US3886561A - Compensated zoned dielectric lens antenna - Google Patents

Compensated zoned dielectric lens antenna Download PDF

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Publication number
US3886561A
US3886561A US315693A US31569372A US3886561A US 3886561 A US3886561 A US 3886561A US 315693 A US315693 A US 315693A US 31569372 A US31569372 A US 31569372A US 3886561 A US3886561 A US 3886561A
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dielectric
eta
lens
lambda
refraction
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Expired - Lifetime
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US315693A
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John Paul Beyer
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International Telecommunications Satellite Organization
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Comsat Corp
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Priority to US315693A priority Critical patent/US3886561A/en
Priority to GB5663573A priority patent/GB1410699A/en
Priority to IT70637/73A priority patent/IT999949B/it
Priority to FR7344854A priority patent/FR2210839B1/fr
Priority to JP48139282A priority patent/JPS5918881B2/ja
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Assigned to INTERNATIONAL TELECOMMUNICATIONS SATELLITE ORGANIZATION, reassignment INTERNATIONAL TELECOMMUNICATIONS SATELLITE ORGANIZATION, ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: COMMUNICATION SATELLITE CORPORATION
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    • 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
    • H01Q15/02—Refracting or diffracting devices, e.g. lens, prism

Definitions

  • Beyer 1 COMPENSATED ZONED DIELECTRIC LENS ANTENNA [75] Inventor: John Paul Beyer, Rockville, Md.
  • Dielectric lenses have been known for some time to be suitable for focusing radio waves. Such lenses operate in a similar fashion to optical lenses. Typically a radio wave emanating from a focal point with a spherical phase front passes through a properly designed dielectric lens and exits as a radio wave with a planar phase front. This focuses the radiation into a narrow beam.
  • FIG. 1 A side view of a typical dielectric lens and the manner in which it functions is illustrated in FIG. 1.
  • the lens is a solid dielectric having an index of refraction 1 where 1 is usually greater than I.
  • the lens geometry is a hyperbola of revolution with a planar side 14.
  • a radio wave radiated from point source 12 has a spherical phase front, i.e., the locii of points of constant phase is a sphere.
  • Lines 16 represent lines of constant phase.
  • the lens effectively straightens out the phase front.
  • the lines 18 on the output side represent the lines of constant phase.
  • the number of wavelengths between any two points separated by distance, L will be (TI)(L)/ ⁇ , where n is the index of refraction of the medium.
  • the dielectric lens is shaped so that the number of wavelengths between points 12 and 26 along ray path is the same as the number of wavelengths between points 12 and 28 along ray path 22. Lenses of the type described are frequency insensitive and therefore have wide band characteristics, usually a very desirable property.
  • One of the problems with such lenses is that they are bulky and heavy relative to parabolic reflectors which would perform a similar function.
  • the desirable characteristics of such lenses include zero aperture blockage, good scanning properties, and flexible design options.
  • natural dielectric lenses having an index of refraction greater than unity have a natural, or built-in, aperture taper which is a powerful means of controlling sidelobe levels, and are inherently wide bandwidth.
  • zoning One known technique for solving both the weight and inhomogeneity problem is known as zoning. This technique, simply stated, includes removing a zone or section from the lens. Referring again to FIG. I, assume a zone 30 of width, T, and having a cylindrical shape, for example, is removed from lens 10, leaving the zone filled with free space. The width, T, is selected so that the planar phase front 18 is maintained.
  • T width, of dielectric having index of refraction 17,, and substitution of free space having index of refraction equal to I certainly changes the number of wavelengths of fequencyf between points 12 and 28 along path 22.
  • T is selected so that the change is equal to an integral number of wavelengths, the phase along line 18 will, in the area of the zone, jump by an integral multiple of 211' radians, which is equivalent to remaining constant.
  • T must satisfy the condition:
  • Equation (l) says that the phase of ray 22 at any point on the output side of lens 10 will be changed by an integral number of wavelengths, N, due to removing a width, T, of the dielectric. Further zoning can be accomplished using the same constraints. An example of multiple zones is shown in FIG. 2.
  • T is selected based on the design frequency f,,. At frequencies other than f, or integral multiples thereof, the wavelength difference caused by the removal of the zone is no longer an integral number. Consequently, the phase at point 28 will differ from that at point 26, resulting in loss of focus, deterioration of the beam, and a decrease in gain.
  • an artificial lens instead of dielectric lenses for use as the focusing means.
  • an artificial lens consists of parallel conductive slats separated by free space or other dielectric, or consists of horizontal and vertical conductive slats, forming an egg-crate arrangement, also separated by free space or other dielectric.
  • One advantage of such artificial dielectric lenses over natural dielectric lenses is that they weigh a lot less. Additionally, they typically can be made to be more homogenous than some conventional natural dielectrics which are presently used for lens antennas.
  • a problem with artificial dielectric lenses is that they are also highly frequency sensitive. Unlike natural dielectrics, the apparent index of refraction of an artificial dielectric is frequency dependent and can be expressed as:
  • zoned natural dielectric lenses and artificial dielectric lenses are frequency sensitive
  • the creation of a zone in a natural dielectric lens and the filling of that zone with an artificial dielectric results in a lens which has wider bandwidth properties than an equivalent natural dielectric lens with simple (uncompensated) zoning, weighs less than the unzoned natural dielectric lens, and is less sensitive to inhomogeneities in the dielectric.
