WO1994000892A1 - Guide d'ondes et antenne comprenant une surface selective de frequence - Google Patents

Guide d'ondes et antenne comprenant une surface selective de frequence Download PDF

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Publication number
WO1994000892A1
WO1994000892A1 PCT/GB1992/001173 GB9201173W WO9400892A1 WO 1994000892 A1 WO1994000892 A1 WO 1994000892A1 GB 9201173 W GB9201173 W GB 9201173W WO 9400892 A1 WO9400892 A1 WO 9400892A1
Authority
WO
WIPO (PCT)
Prior art keywords
waveguide
frequency selective
array
frequency
selective surface
Prior art date
Application number
PCT/GB1992/001173
Other languages
English (en)
Inventor
John Costas Vardaxoglou
Robert Dennis Seager
Alan John Robinson
Original Assignee
Loughborough University Of Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Loughborough University Of Technology filed Critical Loughborough University Of Technology
Priority to PCT/GB1992/001173 priority Critical patent/WO1994000892A1/fr
Publication of WO1994000892A1 publication Critical patent/WO1994000892A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P3/00—Waveguides; Transmission lines of the waveguide type
    • H01P3/12—Hollow waveguides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q13/00—Waveguide horns or mouths; Slot antennas; Leaky-waveguide antennas; Equivalent structures causing radiation along the transmission path of a guided wave
    • H01Q13/02—Waveguide horns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q15/00—Devices for reflection, refraction, diffraction or polarisation of waves radiated from an antenna, e.g. quasi-optical devices
    • H01Q15/0006—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices
    • H01Q15/0013—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective
    • H01Q15/0026—Devices acting selectively as reflecting surface, as diffracting or as refracting device, e.g. frequency filtering or angular spatial filtering devices said selective devices working as frequency-selective reflecting surfaces, e.g. FSS, dichroic plates, surfaces being partly transmissive and reflective said selective devices having a stacked geometry or having multiple layers

