GB581746A - Reducing the intensity of electro-magnetic waves reflected by reflecting objects - Google Patents

Reducing the intensity of electro-magnetic waves reflected by reflecting objects

Info

Publication number
GB581746A
GB581746A GB1396243A GB1396243A GB581746A GB 581746 A GB581746 A GB 581746A GB 1396243 A GB1396243 A GB 1396243A GB 1396243 A GB1396243 A GB 1396243A GB 581746 A GB581746 A GB 581746A
Authority
GB
United Kingdom
Prior art keywords
recesses
wave
depth
length
waves
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
Application number
GB1396243A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Priority to GB1396243A priority Critical patent/GB581746A/en
Priority to FR950268D priority patent/FR950268A/en
Publication of GB581746A publication Critical patent/GB581746A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q17/00—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
    • H01Q17/008—Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems with a particular shape
    • 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
    • H01Q15/14—Reflecting surfaces; Equivalent structures

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Aerials With Secondary Devices (AREA)

Abstract

581,746. Radio reflection from surfaces, preventing. COLLARD, J. Aug. 26, 1943, No. 13962. [Class 40 (v)] An object normally detectable by radiolocation is rendered substantially non-reflective by dividing its surface into a multiplicity of small areas alternately raised and depressed a distance equal to a quarter wave-length or an odd multiple thereof, so that waves reflected by one set of areas are in opposite phase to those reflected by the other. As shown in Fig. 2, the surface, which may be that of an aeroplane wing or fuselage, has alternate raised areas 4 and recesses 5 which may be in the form of cylindrical cups, a quarter wave-length deep. The recesses may be filled with solid dielectric material to reduce air friction. If material of high dielectric constant is used, e.g. titanium dioxide, the actual depth of the recesses is reduced although that depth still represents electrically a quarter wave-length. To render the object substantially non-reflective over a wide band of wave-lengths, some of the recesses may be of a depth suited to one wave-length and others to other wave-lengths. The area of each recess should be as small as possible but should not be so reduced that the recesses considered as wave guides would not permit the passage of the waves in use. In Fig. 3, the recesses 5 are formed in a sheet of dielectric material 7 which covers the outer surface 4 of the object. The depth of the recesses is such that waves travelling through the dielectric a distance equal to twice the depth of a recess are half a wave-length behind those travelling the same distance in air. The recesses mav be filled with a substance having a different dielectric constant from that of the sheet. The invention is applicable to reflecting objects other than aircraft, for example submarines or the tops of buildings.
GB1396243A 1943-08-26 1943-08-26 Reducing the intensity of electro-magnetic waves reflected by reflecting objects Expired GB581746A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1396243A GB581746A (en) 1943-08-26 1943-08-26 Reducing the intensity of electro-magnetic waves reflected by reflecting objects
FR950268D FR950268A (en) 1943-08-26 1946-08-22 Reduced intensity of electromagnetic waves reflected from reflective objects

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB1396243A GB581746A (en) 1943-08-26 1943-08-26 Reducing the intensity of electro-magnetic waves reflected by reflecting objects

Publications (1)

Publication Number Publication Date
GB581746A true GB581746A (en) 1946-10-23

Family

ID=10032527

Family Applications (1)

Application Number Title Priority Date Filing Date
GB1396243A Expired GB581746A (en) 1943-08-26 1943-08-26 Reducing the intensity of electro-magnetic waves reflected by reflecting objects

Country Status (2)

Country Link
FR (1) FR950268A (en)
GB (1) GB581746A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2615126A (en) * 1948-12-03 1952-10-21 Paul A Kennebeck Narrow beam receiving antenna
GB2163296A (en) * 1977-09-01 1986-02-19 Elliott Bros Reducing radar reflections
GB2184861A (en) * 1985-11-08 1987-07-01 Sec Dep For Trade & Industry T Metallic surface with projections filled with absorbent material
EP0446408A1 (en) * 1990-03-12 1991-09-18 TRUBE & KINGS KG Wall element minimizing radar reflections

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2615126A (en) * 1948-12-03 1952-10-21 Paul A Kennebeck Narrow beam receiving antenna
GB2163296A (en) * 1977-09-01 1986-02-19 Elliott Bros Reducing radar reflections
GB2184861A (en) * 1985-11-08 1987-07-01 Sec Dep For Trade & Industry T Metallic surface with projections filled with absorbent material
EP0446408A1 (en) * 1990-03-12 1991-09-18 TRUBE & KINGS KG Wall element minimizing radar reflections

Also Published As

Publication number Publication date
FR950268A (en) 1949-09-22

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