GB2160021A - Antenna - Google Patents

Antenna Download PDF

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Publication number
GB2160021A
GB2160021A GB08414285A GB8414285A GB2160021A GB 2160021 A GB2160021 A GB 2160021A GB 08414285 A GB08414285 A GB 08414285A GB 8414285 A GB8414285 A GB 8414285A GB 2160021 A GB2160021 A GB 2160021A
Authority
GB
United Kingdom
Prior art keywords
antenna
housing
cavity
absorber material
back plate
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.)
Granted
Application number
GB08414285A
Other versions
GB2160021B (en
GB8414285D0 (en
Inventor
Geoffrey Taylor
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.)
Decca Ltd
Original Assignee
Decca Ltd
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 Decca Ltd filed Critical Decca Ltd
Priority to GB08414285A priority Critical patent/GB2160021B/en
Publication of GB8414285D0 publication Critical patent/GB8414285D0/en
Publication of GB2160021A publication Critical patent/GB2160021A/en
Application granted granted Critical
Publication of GB2160021B publication Critical patent/GB2160021B/en
Expired legal-status Critical Current

Links

Classifications

    • 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
    • H01Q13/10—Resonant slot antennas
    • H01Q13/18—Resonant slot antennas the slot being backed by, or formed in boundary wall of, a resonant cavity ; Open cavity antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H01Q9/27—Spiral antennas

Landscapes

  • Aerials With Secondary Devices (AREA)
  • Details Of Aerials (AREA)

Abstract

In an antenna having a planar transmission/reception element (6) closing a cavity (3) in a housing (1) the cavity (3) contains absorber material (21) which serves to support the element (6) against movement into the cavity (3). Such a construction gives good support for the element (6) during use under conditions of externally applied pressures while having the minimum effect on the normal operation of the antenna. <IMAGE>