Definitions

  • a waveguide and an antenna including a frequency selective surface are provided.
  • the present invention relates to a waveguide including a frequency selective surface and an antenna including a frequency selective surface. More specifi ⁇ cally, the invention relates to a tuneable multiband/ broadband wave guiding system and aperture antenna.
  • Waveguides and antennas for electromagnetic radia ⁇ tion are generally designed to operate at one specific frequency or within a narrow frequency band.
  • the aim of the present invention is to provide a waveguide and an antenna that have broad or multiple operating frequency bands. It is a further aim of the invention to provide a waveguide and an antenna that are tuneable to operate at different frequencies.
  • a waveguide including a frequency selective surface, the frequency selective surface being arranged to influence the frequency response of the waveguide.
  • a frequency selective surface is an array of antenna elements that acts as a passive electromagnetic filter.
  • the surface may comprise an array of electrical ⁇ ly conductive elements on a dielectric substrate or, alternatively, a plurality of apertures in a conductive surface. Electromagnetic waves incident on a surface comprising an array of conductive elements are reflected from the surface only in a narrow band of frequencies and are transmitted at other frequencies. With an array of apertures, electromagnetic waves are transmitted only in a narrow band of frequencies.
  • Such surfaces are used as multiplexers or rado es in communications systems and can operate at microwave frequencies, including mm-waves, up to infrared and optical frequencies.
  • At least one frequency selective surface may be mounted within the waveguide, to divide the waveguide longitudinally into two or more parts.
  • the frequency selective surface is parallel to a side wall thereof. Mounting a frequency selective surface within a waveguide allows the effective dimensions of the waveguide to vary with the operating frequency, thereby providing broad or multiple operating frequency bands.
  • the frequency selective surface may be provided over an open end of the waveguide.
  • the present invention further provides an antenna for microwave radiation, comprising a outer horn and an inner horn, wherein at least the inner horn includes a frequency selective surface.
  • the outer horn or horns may also comprise frequency selective surfaces.
  • the frequency selective surface may be either reconfigurable of non-reconfigurable.
  • Non-reconfigurable frequency selective surfaces are designed to operate in a particular frequency range, which is determined by the siae and the arrangement of the antenna elements and the size of the array. The operating frequency of a non- reconfigurable frequency selective surface cannot be changed .
  • a reconfigurable frequency selective surface comprises at least two arrays of elements, the arrays being arranged in close proximity with one another so that elements of a first array are closely coupled with elements of a second array adjacent to the first array.
  • the first array is displaceable with respect to the second array to adjust the frequency response of the surface.
  • the first and second arrays may be substantially parallel with one another.
  • the array elements may be conductive elements on a dielectric substrate, or apertures in a conductive substrate, or a combination of the above.
  • the first and second arrays may have a separation of no more than 0.03 wavelengths, and preferably no more than 0.003 wavelengths of the electromagnetic waves having the resonant frequency of the surface. For example, when microwaves of frequency 30GHz are to be reflected, the separation is advantageously no more than 0.225mm and preferably no more than 0.025mm.
  • the first array may be displaceable relative to the second array in a direction parallel to the surfaces of the arrays.
  • the frequency selective surface may be reconfigured by rotating the first array with respect to the second array, or by altering the distance and/or the medium separating the first array from the second array. Using that configuration, there is no limit to the distance separating the arrays.
  • the array elements may be parallel linear dipoles, and the at least one array may be displaceable in the longitudinal direction of the linear dipoles.
  • Figure 1 is a perspective view of a reconfigurable frequency selective surface
  • Figure 2 is a cross-section through the surface?
  • Figure 3 is a diagrammatic view of a part of the surface
  • Figure 4 shows the frequency response of a frequency selective surface
  • Figure 5 shows the variation of the frequency response as the surface is reconfigured
  • Figure 6 shows a waveguide including a frequency selec ⁇ tive surface
  • Figure 7 shows a prototype waveguide, used for testing its transmission response
  • Figures 8 and 9 show the transmission response of the prototype waveguide
  • Figures 9 and 10 show two forms of horn antenna employing frequency selective surfaces.
  • the waveguide 4 has a rectan- gular cross-section and includes upper and lower walls 7, 8 and two side walls 6.
  • Two frequency selective surfaces 5 are mounted parallel to its two side walls 6.
  • the frequency selective surfaces 5 divide the waveguide lon ⁇ gitudinally into two portions, an inner portion being defined by the upper and lower walls 7, 8 and the frequency selective surfaces 5, and an outer portion being defined by the upper and lower walls 7, 8 and the side walls 6.
  • the frequency selective surfaces 5 are arranged to transmit at low frequencies and to reflect at higher frequencies.
  • the surfaces 5 are then invisible to the electromagnetic waves in the lower frequency band, and the effective internal dimensions of the waveguide 4 are defined by the side walls 6 and the upper and lower walls 7, 8 of the waveguide 4.
  • the frequency selective surfaces 5 will reflect the electromagnetic waves, and the effective internal dimensions of the waveguide 4 will then be defined by the frequency selective surfaces 5 and the upper and lower walls 7, 8 of the waveguide.
  • the effective dimensions of the waveguide are therefore different for different frequencies of transmitted electromagnetic wave, so increasing the operating frequency range of the waveguide.
  • the operating frequency range of the waveguide is defined at its lower end by the cut-off frequency in the outer waveguide of the dominant TE Q propagation mode, and at its upper end by the upper limit of the band-stop range (i.e. the reflection band) of the frequency selective surface.
  • the waveguide therefore permits monomode propagation at the TE mode over a wide frequency range.
  • the reflection coefficient of the frequency selective surfaces is -1 (the ideal value)
  • the group and phase velocities of the high frequency signal in the inner waveguide and the low frequency signal in the outer waveguide will be the same. In practice, although this is approximately true at the centre of the range of operating frequencies, the phase and amplitude of the signals will deviate at other frequencies. This causes the apparent positions of the frequency selective surfaces to vary with frequency.
  • the apparent positions of the frequency selective surfaces may be made to move inwards with increasing frequency, thereby providing a non-dispersive waveguide of even greater bandwidth.
  • the operating frequency of the waveguide may be controlled electronically.
  • the frequency selec- tive surfaces which may be fixed or reconfigurable and either single or multilayer structures, can be used to provide a number of waveguide devices, such as filters, polarisers or phase shifters. The surfaces may be positioned at any location within a waveguide.
  • the reconfigurable frequency selective surfaces may be electronically tuned, the speed of the tuning and the performance of each application being governed by the array design and the process of attaining the recon- figurable frequency selective surface effect.
  • Figs. 8 and 9 show the results of experimental tests on the waveguides, which demonstrate the principles of operation of the waveguide.
