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IEE Proceedings - Microwaves, Antennas and Propagation

Issue 3 • Jun 1994

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Displaying Results 1 - 19 of 19
  • Dichroic design for the orbiting VLBI earth station antenna

    Publication Year: 1994, Page(s):181 - 184
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (220 KB)

    The design and performance of a single screen frequency selective surface (FSS) with gridded square loop patch element are described for diplexing the Xand Ku-band signals in an orbiting very long baseline interferometer (OVLBI) earth station reflector antenna system. The FSS grids were designed using an analysis code incorporating the accurate integral equation technique. The effects of the diele... View full abstract»

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  • Synthesis of vehicular antenna NVIS radiation patterns using the method of characteristic modes

    Publication Year: 1994, Page(s):151 - 154
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (236 KB)

    The method of characteristic modes is used in a novel application for the design of vehicular antennas optimised for near vertical incidence skywave (NVIS) propagation. The technique treats any structure and its associated antenna as one by computing their characteristic orthogonal functions or modes. The appropriate excitation and control of key modes allows selected radiation patterns to be synt... View full abstract»

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  • Method of partial overlapping regions for the analysis of diffraction problems

    Publication Year: 1994, Page(s):196 - 198
    Cited by:  Papers (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (192 KB)

    The technique of regularisation of the mode-matching method's equations for two-dimensional diffraction problems in waveguiding structures with complicated geometry of boundary is developed and substantiated. The approach is shown to have the clear geometry representation: a whole complex domain of field determination is subdivided into a number of overlapping regions. The method of partial overla... View full abstract»

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  • Rigorous analysis of the higher order modes, impedance and attenuation factor of coupled striplines

    Publication Year: 1994, Page(s):167 - 174
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (448 KB)

    The paper presents a rigorous and computationally efficient analysis of coupled striplines of arbitrary dimensions based on the transverse resonance diffraction (TRD) technique. The calculated higher order mode cutoff frequencies, impedance, coupling factors and attenuation factor are shown to give improved accuracy over a wide range of dimensions when compared with purely analytical and numerical... View full abstract»

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  • Fullwave analysis of multilayer microstrip lines

    Publication Year: 1994, Page(s):185 - 188
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (244 KB)

    A new fullwave analysis of microstrip line structures with multidielectric layers is presented, using a hybrid approach that combines the finite-element method and the conformal-mapping technique. Wheeler's mapping function is adopted to transform the half-infinite original domain into a finite image domain and to overcome the field singularity difficulty around the conductor edges in the original... View full abstract»

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  • EM wave scattering by a dihedral strip grating

    Publication Year: 1994, Page(s):155 - 161
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (460 KB)

    The dihedral strip grating is a thick screen which permits control over the strength of reflected and transmitted Floquet harmonics. Controllable is its frequency selectivity too. Plane-wave scattering from an infinite dihedral strip grating is formulated through an indirect mode matching technique based on Green's second theorem. The solution is successfully checked against the principles of ener... View full abstract»

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  • Multiport network analysis of frequency-selective surfaces

    Publication Year: 1994, Page(s):229 - 231
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (184 KB)

    A general multimode network describing the scattering parameters of thin conducting strip arrays is formulated and applied to frequency-selective surfaces (FSS). The transmission characteristics of a number of FSS are computed using the new model and compared with both a single mode solution and measurements. The formulation allows a substrate to be included and gives a worthwhile improvement in t... View full abstract»

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  • New stacked microstrip antenna with large bandwidth and high gain

    Publication Year: 1994, Page(s):199 - 204
    Cited by:  Papers (24)  |  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (480 KB)

    A new radiating element is presented, which can provide simultaneously a large bandwidth and high gain. It consists of four identical patches uniformly displayed within a rectangular aperture (2×2) and fed electromagnetically by a driven patch etched on a lower substrate. It is shown that a good coupling with the parasitic patches is obtained, causing a large bandwidth, and the resonance mod... View full abstract»

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  • Modified determinations of stability criteria for accurate designing the linear two-port amplifiers

    Publication Year: 1994, Page(s):238 - 240
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (200 KB)

    An important consideration in designing linear two-port amplifiers is ensuring that the amplifiers are stable. The conventional treatments are graphic methods where the input/output stability circles are first given to assure the unconditionally stable area in the Smith chart. However, it is difficult to process the input-match and output-match simultaneously, since the source and load plane are m... View full abstract»

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  • Millimetre-wave leaky-wave antennas based on slitted asymmetric ridge waveguides

    Publication Year: 1994, Page(s):175 - 180
    Cited by:  Papers (12)  |  Patents (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (324 KB)