Description

SPECIFICATION An antenna This invention relates to an antenna, and particularly to an antenna having a planar transmission/ reception element closing a cavity in a housing.
An antenna is known in which the element is a printed circuit board comprising an insulating substrate having conductive members in the shape of two interwound spirals, printed on the substrate.
According to this invention there is provided an antenna having a planar transmission/reception element closing a cavity in a housing, in which the cavity contains absorber material arranged to sup port the element against movement into the cavity.
An antenna embodying this invention will now be described by way of example with reference to the drawing which is a sectional view through the antenna.
The antenna comprises a housing 1 made of tita nium and circular in cross-section, having at one end a relatively small diameter closed end portion 2 and at the other end an axially aligned relatively large diameter open end portion 3. The portions 2 and 3 are separated by an internal back plate 4 se cured to the housing 1 by means of screws 5.
The open end of the housing portion 3 is closed by a planar element 6 in the form of a printed cir cuit board comprising an insulating substrate hav ing conductive members (not shown) in the form of two interwound spirals, printed on its outer sur face.
The board 6 is held in position by an end cap ra dome 7 formed of Noryl (trade mark) which is in screw-thread engagement with the housing 1 as shown at 8, with an interposed O-ring sealing member 9 serving to prevent the ingress of mo isutre into the housing 1.
Passing through the end wall 10 of the housing portion 2 in hermetically sealed manner are two co-axial cable connectors 11 and 12, the inner ends of the connectors being received in recesses 13 in the end wall 10.
The connector 11 serves for providing connec tions to the element 6 and is connected within the housing portion 2 to a balun 14 which is in turn connected by way of a double-sided printed circuit board 15 to the two conductors of the element 6.
The board 15 passes through a hole 16 in the back plate 4, and also projects through a hole 17 in the element 6 into a recess 18 forward in the end cap 7. Conductors on the board 15 are connected to the conductors of the element 6 in a manner which permits movement of the element 6 relative to the board 15 in the direction of the axis of the antenna, such movement being caused by, for example, pressure and/or temperature changes acting on the antenna.
The connector 12 serves for connection to a BITE probe 19 which passes through the back plate 4 and terminates with an exposed end spaced from the element 6.
The balun 14 is secured to the back plate 4 and is also supported by the end wall 10 of the housing portion 2, a disc 20 of surface wave absorber material being interposed between the balun 14 and the wall 10.
The cavity in the housing portion 3 between the back plate 4 and the element 6 contains two blocks 21 of load-bearing, syntactic filled honeycombstructure, wide band absorber material. A suitable absorber material for the blocks 21 is a phenolic nylon covered with a carbon-epoxy resistive ink coating, such a material being available from Advanced Absorber Products Inc. of Amesbury, Massachusetts, United States of America.
A central one of the blocks 21 directly supports the element 6, this block 21 resting on a raised central portion 22 of the back plate 4. The other outer block 21 is annular in shape, surrounding the central block 21, and rests on the back plate 4 while supporting the element 6 by way of an annular member 23 formed of syntatic material.
Such a construction of antenna gives good support for the element 6 against externally applied pressures while having the minimum effect on the normal operation of the antenna.
A sleeve 24 of surface wave absorber material is provided about the member 23 and part of the outer surface of the outer annular block 21, while a disc 25 of double-sided adhesive material can be provided between the under-surface of the element 6 and the blocks 21.
In an alternative construction the surface of the back plate 4 facing the housing portion 3 is planar there being a single disc 21 of absorber material all of which is spaced from the element array 6 by a single disc-shaped member 23.
The front outer face of the disc 21 may be planar as shown, or otherwise it may be formed with concentric annular steps, or of conical profile, or any other suitable contour, symmetrical about its central axis.
1. An antenna having a planar transmission/reception element closing a cavity in a housing, in which the cavity contains absorber material arranged to support the element against movement into the cavity.
2. An antenna as claimed in Claim 1, in which the absorber material is in the form of a single block and supports the element by way of a nonabsorbing member of syntactic material.
3. An antenna as claimed in Claim 1, in which the absorber material is in the form of two separate blocks, a first central block directly supporting the element over an area around its centre, and the second block having the form of an annulus, surrounding the first block and supporting the element by way of a non-absorbing annular member of syntactic material.
4. An antenna as claimed in any preceding claim, in which the cavity is defined at its side remote from the element by a back plate which supports the absorber material, and which separates the cavity from another closed end portion of the housing.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION An antenna This invention relates to an antenna, and particularly to an antenna having a planar transmission/ reception element closing a cavity in a housing. An antenna is known in which the element is a printed circuit board comprising an insulating substrate having conductive members in the shape of two interwound spirals, printed on the substrate. According to this invention there is provided an antenna having a planar transmission/reception element closing a cavity in a housing, in which the cavity contains absorber material arranged to sup port the element against movement into the cavity. An antenna embodying this invention will now be described by way of example with reference to the drawing which is a sectional view through the antenna. The antenna comprises a housing 1 made of tita nium and circular in cross-section, having at one end a relatively small diameter closed end portion 2 and at the other end an axially aligned relatively large diameter open end portion 3. The portions 2 and 3 are separated by an internal back plate 4 se cured to the housing 1 by means of screws 5. The open end of the housing portion 3 is closed by a planar element 6 in the form of a printed cir cuit board comprising an insulating substrate hav ing conductive members (not shown) in the form of two interwound spirals, printed on its outer sur face. The board 6 is held in position by an end cap ra dome 7 formed of Noryl (trade mark) which is in screw-thread engagement with the housing 1 as shown at 8, with an interposed O-ring sealing member 9 serving to prevent the ingress of mo isutre into the housing 1. Passing through the end wall 10 of the housing portion 2 in hermetically sealed manner are two co-axial cable connectors 11 and 12, the inner ends of the connectors being received in recesses 13 in the end wall 10. The connector 11 serves for providing connec tions to the element 6 and is connected within the housing portion 2 to a balun 14 which is in turn connected by way of a double-sided printed circuit board 15 to the two conductors of the element 6. The board 15 passes through a hole 16 in the back plate 4, and also projects through a hole 17 in the element 6 into a recess 18 forward in the end cap 7. Conductors on the board 15 are connected to the conductors of the element 6 in a manner which permits movement of the element 6 relative to the board 15 in the direction of the axis of the antenna, such movement being caused by, for example, pressure and/or temperature changes acting on the antenna. The connector 12 serves for connection to a BITE probe 19 which passes through the back plate 4 and terminates with an exposed end spaced from the element 6. The balun 14 is secured to the back plate 4 and is also supported by the end wall 10 of the housing portion 2, a disc 20 of surface wave absorber material being interposed between the balun 14 and the wall 10. The cavity in the housing portion 3 between the back plate 4 and the element 6 contains two blocks 21 of load-bearing, syntactic filled honeycombstructure, wide band absorber material. A suitable absorber material for the blocks 21 is a phenolic nylon covered with a carbon-epoxy resistive ink coating, such a material being available from Advanced Absorber Products Inc. of Amesbury, Massachusetts, United States of America. A central one of the blocks 21 directly supports the element 6, this block 21 resting on a raised central portion 22 of the back plate 4. The other outer block 21 is annular in shape, surrounding the central block 21, and rests on the back plate 4 while supporting the element 6 by way of an annular member 23 formed of syntatic material. Such a construction of antenna gives good support for the element 6 against externally applied pressures while having the minimum effect on the normal operation of the antenna. A sleeve 24 of surface wave absorber material is provided about the member 23 and part of the outer surface of the outer annular block 21, while a disc 25 of double-sided adhesive material can be provided between the under-surface of the element 6 and the blocks 21. In an alternative construction the surface of the back plate 4 facing the housing portion 3 is planar there being a single disc 21 of absorber material all of which is spaced from the element array 6 by a single disc-shaped member 23. The front outer face of the disc 21 may be planar as shown, or otherwise it may be formed with concentric annular steps, or of conical profile, or any other suitable contour, symmetrical about its central axis. CLAIMS
1. An antenna having a planar transmission/reception element closing a cavity in a housing, in which the cavity contains absorber material arranged to support the element against movement into the cavity.
2. An antenna as claimed in Claim 1, in which the absorber material is in the form of a single block and supports the element by way of a nonabsorbing member of syntactic material.
3. An antenna as claimed in Claim 1, in which the absorber material is in the form of two separate blocks, a first central block directly supporting the element over an area around its centre, and the second block having the form of an annulus, surrounding the first block and supporting the element by way of a non-absorbing annular member of syntactic material.
4. An antenna as claimed in any preceding claim, in which the cavity is defined at its side remote from the element by a back plate which supports the absorber material, and which separates the cavity from another closed end portion of the housing.
5. An antenna as claimed in Claim 4, in which connections are made to the element by means of a connector passing through an end wall of said other portion of the housing, the connector providing connections to a balun contained in said other portion of the housing, the balun being connected to conductors of the element by means of a printed circuit board extending from the balun to the element through a hole in the absorber mate dal
6. An antenna as claimed in Claim 5, in which a member of surface wave absorber material is sandwiched between the balun and said end wall.
7. An antenna as claimed in any preceding claim, in which the element is held in position closing the cavity in the housing by an end cap secured to the housing covering the element.
8. An antenna as claimed in Claim 7, in which the end cap is in screw-thread engagement with the housing.
9. An antenna as claimed in any preceding claim, in which the element is a printed circuit board comprising an insulating substrate having two interwound spiral conductors printed on the outer surface thereof.
10. An antenna as claimed in any preceding claim, in which the absorber material is a honeycomb structure of phenolic nylon covered with a carbon-epoxy resistive ink coating.
11. An antenna as claimed in any preceding claim, which is sealed against the ingress of moisture into the housing.
12. An antenna substantially as hereinbefore described with reference to and as shown in the drawing.
GB08414285A 1984-06-05 1984-06-05 Antenna Expired GB2160021B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB08414285A GB2160021B (en) 1984-06-05 1984-06-05 Antenna