  • the results were obtained using the prototype waveguide shown in Fig. 7, which consists of a standard X-band waveguide from which the narrow side walls have been removed.
  • the waveguide comprises broad upper and lower conducting walls 9, 10 having on their inner faces several longitudinal slots 11 into which frequency selective surfaces can be inserted.
  • the transmission response of the prototype in the X band (8-12.4 GHz) is shown in Fig. 8. When operated without any inserts, the prototype exhibits a moderately lossy transmission band from the cut-off frequency up to about 16GHz.
  • Fig. 9 shows the results of a similar set of measurements carried out with J-band (12.4-18 GHz) transitions attached to each end of the test prototype.
  • the separation of the frequency selective surfaces was equal to the width dimension of a standard J-band waveguide.
  • the guiding effect of the frequency selective surfaces is again displayed.
  • the design of an integrated transition incorporating frequency selective surfaces enables tuneable broadband waveguide designs to be operated with a single co-axial feed at all frequencies.
  • the null observed near to 13GHz is due to a filtering effect caused by the frequency selective surface elements and the varying positions of the electrical walls.
  • a reconfigurable frequency selective surface would enable a band-stop or a band-pass filtering response to be tuned. As shown in Fig.
  • the figure also shows the calculated reflection coefficient amplitude for a single layer large array of tripoles over the range 13 to 18 GHz.
  • the array used in the waveguide was a single line of tripole elements.
  • the reflection band of the large frequency selective surface is broadly similar to the enhanced transmission range measured in the test prototype.
  • the frequency selective surface reflection coefficients were calculated using a Floquet mode analysis, assuming that the finite line array of tripoles behaves as an infinite rectangular lattice array with vertical periodicity equal to the waveguide height.
  • Figs. 10 and 11 show a broadband pyramidal horn antenna having an outer horn 12 of conducting material and an inner horn 13, formed of fixed or reconfigurable frequency selective surfaces. The frequency selective surfaces are invisible to electromagnetic signals of low frequency, which therefore occupy the outer horn, whereas signals of higher frequency are confined within the inner horn.
  • Fig. 11 shows an alternative antenna comprising two co-axial cones 14, 15, both consisting of fixed or reconfigurable frequency selective surfaces.
  • the antenna can be tuned to a specific frequency band for improved performance and for matching to a waveguide of the type described above.
  • the walls of the outer cone 14 could be replaced by conducting walls if band tuning and/or antenna matching is not required. If desired, the antenna may include more than two cones.
  • a reconfigurable frequency selective surface consists of two parallel arrays 1, 2 of elements 3.
  • the array elements 3 may be either electri ⁇ cally conductive elements, such as dipoles, printed on a dielectric substrate, or apertures, such as slots, formed in a conductive surface (Babinet's compliment of the former).
  • a non-reconfigurable frequency selective surface consists simply of just one of the arrays 1, 2 shown in figure 1.
  • the two arrays 1,2 are arranged in close proximity with one another, so that the elements 3 of the first array 1 are closely coupled with the elements of the second array 2.
  • the separation S of the arrays is as small as possible, whilst ensuring that the elements of the first array 1 are electrically insulated from the elements of the second array 2, and will generally be of the order of 0.03 wavelengths or less, although this will depend on the particular array design, and the dielectric constant of the substrate.
  • the second array 2 is displaceable relative to the first array 1 by a small distance DS. In the embodiment shown in figure 1, the second array 2 can be displaced transversely, parallel to the surfaces of the arrays, in the direction of the Y-axis.
  • the second array 2 could be displaced in the direction of the X-axis or the Z-axis (thereby altering the distance S separating the two arrays) or it could be rotated about the Z-axis, or displaced in any combination of those directions.
  • the elements 3 of the first array 1 lie directly over the elements of the second array 2, thereby shadowing the second array 2 from the incident electromagnetic waves.
  • the frequency response of the surface is then similar to that of a single array which, as shown in figure 4, includes a narrow reflection band and upper and lower transmission bands.
  • the letters f R denote the reflection band centre frequency, which corresponds to the resonant frequency of the surface, and the letters f ⁇ denote the frequency of the lower transmission band.
  • the frequencies f R and f ⁇ of the reflection and transmission bands are determined by the length of the antenna elements 3 and the size of the array.
  • the first array 1 has a plurality of elements 3 of length LI
  • the second array 2 has a plurality of elements of length L2.
  • the second array 2 When, as shown in figure 2, the second array 2 is displaced transversely in the direction Y by a distance DS, the ends of the elements 3 of the second array 2 then extend by a small distance DL beyond the ends of the elements of the first array 1. Since the elements of the two arrays are closely coupled, this produces an increase in the overall effective length of each element, which affects the frequency response of the surface. As shown in figure 5, the reflection frequency f R of the surface is shifted by an amount that is approximately proportional to the displacement DS. The frequency response of the surface can similarly be translated by displacing the second array 2 in the X or Z directions, by rotating it about the Z-axis, or by any combination of those movements.
  • the particular frequency selective surface consists of two arrays 1,2 of linear dipoles 3, printed in a square lattice on a 0.037mm thick dielectric substrate of dielectric constant 3.
  • L represents the length of the antenna element
  • W the element's width
  • D the side length of the unit cell (equal to the separation of adjacent antenna elements).
  • L 4.3mm
  • L 3.25mm
  • the frequency response of the surface is similar to that of a single array having the dimensions and lattice arrangement of the first array 1.
  • Resonance takes place at frequencies of about 31GHz and 27GHz for normal and TE:45° states of incidence respectively.
  • the elements 3 of the second array 2 completely fill the gaps between the elements of the first array 1, and so a further increase in the displacement DS has no further effect on the frequency response of the surface.
  • each array may consist either of a plurality of conductors on a dielectric substrate, or a perforated plate, or a combination of both.
  • the antenna elements may be dipoles, cross- dipoles, tripoles, Jerusalem crosses, squares, open-ended loops or any other type of antenna element.
  • the elements need not necessarily be arranged periodically and the arrays may be planar or curved.
  • the frequency selective surface may further consist of two or more closely- coupled arrays of elements, and the respective arrays may either be displaced in a direction parallel to the surfaces of the arrays, or rotated or their separation altered, or the medium separating the arrays may be adjusted (for example, by adjusting its dielectric constant) .
  • the relative displacement of the two arrays may be controlled in various different ways.
  • piezoelectric actuators can be used to control the precise relative movement of the arrays, and the arrays can be printed directly onto the piezoelectric material.
  • the frequency selective surface may have piezoelectric actuators positioned at some sub-areas of its surface, i.e. not everywhere on its surface.
  • the arrays can be mounted at a small separation and air pumped from the gap between the arrays to alter their separation.