    An analysis is presented of a class of leaky-wave antennas based on the slitted asymmetric ridge waveguide which is both easy to manufacture and very flexible in terms of electrical characteristics. The analysis is based on the development of an accurate transverse equivalent network and on the derivation of a dispersion relation which gives the complex longitudinal propagation coefficient in term... View full abstract»

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  • Graphical study of Laguerre-Gaussian beam modes

    Publication Year: 1994, Page(s):145 - 150
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (376 KB)

    Following a brief survey of the theory of Laguerre-Gaussian beam modes, expressions are derived for the paraxial vector electric and magnetic fields for wave modes of arbitrary order. The variation of field amplitude in the plane transverse to the axis of propagation is illustrated by three-dimensional graphs, and constant-amplitude contours are obtained. Also, the electric and magnetic fields in ... View full abstract»

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  • Novel differential formulation of electromagnetic scattering by dielectric cylinders of arbitrary cross-section

    Publication Year: 1994, Page(s):189 - 195
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (376 KB)

    A new differential method of electromagnetic scattering from dielectric cylinders is presented. The formulation is based on a harmonic expansion of fields in terms of cylindrical wave functions and their matching at appropriate boundaries. An infinite dimensional differential system results in for the unknown expansion coefficients. This system is projected into a finite dimensional one whose nume... View full abstract»

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  • Linear array geometry synthesis with minimum sidelobe level and null control

    Publication Year: 1994, Page(s):162 - 166
    Cited by:  Papers (12)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (276 KB)

    In the paper, a simple approach is used to design the beampattern of a nonuniform linear array with maximum mainlobe to average sidelobe ratio. The basic idea of the approach is to minimise the mean square value of the array response in certain directional regions while imposing one or several directional null constraints with respect to an error element position vector. A new estimated array geom... View full abstract»

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  • Method of lines for analysis of planar conductors with finite thickness

    Publication Year: 1994, Page(s):223 - 228
    Cited by:  Papers (8)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (324 KB)

    The semianalytical method of lines is used for the calculation of capacitances and inductances of parallel transmission lines of finite thickness. The potential function is discretised in one direction (x-co-ordinate) and the first and second derivatives are substituted with their finite difference expressions. This method does not have a convergence problem because of the singular behaviour of th... View full abstract»

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  • Rigorous analysis of lunar waveguides with the boundary element method

    Publication Year: 1994, Page(s):235 - 237
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (144 KB)

    The higher-order boundary element method is proposed to investigate the higher-order mode cutoff wavenumber in lunar waveguides and vained circular waveguides. Both TE and TM modes are considered. For symmetry, only one half of the cross-section is analysed, and electric and magnetic walls are employed. Several waveguides of different relative dimension are calculated and the results obtained are ... View full abstract»

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  • Scattered field analysis of a focused reflector using the Gabor series

    Publication Year: 1994, Page(s):216 - 222
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (436 KB)

    A Gabor series representation is used to represent the induced currents in a single reflector illuminated by a plane wave, in order to calculate the received field on the focal plane. The phase-space location property of the modulated Gaussians included in the Gabor series is used to make substantial simplifications in the determination of the scattered field. The physical optics (PO) spectral int... View full abstract»

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  • GTD fields at shadow and reflection boundaries of a polygonal cylinder

    Publication Year: 1994, Page(s):232 - 234
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (144 KB)

    The Keller diffraction coefficient is singular at the shadow and reflection boundaries. It is shown that the diffracted fields calculated by Keller's diffraction coefficients are finite at shadow and reflection boundaries of a polygonal cylinder and a slit View full abstract»

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  • Green dyadic and dipole fields for a medium with anisotropic chirality

    Publication Year: 1994, Page(s):211 - 215
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (260 KB)

    A closed-form expression is derived for the Green dyadic corresponding to a reciprocal bianisotropic medium with isotropic permittivity and permeability and arbitrary anisotropic chirality. Such a medium can be approximated, for example, by inserting in an isotropic host medium an equal number of similar right- and left-handed metal helices with suitable orientations. The solution is applied to de... View full abstract»

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  • Scattering properties of discontinuities in NRD guide

    Publication Year: 1994, Page(s):205 - 210
    Cited by:  Papers (8)  |  Patents (7)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (320 KB)

    The scattering characteristics of a guided wave by a class of discontinuities in a nonradiative dielectric (NRD) guide are systematically investigated by a method which combines the building block approach of multimode network theory with a rigorous mode-matching procedure. Some experimental data justify the effectiveness and accuracy of the present method. Extensive numerical results are obtained... View full abstract»

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