Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
• • 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
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole
  • H01Q9/42—Resonant antennas with feed to end of elongated active element, e.g. unipole with folded element, the folded parts being spaced apart a small fraction of the operating wavelength
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/12—Supports; Mounting means
  • H01Q1/22—Supports; Mounting means by structural association with other equipment or articles
  • H01Q1/24—Supports; Mounting means by structural association with other equipment or articles with receiving set
  • H01Q1/241—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM
  • H01Q1/242—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use
  • H01Q1/243—Supports; Mounting means by structural association with other equipment or articles with receiving set used in mobile communications, e.g. GSM specially adapted for hand-held use with built-in antennas
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
  • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support

Definitions

• the present invention relates to an antenna device according to the preamble of claim 1.
• the invention also relates to a method for manufacturing an antenna device according to the preamble of claim 12.
• Common techniques in manufacturing of antenna elements includes either the use a thin self supportive metal sheet having a desired shape, or creating a radiating pattern in a metal coating, supported by a substrate, e.g. by etching, or applying a radiating pattern to a substrate, e.g. by screen printing conducting paint.
• These types of antenna elements are usually flexible and may easily be mounted to a mobile telephone.
• the metal sheet, or radiating pattern, normally used is made of copper or a copper alloy.
• the copper oxidises over time and normally there is a need to have a portion of the antenna element connected to some other equipment, e.g. a conductive connection.
• This connection portion may be plated with another metal to avoid the oxidation and to obtain a good contact with low contact resistance, by for instance gold. This is an expensive process, since gold is expensive.
• DD 146 873 there is described a device for improving the performance of an electrical switch by coating the copper with graphite.
• the oxidation of the copper is prevented and a good contact between two adjacent circuits on a PCB may be achieved by using a push-button switch over the graphite coated adjacent circuits.
• the present invention seeks to provide an improved antenna device .
• an antenna device as specified in claim 1.
• the invention is also directed to a method by which an embodiment of the desired antenna device is manufactured.
• An advantage of having a graphite compound at least partially coating an antenna device in the present invention is that it prevents the coated conductive pattern to oxidise.
• Another advantage of having the graphite coating in the present invention is that it provides a protective layer for the antenna element, since the graphite has sliding properties .
• an advantage with an embodiment of the present invention is that the graphite compound provides a contact portion with a low contact resistance compared to without a graphite compound, since the graphite compound prevents the coated conductive pattern to oxidise and the soft graphite compound shapes it self around a contact device, e.g. a contact pin or waveguide shim.
• the inventive antenna device can be used in MID technology with decreased risk of oxidation of conductors .
• the soft graphite compound may be applied to a conductive pattern, which is arranged on a flexible substrate, which is to be bent.
• An advantage with t s manufacturing method is that the manufacturing steps are reduced when using the graphite compound as a film, where the graphite compound is applied in the shape of the conductive pattern.
• Fig. 1 shows a cross-section of an inventive antenna device.
• Fig. 2a shows a top view of a first embodiment of the present invention.
• Fig. 2b shows a cross section of the first embodiment along a line A-A in Fig. 2a.
• Fig. 3a shows a top view of a second embodiment of the present invention.
• Fig. 3b shows a cross section of the second embodiment along a line B-B in Fig. 3a.
• Fig. 4a-4d shows manufacturing steps for an embodiment of the present invention.
• Fig. 5 shows an antenna device being mounted inside an antenna assembly.
• the present invention corresponds to graphite coating of surfaces to electrically conductive structures, especially for the following areas of mobile or hand held telecommunication devices :
• These antennas may have a two or three dimensional geometry.
• the antenna pattern (which is at least partially coated with graphite) may be applied on a flat or curved surface.
• the conductive structure is coated at least partially with graphite, for instance through screen printing techniques. By doing this, contact points with high contact performance may be achieved without having to gold plate a part of the surface of the conductive structure.
• the graphite is a bit soft and can form it self after a contacting device, e.g. contact pin or waveguide shim, which is provided to connect the antenna device to a transceiver circuit. Furthermore, good contact characteristics with other contact devices of different materials may be achieved.
• a contacting device e.g. contact pin or waveguide shim
• the part of the conductive structure that is coated with graphite is also protected against oxidation, and that part is also protected against external damage (such as scratching or wearing) by the graphite itself and its lubricating (or sliding) properties.
• the protection against external damage may be useful when mounting an antenna device comprising a conductive structure covered with graphite, as illustrated in Fig. 5.