  • the width, T, of the zone is selected so that the number of wavelengths of the design frequency through a width, T, of the artificial dielectric differs by an integral number from the number of wavelengths of the design frequency through a width, T, of the natural dielectric.
  • FIG. 1 is a cross-sectional side view of a prior art zoned natural dielectric lens.
  • FIG. 2 is a cross-sectional side view of a prior art natural dielectric lens having multiple zones.
  • FIG. 3 is a cross-sectional side view of a preferred embodiment of the present invention.
  • FIGS. 4 and 5 are, respectively, a cross-sectional side view and a perspective view of a lens constructed according to the teachings of this invention and having quarter wave matching sections.
  • FIG. 6 is a perspective view of a cylindrically shaped lens constructed in accordance with the teachings of the present invention.
  • FIG. 7 is a cross-sectional side view of an embodiment of the invention having multiple zones.
  • FIG. 3 shows a natural dielectric lens 34 having a zone 44 of cylindrical shape and a depth or width, T.
  • Point 32 represents the radiation of a radio wave
  • lines 38, 40 and 42 represent ray paths of the radio wave from point 32 through lens 34
  • line 36 represents a line of constant phase.
  • the phase from of the radiated wave which passes through the lens will be planar on the output side of lens 34. It is assumed, of course, that the lens geometry is designed in accordance with known techniques to provide a planar phase front. The number of wavelengths along edge rays 38 and 42 and center ray 40 between points 32 and line 36 will be the same. Since only the relative phase is important it can be assumed that the phase (1: at line 36 is zero for each of the rays.
  • the ray 40 will still have a phase of zero at line 36 provided the substitution of the artificial dielectric changes the number of wavelengths along path 40 by an integral number.
  • T To maintain the planar phase front, T, must satisfy the equation:
  • M is the free space wavelength of design frequency f1;
  • 1 is the apparent index of refraction of the artificial dielectric 44 at the design frequency.
  • T in accordance with equation (4) the phase front of the output wave will be maintained, provided the frequency of the wave is f If the frequency changes to f, 1],, the change in the number of wavelengths along the center ray due to the substitution of the artificial dielectric will be:
  • phase error, Adz at frequency f, given in number of wavelengths, will be the difference between D and the nearest integral number. This may be expressed as:
  • N is set at unity.
  • the zone is thus referred to as a one wavelength zone.
  • phase error at the design frequency 3.95 Gl-lz
  • the phase error at the low end of the band is;
  • phase error is,
  • Adi l 1.25 0.826/l.25 0.8)(4.2/3.95) 0.0028 wavelengths.
  • the optimum matching section has an index of refraction 1 V m 1 where 17 and 17, are the respective indices of refraction of the two interfacing mediums, and has a depth equal to 17, lt /4, where M is the free-space wavelength at the design frequency.
  • quarter wave matching sections are typically provided at both free space-lens interfaces.
  • an additional quarter wave matching section could, and prefer ably should, be provided at the interface between the natural dielectric and the artificial dielectric.
  • a lens in accordance with the present invention provided with quarter wave matching sections 50 at every interface is illustrated in FIG. 4. It should be noted that quarter wave matching sections are not necessary for the subject invention to be operable. However, such sections will improve the lens power transmission property.
  • n is the index of refraction of the natural dielectric
  • n is the apparent index of refraction of the artificial dielectric at the design frequency.
  • the index of refraction of the optimum quarter wave section at the natural-artificial interface is that of free space. Consequently, a good matching section is provided by a free space region of depth h /4.
  • FIG. 6 illustrates a cylindrical lens, constructed in accordance with the teachings of this invention.
  • the natural dielectric is shown at 60 and the artificial dielectric at 62.
  • This particular shaped lens is suitable for radiation emanating along a focal line rather than from a focal point.
  • a dielectric lens for radio wave antennas said lens being formed of a solid natural dielectric material having a zone cut-out therefrom and filled with an artificial dielectric material constructed of parallel metal conductive slats and having an apparent index of refraction n at any frequency f defined by:
  • A is the free space wavelength of frequency f
  • A is twice the slat-to-slat spacing of said artificial dielectric.
  • N is an integral number
  • A is the free space wavelength of a design frequency
  • n is the index of refraction of said natural dielectric material
  • a dielectric lens as claimed in claim 2 having stacked zones filled with said artificial dielectric material.
  • a dielectric lens for radio wave antennas said lens being formed of a solid natural dielectric material having a zone cut-out therefrom and filled with an artificial dielectric material constructed of parallel metal conductive slats and having an apparent index of refraction 11,, at any frequency f defined by:
  • A is the free space wavelength of frequency f; and h is twice the slat-to-slat spacing of said artificial dielectric; said zone having a depth T, which satisfies the equation:
  • N is an integral number
  • A is the free space wavelength of a design frequency
  • a quarter wave matching section of free space be tween the interface formed by said natural dielectric material and said artificial dielectric material.
US315693A 1972-12-15 1972-12-15 Compensated zoned dielectric lens antenna Expired - Lifetime US3886561A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US315693A US3886561A (en) 1972-12-15 1972-12-15 Compensated zoned dielectric lens antenna
GB5663573A GB1410699A (en) 1972-12-15 1973-12-06 Dielectric lens antennas
IT70637/73A IT999949B (it) 1972-12-15 1973-12-11 Antenna a lente dielettrica zonale compensata
FR7344854A FR2210839B1 (xx) 1972-12-15 1973-12-14
JP48139282A JPS5918881B2 (ja) 1972-12-15 1973-12-15 アンテナ用誘導体レンズ

