Directivity and Beamwidth Approximations for Large Scanning Dolph-Chebyshev Arrays

Directivity and Beamwidth Approximations for Large Scanning Dolph-Chebyshev Arrays PDF Author: Charles J. Drane (Jr.)
Publisher:
ISBN:
Category : Antenna radiation patterns
Languages : en
Pages : 38

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Book Description
Directivity and beamwidth for radiation patterns corresponding to the optimum Dolph-Chebyshev design have heretofore been determined by means of formulas that, although exact, are intractable to computation and not particularly open to physical interpretation. Approximate but accurate formulas are presented here in closed form, for the purpose of easy examination and computation of directivity and beamwidth for large scannable Dolph-Chebyshev arrays. Array length, number of array elements, the spacing of these elements, and the sidelobe level desired are parameters in this study. The maximum achievable directivity for Chebyshev arrays is in principle limited, regardless of how large the array becomes. Data is given to establish the array length required to obtain a value of directivity at some prescribed level below the maximum value. Comparisons between exact and approximate theory are presented in graphical form in such a way as to illustrate the lower limits of array size for which the approximations are valid. Element spacings less than a half-wavelength are included in this study. (Author).

Directivity and Beamwidth Approximations for Large Scanning Dolph-Chebyshev Arrays

Directivity and Beamwidth Approximations for Large Scanning Dolph-Chebyshev Arrays PDF Author: Charles J. Drane (Jr.)
Publisher:
ISBN:
Category : Antenna radiation patterns
Languages : en
Pages : 38

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Book Description
Directivity and beamwidth for radiation patterns corresponding to the optimum Dolph-Chebyshev design have heretofore been determined by means of formulas that, although exact, are intractable to computation and not particularly open to physical interpretation. Approximate but accurate formulas are presented here in closed form, for the purpose of easy examination and computation of directivity and beamwidth for large scannable Dolph-Chebyshev arrays. Array length, number of array elements, the spacing of these elements, and the sidelobe level desired are parameters in this study. The maximum achievable directivity for Chebyshev arrays is in principle limited, regardless of how large the array becomes. Data is given to establish the array length required to obtain a value of directivity at some prescribed level below the maximum value. Comparisons between exact and approximate theory are presented in graphical form in such a way as to illustrate the lower limits of array size for which the approximations are valid. Element spacings less than a half-wavelength are included in this study. (Author).

Technical Abstract Bulletin

Technical Abstract Bulletin PDF Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 780

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Scientific and Technical Aerospace Reports

Scientific and Technical Aerospace Reports PDF Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 388

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Antenna Handbook

Antenna Handbook PDF Author: Y.T. Lo
Publisher: Springer Science & Business Media
ISBN: 146156459X
Category : Technology & Engineering
Languages : en
Pages : 2282

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Book Description
Techniques based on the method of modal expansions, the Rayleigh-Stevenson expansion in inverse powers of the wavelength, and also the method of moments solution of integral equations are essentially restricted to the analysis of electromagnetic radiating structures which are small in terms of the wavelength. It therefore becomes necessary to employ approximations based on "high-frequency techniques" for performing an efficient analysis of electromagnetic radiating systems that are large in terms of the wavelength. One of the most versatile and useful high-frequency techniques is the geometrical theory of diffraction (GTD), which was developed around 1951 by J. B. Keller [1,2,3]. A class of diffracted rays are introduced systematically in the GTD via a generalization of the concepts of classical geometrical optics (GO). According to the GTD these diffracted rays exist in addition to the usual incident, reflected, and transmitted rays of GO. The diffracted rays in the GTD originate from certain "localized" regions on the surface of a radiating structure, such as at discontinuities in the geometrical and electrical properties of a surface, and at points of grazing incidence on a smooth convex surface as illustrated in Fig. 1. In particular, the diffracted rays can enter into the GO shadow as well as the lit regions. Consequently, the diffracted rays entirely account for the fields in the shadow region where the GO rays cannot exist.

The Nonlinear Interaction of a Radio-frequency Wave with an Inhomogeneous Plasma Slab

The Nonlinear Interaction of a Radio-frequency Wave with an Inhomogeneous Plasma Slab PDF Author: Robert J. Papa
Publisher:
ISBN:
Category : Electromagnetic waves
Languages : en
Pages : 18

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Characteristic Wave Cataloguing for Ray Path Determination

Characteristic Wave Cataloguing for Ray Path Determination PDF Author: YĆ«ji Inoue
Publisher:
ISBN:
Category : Geomagnetism
Languages : en
Pages : 38

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Book Description
Wave cataloguing suitable for ray tracing of a pulsed wave packet in a weakly-dissipative, horizontallystratified magnetoionic medium is described, Particular attention is devoted to the cataloguing of the various characteristic waves so that the influence of the local ionization density and collision frequency can be understood. The procedure presented is applicable under general incident conditions and complex refractive index surfaces. The Booker quartic equation is used to derive the unambiguous wave normals and wave identification is obtained from the dispersion equation. A modified CMA. diagram including collisions is illustrated. (Author).

The Control of Electromagnetic Scattering by Impedance Loading

The Control of Electromagnetic Scattering by Impedance Loading PDF Author: J. K. Schindler
Publisher:
ISBN:
Category : Electromagnetism
Languages : en
Pages : 24

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Satellite Observations of Low-energy Primary Cosmic Ray Nuclei of Charges Z [greater Than Or Equal To] 6

Satellite Observations of Low-energy Primary Cosmic Ray Nuclei of Charges Z [greater Than Or Equal To] 6 PDF Author: Y. K. Lim
Publisher:
ISBN:
Category : Artificial satellites
Languages : en
Pages : 14

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Microwave Measurements of Partially Coherent Fields

Microwave Measurements of Partially Coherent Fields PDF Author: J. L. Poirier
Publisher:
ISBN:
Category : Chickens
Languages : en
Pages : 20

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The Application of a System of Fixed-rotating Vectors to Circuit Analysis and Synthesis

The Application of a System of Fixed-rotating Vectors to Circuit Analysis and Synthesis PDF Author: Carl T. Case
Publisher:
ISBN:
Category : Dielectrics
Languages : en
Pages : 22

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Book Description
A system of fixed-rotating vectors can be used to study the impedance loci of functions of the first Foster form and of systems including negative impedance converters. Of particular interest in the field of dielectrics and biological membrane studies is a parallel RC network, where the dielectric of the capacitor is given by the Debye dispersion relations. Such a network also falls into the category of the first Foster form.