US2640154A - Achromatic lens antenna - Google Patents

Achromatic lens antenna Download PDF

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Publication number
US2640154A
US2640154A US134788A US13478849A US2640154A US 2640154 A US2640154 A US 2640154A US 134788 A US134788 A US 134788A US 13478849 A US13478849 A US 13478849A US 2640154 A US2640154 A US 2640154A
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US
United States
Prior art keywords
lens
electromagnetic wave
section
compound
stepped
Prior art date
Legal status (The legal status 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 status listed.)
Expired - Lifetime
Application number
US134788A
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English (en)
Inventor
Winston E Kock
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AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
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
Priority to BE500060D priority Critical patent/BE500060A/xx
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US134788A priority patent/US2640154A/en
Priority to FR1028356D priority patent/FR1028356A/fr
Priority to CH296201D priority patent/CH296201A/de
Priority to DEW4775A priority patent/DE838777C/de
Application granted granted Critical
Publication of US2640154A publication Critical patent/US2640154A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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

  • This invention relates to electromagnetic wave lenses and more particularly to a wide frequency band metallic microwave lens.
  • a six-zone unstepped metalliclens having am'aximum thickness of twelve wavelengths has a band of approximately 3 per cent. Stepping-the zones increases the band width to approximately '7 per cent, the increase being only *4 percent. In structures proportioned in accordance with the principles of the present invention, the band width is increased to a value in the order of per cent. In accordance :with the established practice .of those skillediin theart, the frequency band width of a device is expressed as the percentage obtained by dividing the width of "the handover which a given device per-iorms satisfactorily in cycles by the mid-frequencyof the band in cycles.
  • a concave converging, that positive, stepped multiple zone metallic electromagnetic wave lens section of the type disclosed in my aforesaidcopending application and-I. :R..Eaarticle and having a given frequency band width is in effect combined -.With a convex diverging, that is, negative, unstepped multiple -zone metallic electromagnetic wave lens section having the same band width, to form a compound electromagnetic wave lens.
  • Thecomipound lens comprises a plurality of spaced par- .allel metallic plates.
  • One side or face .of the compound lens,corresponding to one side :of the negative lens section, is plane and unstepped; and the opposite side-or face of the compound ilens, corresponding to one side of the positive lens section, is concaveand stepped.
  • the dispersions of the two sections are substantially different .for each frequency of the electromagnetic waves .having frequencies within the broad frequency band to be transmitted through the lens structure whereby an achromatic electromagnetic wave-lens is obtained.
  • achromatic is employed in optics to define a lens which :is free from color or which refracts white light energy Without decomposing it into its :constituent colors.
  • optics-an achromatic lensis composed usually of twoglasses, a-convexand a concave,.theglasses being of substances having different refractive and dispersive powers. '(Quoted definitions.
  • the electromagnetic wave lensestof this invention are, in essence, composed of two portions, one 2portion being the equivalentof-an'optical convex-lens and-the other, the equivalent-of anoptical concave lens, .and the two iportions have dilierent'refractive and dispersivepowers which mutually compensate each other to produce substantially uniform refractive effectsover a broad band'of electromagnetic wave frequencies
  • the devicesof the present invention can .aptlybe termed achromatic electromagnetic wave compoundlenses.
  • the lenses .of :the .present invention are phase advance lenses, i. e., they speed up the wave energy passing through them rather than delaying said energy as optical glass lenses do
  • the physical contours of the electromagnetic wave lenses of this invention are the inverse of the physical contours of the optical lenses. For example, a positive, or converging, electromagnetic wave lens is concave while the corresponding optical glass lens is convex.
  • Figs. 1 and 2 are, respectively, perspective and side views of a microwave system comprising a compound electromagnetic wave lens constructed in accordance with the invention.
  • a translation device I such as a transmitter or receiver, connected by a rectangular wave guide 2 to the throat aperture 3 of the sectoral horn 4.
  • the long dimension of the mouth aperture 5 of the horn 4 is aligned with a focal line 6 of the cylindrical symmetrical compound electromagnetic wave lens I.
  • the lens 1 has an axis or axial plane 8 and comprises a plurality of parallel identical metallic members 9 spaced apart a distance at least one-half wavelength, taken at the longest wavelength in the operating band, and held in position by means of the wooden frame Ill.
  • Each pair of adjacent members 9 and the ai.. dielectric included therebetween constitute a channel II of the compound lens I.
  • each of the metallic plates 9 of the electromagnetic wave lens I comprises in effeet a section I2 having a stepped concave back side I3 and a concave front side I4, and a section I5 having a plane front side I6 and a convex back side I4, the concave front side of section I2 and the convex back side of section I5 being coincident.
  • the circular line I4 does not necessarily represent a physical boundary between the abovedescribed portions of the structure since it will ordinarily be more convenient to construct each plate as a unitary member, but it does denote at least, the common effective boundary of the two adjacent sections I2 and I5.