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US315693A US3886561A (en) 1972-12-15 1972-12-15 Compensated zoned dielectric lens antenna

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US3886561A true US3886561A (en) 1975-05-27

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JP (1) JPS5918881B2 (xx)
FR (1) FR2210839B1 (xx)
GB (1) GB1410699A (xx)
IT (1) IT999949B (xx)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4786910A (en) * 1987-11-05 1988-11-22 American Telephone And Telegraph Company, At&T Bell Laboratories Single reflector multibeam antenna arrangement with a wide field of view
US4804970A (en) * 1985-05-06 1989-02-14 Harris Corp. Equiphase refractive antenna lens
US4872019A (en) * 1986-12-09 1989-10-03 Her Majesty The Queen In Right Of Canada As Represented By The Minister Of National Defence Radome-lens EHF antenna development
US4901086A (en) * 1987-10-02 1990-02-13 Raytheon Company Lens/polarizer radome
US5030956A (en) * 1989-04-25 1991-07-09 Murphy Quentin M Radar tomography
WO1991015879A1 (en) * 1990-04-06 1991-10-17 Microbeam Corporation Electromagnetic antenna collimator
US5227797A (en) * 1989-04-25 1993-07-13 Murphy Quentin M Radar tomography
US5652631A (en) * 1995-05-08 1997-07-29 Hughes Missile Systems Company Dual frequency radome
US5764199A (en) * 1995-08-28 1998-06-09 Datron/Transco, Inc. Low profile semi-cylindrical lens antenna on a ground plane
WO1998054788A1 (de) * 1997-05-30 1998-12-03 Robert Bosch Gmbh Antenne zum abstrahlen von hochfrequenten funksignalen
US6043784A (en) * 1997-08-27 2000-03-28 Robert Bosch Gmbh Antenna lens in particular for a motor vehicle radar system
US6075485A (en) * 1998-11-03 2000-06-13 Atlantic Aerospace Electronics Corp. Reduced weight artificial dielectric antennas and method for providing the same
US6424308B1 (en) * 2000-12-06 2002-07-23 Trw Inc. Wideband matching surface for dielectric lens and/or radomes and/or absorbers
US6624792B1 (en) 2002-05-16 2003-09-23 Titan Systems, Corporation Quad-ridged feed horn with two coplanar probes
US10971823B1 (en) * 2019-04-26 2021-04-06 Vasant Limited Artificial dielectric material and focusing lenses made of it

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1186406A (en) * 1982-05-21 1985-04-30 Her Majesty The Queen In Right Of Canada As Represented By The Minister Of National Defence Of Her Majesty's Canadian Government Dipole array lens antenna
DE112014007243A5 (de) 2014-12-11 2017-09-28 Vega Grieshaber Kg Antennenabdeckung, Verwendung einer Antennenabdeckung, Adapter zum Verbinden zweier Antennenabdeckungen und Verfahren zum Herstellen einer linsenförmigen Antennenabdeckung
FR3141126A1 (fr) 2022-10-20 2024-04-26 Psa Automobiles Sa Procédé et dispositif de limitation d’une vitesse de consigne d’un régulateur de vitesse adaptatif d’un véhicule autonome

