 29
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (408 KB)  

    Investigations of the resonant length and admittance of inclined slots in the narrow wall of a rectangular waveguide that are sufficiently wide for applications involving high power handling capacity are presented. For high accuracy, the integrals appearing in the expression for the self-reaction are evaluated numerically instead of attempting to derive closed-form expressions, which are applicabl... View full abstract»

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  • Scattering from irregular-edged planar and curved surfaces

    Publication Year: 1990 , Page(s): 137 - 141
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (364 KB)  

    An electric field integral equation (EFIE) formulation is used to describe the electromagnetic scattering from finite planar and curved perfect electrical conducting surfaces truncated by an irregular edge. The edge can have an arbitrary form if it satisfies certain differentiability requirements. Similarly, the generating curve describing the surface can be convex, concave, or a combination of bo... View full abstract»

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  • A unified approach to the design of robust narrow-band antenna array processors

    Publication Year: 1990 , Page(s): 17 - 23
    Cited by:  Papers (23)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (488 KB)  

    A unified approach to the design of robust narrowband antenna array processors is presented. The approach is based on the idea of minimizing the weighted mean-square-deviation between the desired response and the response of the processor over variations in parameters. Three specific examples of robust design are considered: robustness against directional mismatch, robustness against array geometr... View full abstract»

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  • Scattering from partial bodies of revolution

    Publication Year: 1990 , Page(s): 69 - 75
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (432 KB)  

    The electromagnetic scattering from classes of partial bodies of revolution formed by the presence of perfectly electrically or magnetically conducting (PEC or PMC) planes is investigated. It is found that when the Galerkin technique is used with a harmonic circumferential expansion, there is a modal decoupling of the integral operators. The choice of these expansions is determined by the angle su... View full abstract»

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  • Focusing properties of a microwave radiator utilizing a slotted rectangular waveguide

    Publication Year: 1990 , Page(s): 121 - 124
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (312 KB)  

    A microwave radiator, utilizing a slotted rectangular waveguide that is bent into an equiangular spiral, for focusing leaky microwaves radiated from a continuous longitudinal slot is presented. The radiation fields near the focus are derived by setting up a magnetic current on the slot. Some of the fundamental focusing properties of this spiral slotted rectangular waveguide (SSRW) radiator, such a... View full abstract»

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  • Effect of error correlations and systematic errors on average array sidelobes

    Publication Year: 1990 , Page(s): 124 - 129
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (476 KB)  

    The effect of error correlations on the average error-induced sidelobe level of a planar array is studied. It is found that correlations among the random errors rapidly decrease the average error-sidelobe level (relative to the level when all errors are uncorrelated) as the correlation radius is increased. However, even though the average error-sidelobe level decreases, there are certain types of ... View full abstract»

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  • The RCS of a rectangular microstrip patch in a substrate-superstrate geometry

    Publication Year: 1990 , Page(s): 2 - 8
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (348 KB)  

    A general scattering formula is derived for an arbitrary resonant conductive body within a layered medium, which shows that the body radar cross section (RCS) is directly related to the radiation efficiency of the body. The radar cross section of a rectangular microstrip patch antenna in a lossy substrate-superstrate configuration is then investigated as a specific case. Results are presented to s... View full abstract»

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  • Empirical-computational methods in the study of creeping waves

    Publication Year: 1990 , Page(s): 51 - 59
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (668 KB)  

    A method is described for the direct extraction of parameters characterizing the fundamental creeping wave modes by the application of elementary signal processing techniques to the total scattered radiation from arbitrary layered cylinders. Filtering is implemented by multiplying the field by suitable window functions designed to separate the creeping wave from the remaining radiation, and can be... View full abstract»

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  • On the analysis of frequency-selective surfaces using subdomain basis functions

    Publication Year: 1990 , Page(s): 40 - 50
    Cited by:  Papers (39)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (680 KB)  

    The problem of scattering from frequency-selective surfaces (FSSs) has been investigated by expanding the unknown current distribution with three different sets of basis functions, namely the roof top, surface patch, and triangular patch. The boundary condition on the total electric field on the FSS due to this current distribution is tested either by a line integral or by the Galerkin procedure. ... View full abstract»

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  • Modeling folded dipoles and feedlines for radiation and scattering

    Publication Year: 1990 , Page(s): 30 - 39
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (624 KB)  

    Dipole-like antennas, suited for use as radiating elements in large phased arrays, are modeled for efficient analysis by decomposing the antenna into a radiating mode part and a transmission line mode part. All the essential features of folded dipoles, integrated balun feedlines, and feedline scattering are contained in the models. Feedline scattering, in particular, is an important consideration ... View full abstract»

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  • The theory of chirowaveguides

    Publication Year: 1990 , Page(s): 90 - 98
    Cited by:  Papers (52)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (740 KB)  

    The theory of chirowaveguides is discussed, and their salient features are analyzed. It is shown that the Helmholtz equations for the longitudinal components of electric and magnetic fields in chirowaveguides are always coupled and that, consequently, in these waveguides individual transverse electric (TE), transverse magnetic (TM), or transverse electromagnetic (TEM) modes cannot be supported. As... View full abstract»

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  • Note on interpolational basis functions in the method of moments [EM scattering]

    Publication Year: 1990 , Page(s): 134 - 137
    Cited by:  Papers (13)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (372 KB)  

    Efficient basis sets for the method of moments may be obtained using quasi-localized bandlimited interpolational functions that, broadly speaking, are defined relative to a mean sampling rate that is adjusted to curvature and proximity to edges, thus reflecting the local spatial-frequency bandwidth. Computed scattering data in a number of structures, including perfectly conducting circular and ell... View full abstract»

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  • Identification of the natural resonance frequencies of a conducting sphere from a measured transient response

    Publication Year: 1990 , Page(s): 141 - 143
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (256 KB)  

    It is shown that the imaginary parts of the first six natural resonant frequencies of a spherical scatterer can be determined quite accurately from measurements of both its surface charge and scattered field responses. This is an important step in verifying the practicality of characterizing low-Q targets by means of their resonance frequencies. Results for the real parts of the natural f... View full abstract»

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  • Procedures for noninvasive electromagnetic property and dosimetry measurements

    Publication Year: 1990 , Page(s): 99 - 106
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (688 KB)  

    Five different formulations are presented that can be used to determine local values of the complex permittivity, electric field, polarization current density, and rate of energy deposition, within an inhomogeneous dielectric object of arbitrary shape. These formulations were obtained from the matrix equations for moment-method solutions of the electric field integral equation. Implementation of t... View full abstract»

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  • A hybrid equation approach for the solution of electromagnetic scattering problems involving two-dimensional inhomogeneous dielectric cylinders

    Publication Year: 1990 , Page(s): 60 - 68
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (752 KB)  

    A numerical procedure for the solution of electromagnetic scattering problems involving inhomogeneous dielectric cylinders of arbitrary cross section is discussed. The cases of illumination by both transverse magnetic (TM) and transverse electric (TE) plane waves are considered. The scattering problems are modeled via a hybrid integral-equation/partial-differential-equation approach. The method of... 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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Meet Our Editors

Editor-in-Chief                                                 Kwok W. Leung