US3860927A - Dielectric reflector for electric waves - Google Patents

Dielectric reflector for electric waves Download PDF

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Publication number
US3860927A
US3860927A US378376A US37837673A US3860927A US 3860927 A US3860927 A US 3860927A US 378376 A US378376 A US 378376A US 37837673 A US37837673 A US 37837673A US 3860927 A US3860927 A US 3860927A
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United States
Prior art keywords
reflector
spherical
dielectric lens
electric wave
lens
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Expired - Lifetime
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US378376A
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English (en)
Inventor
Hiroshi Ota
Kazumi Mizutani
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Tokyo Keiki Inc
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Tokyo Keiki Co Ltd
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Publication date
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Publication of US3860927A publication Critical patent/US3860927A/en
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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
    • H01Q15/23—Combinations of reflecting surfaces with refracting or diffracting devices

Definitions

  • ABSTRACT A weatherproof dielectric reflector for electric waves having a spherical dielectric lens, an annular electric wave reflector of predetermined width disposed on the spherical surface of the spherical dielectric lens at a position about a horizontal plane passing the central point of the spherical dielectric lens or a point vertically spaced apart from the central point of the spherical dielectric lens, a dish-shaped electric wave reflector of predetermined area disposed on the spherical surface of the spherical dielectric lens at a position about a vertical line passing the central point of the spherical dielectric lens and extending downwardly thereof, a covering for the reflectors and lens, and a support therefor.
  • This invention relates to a dielectric reflector for electric waves employing a spherical dielectric lens, and more particularly to a dielectric reflector for electric waves adapted for use with, for example, a lifesaving outfit to ensure that, in the case of a disaster at sea, accurate positions of survivors using the life-saving outfit can readily be found by radar on search ships and search planes.
  • this invention is to provide a novel dielectric reflector for electric waves which can be used with a life-saving outfit and facilitates finding accurate positions of survivors at sea by radar on search ships and search planes.
  • the weatherproof dielectric reflector has sufficiently large reflection factor and radar cross section and exhibits omnidirectional characteristics in a horizontal plane and upward reflection characteristic. Consequently, the use of the dielectric reflector with the life-saving outfit ensures to facilitate a search for survivors by search ships and planes equipped with radar.
  • FIGS. 1 and 2 are schematic front views illustrating examples of a dielectric reflector of this invention.
  • FIG. 1 illustrates one example of the dielectric reflector for electric waves according to this invention, which comprises a spherical dielectric lens 1 of known Luneberg lens construction, an annular electric wave reflector 2 wrapped around it and a dish-shaped electric wave reflector 3 mounted on the lens 1.
  • the annular electric wave reflector 2 is disposed on the spherical surface of the dielectric lens 1 at a position about a horizontal plane passing the central point of the lens 1 and has a width in a vertical direction expressed by a predetermined central angle 0 to the central point 0.
  • the dish-shaped electric wave reflector 3 is mounted on the spherical surface of the lens 1 at a position about a vertical line passing the central point 0 and extending downwardly thereof and has an area expressed by a predetermined central cubic angle (1) to the central point 0.
  • the electric wave reflectors 2 and 3 may be made of a conductive plate material or a conductive foil material. It is preferred to cover both of the electric reflectors 2 and 3 with a thin protective film 4 of an electric wave transparent material as indicated by a chain line in the figure. Further, it is preferred to provide a support 5 by appropriate means at a position, for example, corresponding to the electric wave reflector 3 for the attachment of the dielectric reflector to a life preserver, for example, a life boat.
  • radar waves which arrive at the dielectric reflector along a horizontal plane, in the figure, from the left-hand side, as indicated by the arrow A, enter the dielectric lens I at a position, not covered by the electric wave reflector 2, and are focused by the lens I to a point on its right-hand surface in the figure.
  • the radar wave thus focused is reflected at the position of the reflector 2 back to the left in the figure and out from the lens 1.
  • a re flected radar wave is obtained based on the horizontal incident radar wave.
  • the annular electric wave reflector 2 is wrapped around the dielectric lens 1 at a position about a horizontal plane passing the central point 0, even if radar waves enter the dielectric lens 1 in any direction in a horizontal plane, the reflected radar wave can be obtained from the dielectric reflector. Therefore, the dielectric reflector has omnidirectional reflection characteristics in a horizontal plane. Further, radar waves striking the dielectric reflector from above as indicated by the arrow B is similarly focused in the lens 1 to a point on its lower surface and reflected back upwardly by the electric wave reflector 3.
  • the dielectric reflector of this invention has omnidirectional reflection characteristics in a horizontal plane and upward reflection characteristic.
  • the dielectric reflector employs the dielectric lens, and hence has large reflection factor and radar cross section. Consequently, the provision of the dielectric reflector of this invention in the life-saving outfit for a disaster at sea ensures to facilitate a search by search ships or planes equipped with radar. This is especially true in the case where the dielectric lens 1 is of the Luneberg lens construction as described above.
  • the dielectric lens I can be made of a dielectric material of relatively small specific density such as polystyrene or the like, the dielectric reflector of this invention is light as a whole. Accordingly, when the dielectric reflector is assembled with the life-saving outfit, it is not necessary to take its buoyancy into consideration.
  • the electric wave reflector 2 has been described to be disposed on the dielectric lens 1 at the position about the horizontal plane passing the central point 0 but the dielectric reflector may be of such a construction as depicted in FIG. 2 which is identical with that of FIG. 1 except that the electric wave reflector 2 is disposed at a position about a horizontal plane passing a point 0' a little apart from the central point 0 in a vertical direction.
  • the dielectric reflector is slightly tilted as a while, it provides the same effects as those obtainable with the reflector of FIG. 1.
  • the invention has been described in connection with the case where the dielectric lens has the Luneberg lens construction (the dielectric constant varies in its radial direction), the invention is also applicable to the case where the dielectric lens is of the type having a constant dielectric constant in the radial direction.
  • a dielectric reflector for electric waves for use with a life-saving outfit comprising a spherical dielectric lens, an annular electric wave reflector having a predetermined width and disposed on the spherical surface of the spherical dielectric lens at a position about a horizontal plane passing the central point of the spherical dielectric lens, a dish-shaped electric wave reflector having a predetermined area and disposed on the spherical surface of the spherical dielectric lens at a position about a vertical line passing through the central point of the spherical dielectric lens and extending downwardly thereof, a protective film of an electric wave transparent material covering the spherical dielectric lens together with the annular electric wave reflector and the dish-shaped electric wave reflector, and a support extending downwardly from the position of the dish-shaped electric wave reflector.
  • a dielectric reflector for electric waves for use with a life-saving outfit comprising a spherical dielectric lens, an annular electric wave reflector having a predetermined width and disposed on the spherical surface of the spherical dielectric lens at a position about a horizontal plane passing a point vertically spaced apart from the central point of the spherical dielectric lens, a dish-shaped electric wave reflector having a predetermined area and disposed on the spherical surface of the spherical dielectric lens at a position about a vertical line passing through the central point of the spherical dielectric lens and extending downwardly thereof, a protective film of an electric wave transparent material covering the spherical dielectric lens together with the annular electric wave reflector and the dish-shaped electric wave reflector, and a support extending downwardly from the position of the dish-shaped electric wave reflector.