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US2985880A (en) * 1958-04-24 1961-05-23 Edward B Mcmillan Dielectric bodies for transmission of electromagnetic waves
US3128467A (en) * 1960-02-19 1964-04-07 Don Lan Electronics Co Inc Dielectric rod radiating antenna
US3256373A (en) * 1962-07-11 1966-06-14 Robert L Horst Method of forming a cylindrical dielectric lens
US3329958A (en) * 1964-06-11 1967-07-04 Sylvania Electric Prod Artificial dielectric lens structure
US3430248A (en) * 1966-01-06 1969-02-25 Us Army Artificial dielectric material for use in microwave optics
US3465362A (en) * 1965-07-17 1969-09-02 Tokyo Keiki Kk Shell-type luneberg lens

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2978702A (en) * 1957-07-31 1961-04-04 Arf Products Antenna polarizer having two phase shifting medium
US2985880A (en) * 1958-04-24 1961-05-23 Edward B Mcmillan Dielectric bodies for transmission of electromagnetic waves
US3128467A (en) * 1960-02-19 1964-04-07 Don Lan Electronics Co Inc Dielectric rod radiating antenna
US3256373A (en) * 1962-07-11 1966-06-14 Robert L Horst Method of forming a cylindrical dielectric lens
US3329958A (en) * 1964-06-11 1967-07-04 Sylvania Electric Prod Artificial dielectric lens structure
US3465362A (en) * 1965-07-17 1969-09-02 Tokyo Keiki Kk Shell-type luneberg lens
US3430248A (en) * 1966-01-06 1969-02-25 Us Army Artificial dielectric material for use in microwave optics

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4804970A (en) * 1985-05-06 1989-02-14 Harris Corp. Equiphase refractive antenna lens
US4872019A (en) * 1986-12-09 1989-10-03 Her Majesty The Queen In Right Of Canada As Represented By The Minister Of National Defence Radome-lens EHF antenna development
US4901086A (en) * 1987-10-02 1990-02-13 Raytheon Company Lens/polarizer radome
US4786910A (en) * 1987-11-05 1988-11-22 American Telephone And Telegraph Company, At&T Bell Laboratories Single reflector multibeam antenna arrangement with a wide field of view
US5166698A (en) * 1988-01-11 1992-11-24 Innova, Inc. Electromagnetic antenna collimator
US5030956A (en) * 1989-04-25 1991-07-09 Murphy Quentin M Radar tomography
US5227797A (en) * 1989-04-25 1993-07-13 Murphy Quentin M Radar tomography
WO1991015879A1 (en) * 1990-04-06 1991-10-17 Microbeam Corporation Electromagnetic antenna collimator
US5652631A (en) * 1995-05-08 1997-07-29 Hughes Missile Systems Company Dual frequency radome
US5764199A (en) * 1995-08-28 1998-06-09 Datron/Transco, Inc. Low profile semi-cylindrical lens antenna on a ground plane
WO1998054788A1 (de) * 1997-05-30 1998-12-03 Robert Bosch Gmbh Antenne zum abstrahlen von hochfrequenten funksignalen
US6310587B1 (en) 1997-05-30 2001-10-30 Robert Bosch Gmbh Antenna for high frequency radio signal transmission
US6043784A (en) * 1997-08-27 2000-03-28 Robert Bosch Gmbh Antenna lens in particular for a motor vehicle radar system
US6075485A (en) * 1998-11-03 2000-06-13 Atlantic Aerospace Electronics Corp. Reduced weight artificial dielectric antennas and method for providing the same
US6424308B1 (en) * 2000-12-06 2002-07-23 Trw Inc. Wideband matching surface for dielectric lens and/or radomes and/or absorbers
US6624792B1 (en) 2002-05-16 2003-09-23 Titan Systems, Corporation Quad-ridged feed horn with two coplanar probes
US10971823B1 (en) * 2019-04-26 2021-04-06 Vasant Limited Artificial dielectric material and focusing lenses made of it

Also Published As

Publication number Publication date
GB1410699A (en) 1975-10-22
JPS5918881B2 (ja) 1984-05-01
JPS4985944A (xx) 1974-08-17
FR2210839A1 (xx) 1974-07-12
IT999949B (it) 1976-03-10
FR2210839B1 (xx) 1978-02-10

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