  • section I5 and the stepped concave side I3 of section I2 constitute, respectively, the front and back faces of the compound electromagnetic wave lens I. Since the shape of section I2 is concave-concavo, this section is, in accordance with the principles explained in my above-mentioned copending application and my I. R. E. article, a positive or converging lens section, whereas section I5 is, by the same principles, a negative or diverging lens section since the shape of this section is plano-convex.
  • the positive section I2 comprises the six stepped zones :1, b, c, d, e and j which have different elliptical curvatures, as explained in my aforesaid copending application and my above-mentioned article. Since the lens structure is vertically symmetrical about the axial plane 8, there will be two each of the stepped zones b, c, d, e, and j, as shown, symmetrically spaced above and below the zone a. The horizontal center line of zone a, of course, lies in plane 8 and zone a is also positioned symmetrically with respect to plane 8 as shown.
  • electromagnetic waves having a frequency included in a given wide frequency band and having a plane wave front I1 and an incoming propagation direction I8, are propagated through the compound electromagnetic wave lens I and are focused on the mouth aperture 5 of the horn 4, as shown by the lines I9.
  • the focal lengths of the positive and negative sections of the electromagnetic wave lens I vary oppositely substantially, as in the case of a compound achromatic optical glass lens when transmittinglight of various colors, 1. e., wavelengths or frequencies.
  • the compound electromagnetic wave lens structuers of the present invention are so aptly designated achromatic.
  • the change with frequency of the angle of convergence of a positive lens either electromagnetic wave or optical is compensated to a substantial extent by an opposite change in the amount of divergence produced by the associated negative lens.
  • the index of refraction n depends upon the wavelength as shown in Equation 3 of my abovementioned copending application or Equation 2 of my above-mentioned paper. This clearly means that if the wavelength is changed to a longer wavelength, n becomes smaller. 11 becoming smaller means that the refractive power of the lens becomes greater so that a positive or converging electromagnetic wave lens has greater convergence and a negative or diverging electromagnetic wave lens has greater divergence.
  • the change in divergence of a lens is equivalent to a change in the focal length and this can be correlated with the band width of the lens. This has been done in Fig. 17 of my above-mentioned application and in Fig. 13 of my abovementioned article. From either of these figures it is seen, for example, that the band width of an unstepped lens 6 wavelengths thick is the same as the band width of a stepped lens having 8 steps.
  • the rate of change of the refractive index with frequency, or so-called dispersion, of the positive electromagnetic wave lens is substantially different, over the given wide frequency band, from the dispersion for the associated neg-- ative lens section, by reason of the fact that the positive lens is stepped and its maximum thickness thus greatly reduced whereas the negative lens is not stepped and therefore has a. relatively much greater maximum thickness. Consequently, when the two portions of the lens are properly proportioned, i. e., to have the same band width as disclosed hereinabove as the frequency varies over the wide band, the focal length of the compound electromagnetic wave lens remains substantially constant, that is, the lens is achromatic.
  • the addition of the negative lens to the positive lens increases the focal length of the combination over that of the positive lens taken alone, so that the compound lens, in one sense, corresponds to a single lens of longer focal length. It may also be added, by way of contrast, that in a compound optical lens the dispersions for the positive lens section and the negative lens sections are different not by reason of the fact that one section is stepped and the other is not, but by reason of the fact that the dielectric materials, usually lass, used in the two lens sections have different dispersion curves.
  • a compound electromagnetic wave, phase advance, metallic lens for focusing waves included in a wide band of Wavelengths and having a given electric polarization, said lens comprising a plurality of metallic members extending parallel to said polarization and spaced apart a distance greater than one-half the longest wavelength in said band, said lens having a stepped concave face and a plane face, said concave and said plane sides being the surfaces which include and are defined by the stepped edges and the linear edges respectively of said plurality of metallic members, the contour line comprising the base line of the steps of said concave edge of each metallic member being a smooth curve of which the linear edge of said member is a chord, whereby said compound lens comprises, in efiect, a positive or converging multiple zone stepped electromagnetic wave, phase advance, metallic lens section and a negative or diverging multiple zone unstepped electromagnetic wave, phase advance, metallic lens section.
  • a compound electromagnetic wave, phase advance, metallic lens for focusing waves included in a wide band of wavelengths and which have a given linear electric polarization said lens comprising a plurality of like flat conductive plate members arranged symmetrically in parallel planes with respect to a transverse axis normal to said plate members, said members being spaced at substantially equal intervals, the interval between each two successive plate members being greater than one-half wavelength of the lowest frequency of said wide band of wavelengths, each said plate member having two oppositely disposed longitudinal edges one of said longitudinal edges of each plate member beingstepped and concave, the other of said edges of each plate member being unstepped, the contour line comprising the base line of the steps of said stepped edge forming with said unstepped edge a portion bounded by an arc of a circle and a chord of said are, whereby said plurality of members form a compound lens comprising a positive, or converging, multiple zone, stepped, electromagnetic wave, phase advance, parallel plate, lens section combined with a negative, or diverging, multiple zone, unstepped

