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Microwaves, Antennas and Propagation, IEE Proceedings

Issue 2 • Date 2 Apr 2001

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Displaying Results 1 - 13 of 13
  • Matching characteristics of the physically short linear impedance transformer

    Publication Year: 2001 , Page(s): 137 - 139
    Cited by:  Papers (2)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (180 KB)  

    In contrast to the conventional quarter-wavelength transformer for matching two transmission lines of different characteristic impedance, it has been found that the length can be significantly shortened by using two stratified line sections in cascade. The frequency response of this short-length transformer (SLT) is investigated and it is shown that asymmetry and a reduction in matching bandwidth ... View full abstract»

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  • Modelling and pattern error correction of time domain far-field antenna measurements

    Publication Year: 2001 , Page(s): 133 - 136
    Cited by:  Papers (4)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (332 KB)  

    The paper presents a basic model for far-field antenna measurements in the time domain. Its application to range evaluation, pattern reconstruction and pattern error correction is discussed and illustrated with measurement results. The model parameters are the number of responses in the measurement and associated arrival times and amplitudes. Such parameters are solved with super-resolution techni... View full abstract»

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  • Gain enhancement of annular slot antennas

    Publication Year: 2001 , Page(s): 109 - 114
    Cited by:  Papers (3)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (408 KB)  

    The gain enhancement of an annular slot antenna fed by a cavity is studied numerically. The method of moments for bodies of revolution is used as a numerical tool for the simulations. The effect of different parameters is investigated and methods for gain enhancement are proposed. It is shown that the antenna gain can be increased by adding a dielectric layer, or conducting ring above the slots. A... View full abstract»

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  • Scattering analysis of arbitrarily shaped cylinders in a focused beam system-oblique incidence case

    Publication Year: 2001 , Page(s): 73 - 78
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (540 KB)  

    The scattering from an arbitrarily shaped cylinder for the general oblique incident case is characterised by its induced field ratio (IFR) and its co-polarised and cross-polarised scattering patterns. The paper describes how a unique focused-beam measurement system is used to determine experimentally the scattering characteristics of an arbitrarily shaped cylinder for an obliquely incident plane w... View full abstract»

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  • Resonance frequencies of annular microslots

    Publication Year: 2001 , Page(s): 125 - 128
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (280 KB)  

    Ring-shaped microslot structures have in recent years gained increasing interest as planar antenna elements. This fact, is connection with their potential use as frequency defining elements or filters in specific MIC applications, justifies the need for an efficient method to determine the resonance frequency of the dominant mode of the annular microslot as its characteristic quantity. Using a pro... View full abstract»

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  • Galerkin operators in adaptive integral method implementations

    Publication Year: 2001 , Page(s): 79 - 84
    Cited by:  Papers (9)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (368 KB)  

    The adaptive integral method (AIM) is a fast method associated with O(N1.5) or less complexity. It has been extensively used for the analysis of metallic scatterers on the basis of the electric field integral equation (EFIE), and the AIM implementation is extended to include more general surface types such as impedance, resistive, dielectric and others. The associated multipole expansio... View full abstract»

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  • Ka-band dipole holographic antennas

    Publication Year: 2001 , Page(s): 129 - 132
    Cited by:  Papers (4)  |  Patents (5)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (396 KB)  

    Dipole holographic antennas are investigated as an alternative technology to reflectors and microstrip phased arrays for use in Ka-band applications. These antennas combine the advantages of low-profile printed technology with an unconstrained feed to avoid the excessive losses associated with conventional phased array feeds. Various single-layer and two-layer designs are described. Measurements s... View full abstract»

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  • Performance analysis of dual profile corrugated circular waveguide horns for radioastronomy applications

    Publication Year: 2001 , Page(s): 119 - 122
    Cited by:  Papers (4)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (320 KB)  

    A comparative analysis of dual profile corrugated circular waveguide horns has been carried out. It comprises the radiation pattern, horn size and phase centre location and the variation over frequency. The analysis demonstrates interesting effects of the exponential section length on the horn performance, leading to optimised electrical behaviour combined with a minimum space occupation. The smal... View full abstract»

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  • Numerical analysis of a plasma waveguide with finite thickness of cladding in external magnetic field

    Publication Year: 2001 , Page(s): 115 - 118
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (292 KB)  

    The propagation characteristics of a plasma waveguide with a finite thickness of cladding immersed in an external magnetic field are presented. The effects of the collision frequency, electron cyclotron frequency, plasma thickness of cladding on propagation constants are investigated. Numerical investigations show that the attenuation of the waveguide is an oscillating function of the plasma thick... View full abstract»

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  • Analytical method for a circularly polarised rectangular microstrip antenna

    Publication Year: 2001 , Page(s): 85 - 90
    Cited by:  Papers (1)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (436 KB)  

    The paper proposes a formulation method for the wall admittance of an arbitrarily shaped microstrip antenna using spectral domain analysis. In the paper, the wall admittance of the circularly polarised rectangular microstrip antenna is calculated. The circularly polarised rectangular microstrip antenna is analysed using the cavity model. The electromagnetic fields within the antenna cavity are exp... View full abstract»

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  • Active frequency selective surfaces with ferroelectric substrates

    Publication Year: 2001 , Page(s): 103 - 108
    Cited by:  Papers (19)  |  Patents (2)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (508 KB)  

    Computed responses of two cascaded FSS, modelled with intervening dielectrics that include one or two ferroelectric layers, show that switching is possible, over -0.5 dB bandwidths of about 8%, between states of high transmission and reflection, or between high absorption and reflection of incident electromagnetic waves. In these illustrative examples, the array elements are single ring slots with... View full abstract»

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  • Full-wave characterisation of superconducting microstrip lines

    Publication Year: 2001 , Page(s): 97 - 102
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (468 KB)  

    A new theoretical model is presented to characterise a superconducting microstrip line on a lossy substrate, and the effects of strip thickness and losses on circuit performance studied. Although the high-Tc superconductor is considered anisotropic the effect of this anisotropy may be neglected in the characterisation of the microstrip transmission line. New integral equations for the e... View full abstract»

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  • Design of cross-coupled dielectric-loaded waveguide filters

    Publication Year: 2001 , Page(s): 91 - 96
    Cited by:  Papers (5)
    Save to Project icon | Click to expandAbstract | PDF file iconPDF (612 KB)  

    The dielectric loading of waveguide cavities for the design of cross-coupled filters is described. A mode-matching program has been written to compute resonant frequencies and unloaded quality factors (Q u) of the fundamental TE011 mode supported by dielectric loaded cavities. Charts are presented at 2 GHz that allow the design of a resonator with optimal Qu/volume... View full abstract»

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