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB08414285A GB2160021B (en) 1984-06-05 1984-06-05 Antenna

Publications (3)

Publication Number Publication Date
GB8414285D0 GB8414285D0 (en) 1984-07-11
GB2160021A true GB2160021A (en) 1985-12-11
GB2160021B GB2160021B (en) 1987-12-23

Family

ID=10561936

Family Applications (1)

Application Number Title Priority Date Filing Date
GB08414285A Expired GB2160021B (en) 1984-06-05 1984-06-05 Antenna

Country Status (1)

Country Link
GB (1) GB2160021B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393875A1 (en) * 1989-04-18 1990-10-24 Texas Instruments Incorporated A compact multi-polarized broadband antenna

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1358483A (en) * 1973-04-02 1974-07-03 Wilkes Co Ltd D A Radio aerials for motor vehicles

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1358483A (en) * 1973-04-02 1974-07-03 Wilkes Co Ltd D A Radio aerials for motor vehicles

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0393875A1 (en) * 1989-04-18 1990-10-24 Texas Instruments Incorporated A compact multi-polarized broadband antenna

Also Published As

Publication number Publication date
GB2160021B (en) 1987-12-23
GB8414285D0 (en) 1984-07-11

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Legal Events

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PCNP Patent ceased through non-payment of renewal fee