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US378376A 1972-07-13 1973-07-11 Dielectric reflector for electric waves Expired - Lifetime US3860927A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP47070463A JPS5237906B2 (da) 1972-07-13 1972-07-13

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US3860927A true US3860927A (en) 1975-01-14

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JP (1) JPS5237906B2 (da)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938151A (en) * 1970-08-14 1976-02-10 The United States Of America As Represented By The Secretary Of The Navy Passive radar decoy having a large cross section
US5430444A (en) * 1991-08-21 1995-07-04 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Radar reflectors
US20090302239A1 (en) * 2004-08-19 2009-12-10 Lenstar Co., Ltd. Device using dielectric lens

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS514308B1 (da) * 1970-06-25 1976-02-10
JPS5232481A (en) * 1975-09-05 1977-03-11 British United Shoe Machinery Method and apparatus for making information support medium for automatic control machine control
JPS598841B2 (ja) * 1978-10-05 1984-02-28 大阪機工株式会社 金型加工用ｎｃデ−タ作成方法
JPS598842B2 (ja) * 1978-10-05 1984-02-28 大阪機工株式会社 倣い用モデルを利用した金型加工自動化方法
JPS598843B2 (ja) * 1978-10-05 1984-02-28 大阪機工株式会社 金型荒加工用ｎｃデ−タ作成方法
EP0212963A3 (en) * 1985-08-20 1988-08-10 Stc Plc Omni-directional antenna

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2455469A (en) * 1945-10-11 1948-12-07 Pak Parachute Company Ltd Meteorological balloon
US2580921A (en) * 1947-10-01 1952-01-01 Rca Corp Radio reflector
US2814038A (en) * 1953-07-29 1957-11-19 Westinghouse Electric Corp Lightweight antennas
US3206749A (en) * 1961-03-20 1965-09-14 Ryan Aeronautical Co Spherical checkerboard reflector
US3307187A (en) * 1966-03-11 1967-02-28 Armstrong Cork Co Omniazimuthal reflectors
US3334345A (en) * 1965-06-02 1967-08-01 Micronetics Inc Passive radar target augmentor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2455469A (en) * 1945-10-11 1948-12-07 Pak Parachute Company Ltd Meteorological balloon
US2580921A (en) * 1947-10-01 1952-01-01 Rca Corp Radio reflector
US2814038A (en) * 1953-07-29 1957-11-19 Westinghouse Electric Corp Lightweight antennas
US3206749A (en) * 1961-03-20 1965-09-14 Ryan Aeronautical Co Spherical checkerboard reflector
US3334345A (en) * 1965-06-02 1967-08-01 Micronetics Inc Passive radar target augmentor
US3307187A (en) * 1966-03-11 1967-02-28 Armstrong Cork Co Omniazimuthal reflectors

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3938151A (en) * 1970-08-14 1976-02-10 The United States Of America As Represented By The Secretary Of The Navy Passive radar decoy having a large cross section
US5430444A (en) * 1991-08-21 1995-07-04 The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland Radar reflectors
US20090302239A1 (en) * 2004-08-19 2009-12-10 Lenstar Co., Ltd. Device using dielectric lens
US8471757B2 (en) * 2004-08-19 2013-06-25 Electronic Navigation Research Institute, An Independent Administrative Institution Device using dielectric lens

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Publication number Publication date
JPS5237906B2 (da) 1977-09-26
JPS4929555A (da) 1974-03-16

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