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  • Aerials With Secondary Devices (AREA)
  • Waveguide Aerials (AREA)

Abstract

Un guide d'ondes (4) comprend deux surfaces sélectives de fréquence (5) montées à l'intérieur du guide d'ondes parallèlement à ses parois latérales (6). Les surfaces sélectives de fréquence (5) exercent une influence sur la courbe de fréquence du guide d'ondes (4).
PCT/GB1992/001173 1992-06-29 1992-06-29 Guide d'ondes et antenne comprenant une surface selective de frequence WO1994000892A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/GB1992/001173 WO1994000892A1 (fr) 1992-06-29 1992-06-29 Guide d'ondes et antenne comprenant une surface selective de frequence

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/GB1992/001173 WO1994000892A1 (fr) 1992-06-29 1992-06-29 Guide d'ondes et antenne comprenant une surface selective de frequence

Publications (1)

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WO1994000892A1 true WO1994000892A1 (fr) 1994-01-06

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1496570A1 (fr) * 2003-07-07 2005-01-12 Harris Corporation Antenne cornet multibande comportant des surfaces à sélection de fréquence
US6906676B2 (en) 2003-11-12 2005-06-14 Harris Corporation FSS feeding network for a multi-band compact horn
US7420524B2 (en) 2003-04-11 2008-09-02 The Penn State Research Foundation Pixelized frequency selective surfaces for reconfigurable artificial magnetically conducting ground planes
EP1972882A1 (fr) 2007-03-21 2008-09-24 Dassault Aviation Fenêtre électromagnétique.
FR2914112A1 (fr) * 2007-03-20 2008-09-26 Thales Sa Guide d'onde multi-faisceaux a fentes rayonnantes
CN1945897B (zh) * 2006-10-17 2010-10-27 东南大学 基于喇叭口面频率选择表面加载的滤波天线
WO2011106005A1 (fr) * 2010-02-24 2011-09-01 Wemtec, Inc. Appareil et procédé de suppression de modes électromagnétiques dans boîtiers de micro-ondes et ondes millimétriques
EP1763102B1 (fr) * 2005-09-08 2013-02-27 SISVEL Technology Srl Unité de corrélation avec une guide d'ondes et méthode de fabrication.
US8514036B2 (en) 2007-08-14 2013-08-20 Wemtec, Inc. Apparatus and method for mode suppression in microwave and millimeterwave packages
US9000869B2 (en) 2007-08-14 2015-04-07 Wemtec, Inc. Apparatus and method for broadband electromagnetic mode suppression in microwave and millimeterwave packages
JP2015162689A (ja) * 2014-02-25 2015-09-07 日本電信電話株式会社 ホーンアンテナ装置