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  • Aerials With Secondary Devices (AREA)
US134788A 1949-12-23 1949-12-23 Achromatic lens antenna Expired - Lifetime US2640154A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
BE500060D BE500060A (en, 2012) 1949-12-23
US134788A US2640154A (en) 1949-12-23 1949-12-23 Achromatic lens antenna
FR1028356D FR1028356A (fr) 1949-12-23 1950-11-24 Lentille achromatique composée pour systèmes d'antennes hertziennes directives
CH296201D CH296201A (de) 1949-12-23 1950-12-11 Achromatische metallene Mikrowellenlinse.
DEW4775A DE838777C (de) 1949-12-23 1950-12-15 Achromatische Verbundlinse fuer Funk-Richtantennen-Systeme

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US134788A US2640154A (en) 1949-12-23 1949-12-23 Achromatic lens antenna

Publications (1)

Publication Number Publication Date
US2640154A true US2640154A (en) 1953-05-26

Family

ID=22465006

Family Applications (1)

Application Number Title Priority Date Filing Date
US134788A Expired - Lifetime US2640154A (en) 1949-12-23 1949-12-23 Achromatic lens antenna

Country Status (5)

Country Link
US (1) US2640154A (en, 2012)
BE (1) BE500060A (en, 2012)
CH (1) CH296201A (en, 2012)
DE (1) DE838777C (en, 2012)
FR (1) FR1028356A (en, 2012)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2834962A (en) * 1954-03-02 1958-05-13 Sperry Rand Corp Wave guide lens
US2841793A (en) * 1953-01-22 1958-07-01 Jr Cornelius Bryant Young Microwave lens
US4194209A (en) * 1977-12-30 1980-03-18 The United States Of America As Represented By The Secretary Of The Air Force Broadband waveguide lens antenna and method of fabrication
DE2941563A1 (de) * 1978-10-13 1980-04-24 Sperry Rand Corp Hohlleiter-anordnung
US4737796A (en) * 1986-07-30 1988-04-12 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Ground plane interference elimination by passive element
WO1992020314A1 (en) * 1991-05-16 1992-11-26 Technology Application Services Method and apparatus for sterilization and/or embalment of corpses and specimens
US20040233122A1 (en) * 2003-05-15 2004-11-25 Espenscheid Mark W. Flat panel antenna array
US20070268198A1 (en) * 2006-05-17 2007-11-22 Marshall Dean R Refractive compact range

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1906546A (en) * 1931-07-10 1933-05-02 Int Communications Lab Inc Echelon grating for reflecting ultra short waves
US2412202A (en) * 1941-06-28 1946-12-10 Bell Telephone Labor Inc Directive radio system
US2442951A (en) * 1944-05-27 1948-06-08 Rca Corp System for focusing and for directing radio-frequency energy
US2562277A (en) * 1946-04-08 1951-07-31 Bell Telephone Labor Inc Metallic lens directive antenna system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1906546A (en) * 1931-07-10 1933-05-02 Int Communications Lab Inc Echelon grating for reflecting ultra short waves
US2412202A (en) * 1941-06-28 1946-12-10 Bell Telephone Labor Inc Directive radio system
US2442951A (en) * 1944-05-27 1948-06-08 Rca Corp System for focusing and for directing radio-frequency energy
US2562277A (en) * 1946-04-08 1951-07-31 Bell Telephone Labor Inc Metallic lens directive antenna system

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2841793A (en) * 1953-01-22 1958-07-01 Jr Cornelius Bryant Young Microwave lens
US2834962A (en) * 1954-03-02 1958-05-13 Sperry Rand Corp Wave guide lens
US4194209A (en) * 1977-12-30 1980-03-18 The United States Of America As Represented By The Secretary Of The Air Force Broadband waveguide lens antenna and method of fabrication
DE2941563A1 (de) * 1978-10-13 1980-04-24 Sperry Rand Corp Hohlleiter-anordnung
US4737796A (en) * 1986-07-30 1988-04-12 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Ground plane interference elimination by passive element
WO1992020314A1 (en) * 1991-05-16 1992-11-26 Technology Application Services Method and apparatus for sterilization and/or embalment of corpses and specimens
US20040233122A1 (en) * 2003-05-15 2004-11-25 Espenscheid Mark W. Flat panel antenna array
US7084836B2 (en) 2003-05-15 2006-08-01 Espenscheid Mark W Flat panel antenna array
US20070268198A1 (en) * 2006-05-17 2007-11-22 Marshall Dean R Refractive compact range
US7541994B2 (en) * 2006-05-17 2009-06-02 Raytheon Company Refractive compact range

Also Published As

Publication number Publication date
FR1028356A (fr) 1953-05-21
BE500060A (en, 2012)
CH296201A (de) 1954-01-31
DE838777C (de) 1952-05-12

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