• Fig. 1 shows a cross-section of an inventive antenna device 10, comprising a substrate 11, on which a conductive structure 12, or pattern, is formed. A graphite coating 13 is arranged on top of the conductive pattern 12.
• Fig. 2a shows a top view of an antenna device 20, comprising a substrate 21 and a conductive pattern 22 having a graphite coating arranged on top of the complete conductive pattern 22.
• the antenna device is provided with a contact portion 24.
• a cross section of the antenna device 20 is shown in Fig. 2b, where the substrate is denoted 21 and the conductive pattern is denoted 22.
• On top of the conductive pattern 22 is a graphite 23 coating arranged.
• a method for manufacturing this antenna device 20 is illustrated in Fig. 4a-4d. The size of the illustrated antenna device 20 is larger than the actual size.
• Fig. 3a shows an antenna device 30 mounted inside a telephone cover 33. Only the upper part of the cover is shown and the lower part is indicated by the dashed lines.
• the antenna device 30 comprises a metal sheet shaped into a conductive pattern 31 and a partial graphite coating 32, illustrated by the hatch pattern, which is arranged on a part of the conductive pattern 31 to form a contact area 34.
• a contact pin or waveguide shim may easily be brought into contact with the conductive pattern 31 via said graphite coating 32.
• the metal sheet containing the conductive pattern 31 is flexible and may be applied inside the telephone cover and follow the interior shape of the cover 33, i.e. a curved shape, as shown in Fig. 3b.
• Fig. 3b is a cross section taken along the line B-B in Fig. 3a.
• the conductive pattern 31 of the antenna device 30 is bent to follow the shape of the cover 33. This way the antenna device takes minimum space.
• the graphite coating 32 is, in this example, only applied to the contact area 34 of the conductive pattern 31 of the antenna device 30.
• the antenna device in this example is a PIFA (Planar Inverted F-Antenna) .
• a ground plane 35 is illustrated by dashed lines, which ground plane is separated from the antenna device 30.
• the space 36 between the ground plane 35 and the antenna device 30 may be filled with a dielectric material or by air.
• a graphite coating may naturally be applied to the whole surface of the conductive pattern in the above described example.
• a such coating may provide a protection to the antenna from external damages in form of scratching or wearing .
• Fig. 4a-4d illustrates a manufacturing method for the first embodiment shown in Fig. 2a and 2b.
• the method starts by selecting a suitable substrate 40, the substrate could be a flexible self-adhesive plastic film, a PCB (Printed Circuit Board) or any other type of non- conductive material, flexible or rigid.
• a suitable substrate 40 the substrate could be a flexible self-adhesive plastic film, a PCB (Printed Circuit Board) or any other type of non- conductive material, flexible or rigid.
• a suitable metal 41 having good conductibility e.g. copper, copper alloy or silver polymer is then arranged to the substrate 40.
• These metals are relatively cheap and easy to use, but experience a major drawback since they have the inherent property of oxidising the surface of the metal .
• a film 42 is applied to the metal 41.
• the film 42 is made of graphite or a graphite compound and the film 42 may have a meandering shape as shown in Fig. 2a, or any other desired antenna shape, e.g. like the antenna shown in Fig. 3.
• the uncovered metal 43 i.e. metal not covered by the film 42, is then removed by e.g. etching, using a medium reacting essentially with the metal coating not covered by the film.
• a medium reacting essentially with the metal coating not covered by the film is presented in Fig. 4d where the substrate 40 carries a conductive pattern 44 which is covered by a protective coating 42 made of graphite or a graphite compound.
• Previous known techniques for manufacturing antenna devices comprises the first step of selecting a suitable substrate and arranging a metal coating on top of the substrate .
• the following step is to apply a film, which have the desired radiating pattern.
• the shape of the conductive pattern is thereafter obtained by removing the metal not covered by the film.
• the film is removed from the conductive pattern and the antenna device is completed.
• this step there may be additional coatings applied to contact portions to reduce the contact resistance between the conductive pattern and a contact device, which is connected to a transceiver circuit. Normally this coating is a gold plating.
• FIG. 5 shows an antenna device 20 mounted on a conically shaped rod 51.
• the antenna device 20 may be attached using an adhesive material.
• the rod is thereafter inserted into a case 52 and the rod 51 is attached to the case 52 using snap fittings 53, 54. Due to the lubricating properties of the graphite, which cover the conductive pattern 22 of the antenna device 20, the rod (with the attached antenna device) is easily mounted without any frictionally damages.
• the antenna assemlby is thereafter mounted to a hand held telecommunication device, such as a mobile telephone.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Details Of Aerials (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20278277

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (15)

Citations (2)

Family Cites Families (4)

• 2000
  • 2000-01-31 SE SE0000290A patent/SE516106C2/sv not_active IP Right Cessation
• 2001
  • 2001-01-26 US US10/169,914 patent/US6831606B2/en not_active Expired - Fee Related
  • 2001-01-26 AU AU30683/01A patent/AU3068301A/en not_active Abandoned
  • 2001-01-26 CN CNB018041884A patent/CN1215599C/zh not_active Expired - Fee Related
  • 2001-01-26 EP EP01902919A patent/EP1254489A1/en not_active Withdrawn
  • 2001-01-26 WO PCT/SE2001/000157 patent/WO2001057951A1/en not_active Application Discontinuation
  • 2001-01-26 KR KR1020027008615A patent/KR100563606B1/ko not_active IP Right Cessation

Patent Citations (2)

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