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB600433A (en) * 1945-10-31 1948-04-08 Henry George Booker Improvements in or relating to wireless aerials
US3028565A (en) * 1958-09-05 1962-04-03 Atomic Energy Authority Uk Microwave propagating structures
US3633206A (en) * 1967-01-30 1972-01-04 Edward Bellamy Mcmillan Lattice aperture antenna
US4028650A (en) * 1972-05-23 1977-06-07 Nippon Hoso Kyokai Microwave circuits constructed inside a waveguide
EP0468623A1 (fr) * 1990-07-24 1992-01-29 British Aerospace Public Limited Company Assemblage stratifié de surfaces sélectives en fréquence et procédé adapté de modulation des caractéristiques de puissance et fréquence
GB2253519A (en) * 1990-09-07 1992-09-09 Univ Loughborough Reconfigurable frequency selective surfaces

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB600433A (en) * 1945-10-31 1948-04-08 Henry George Booker Improvements in or relating to wireless aerials
US3028565A (en) * 1958-09-05 1962-04-03 Atomic Energy Authority Uk Microwave propagating structures
US3633206A (en) * 1967-01-30 1972-01-04 Edward Bellamy Mcmillan Lattice aperture antenna
US4028650A (en) * 1972-05-23 1977-06-07 Nippon Hoso Kyokai Microwave circuits constructed inside a waveguide
EP0468623A1 (fr) * 1990-07-24 1992-01-29 British Aerospace Public Limited Company Assemblage stratifié de surfaces sélectives en fréquence et procédé adapté de modulation des caractéristiques de puissance et fréquence
GB2253519A (en) * 1990-09-07 1992-09-09 Univ Loughborough Reconfigurable frequency selective surfaces

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 014, no. 584 (E-1018)27 December 1990 *

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7420524B2 (en) 2003-04-11 2008-09-02 The Penn State Research Foundation Pixelized frequency selective surfaces for reconfigurable artificial magnetically conducting ground planes
EP1496570A1 (fr) * 2003-07-07 2005-01-12 Harris Corporation Antenne cornet multibande comportant des surfaces à sélection de fréquence
US6985118B2 (en) 2003-07-07 2006-01-10 Harris Corporation Multi-band horn antenna using frequency selective surfaces
US6906676B2 (en) 2003-11-12 2005-06-14 Harris Corporation FSS feeding network for a multi-band compact horn
EP1763102B1 (fr) * 2005-09-08 2013-02-27 SISVEL Technology Srl Unité de corrélation avec une guide d'ondes et méthode de fabrication.
CN1945897B (zh) * 2006-10-17 2010-10-27 东南大学 基于喇叭口面频率选择表面加载的滤波天线
FR2914112A1 (fr) * 2007-03-20 2008-09-26 Thales Sa Guide d'onde multi-faisceaux a fentes rayonnantes
FR2914114A1 (fr) * 2007-03-21 2008-09-26 Dassault Avions Fenetre electromagnetique
EP1972882A1 (fr) 2007-03-21 2008-09-24 Dassault Aviation Fenêtre électromagnétique.
US8514036B2 (en) 2007-08-14 2013-08-20 Wemtec, Inc. Apparatus and method for mode suppression in microwave and millimeterwave packages
US8816798B2 (en) 2007-08-14 2014-08-26 Wemtec, Inc. Apparatus and method for electromagnetic mode suppression in microwave and millimeterwave packages
US9000869B2 (en) 2007-08-14 2015-04-07 Wemtec, Inc. Apparatus and method for broadband electromagnetic mode suppression in microwave and millimeterwave packages
US9362601B2 (en) 2007-08-14 2016-06-07 Wemtec, Inc. Apparatus and method for broadband electromagnetic mode suppression in microwave and millimeterwave packages
WO2011106005A1 (fr) * 2010-02-24 2011-09-01 Wemtec, Inc. Appareil et procédé de suppression de modes électromagnétiques dans boîtiers de micro-ondes et ondes millimétriques
JP2015162689A (ja) * 2014-02-25 2015-09-07 日本電信電話株式会社 ホーンアンテナ装置

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