Classifications

• • 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
  • H01Q9/28—Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines
  • H01Q9/285—Planar dipole
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/08—Means for collapsing antennas or parts thereof
  • H01Q1/085—Flexible aerials; Whip aerials with a resilient base
• • 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
• • 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
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/44—Details of, or arrangements associated with, antennas using equipment having another main function to serve additionally as an antenna, e.g. means for giving an antenna an aesthetic aspect
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/30—Arrangements for providing operation on different wavebands
  • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
  • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
  • H01Q5/321—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors within a radiating element or between connected radiating elements

Definitions

• the present invention relates to antennas for transmitting and receiving high frequency radio waves.
• the antenna is an important component in portable transceiver equipment and affects the total transmission performance in wireless communication.
• Antennas that are larger in relation to the wavelengths for which the antennas are intended can transmit and receive radio signals better in desired wave propagation directions and have a better efficiency.
• the use of such antennas can increase the number of simultaneous users in a base station cell for mobile telephony by im- proved radio coverage and can also extend both the connection time and the standby time of the equipment.
• a better antenna when receiving signals results in that the power of the transmitter can be accordingly reduced, this in time implying that interference related to transmission (EMC
• ElectroMagnetic Compatibility in apparatus that is particularly sensitive to interference, e.g. in hospitals and in aircraft, are lower.
• a better antenna that is used in regions having bad coverage makes the connection to the network safer.
• an FM radio station and receivers of signals therefrom can be made significantly larger.
• an antenna for receiving/transmitting high frequency radio signals can be ribbon- or strip-shaped and then includes a strip-shaped, flexible carrying, electrically isolating element.
• An electrically conducting pattern is arranged on the carrying element.
• the carrying element can have some other suitable design, for example have the configuration of a conventional polymer card or credit card made from uniform polymer material.
• the electrically conducting pattern forms the very antenna conductor that can also be strip-shaped having a straight or curved shape.
• the carrying element can be designed to include a longitudinal, centrally located folding line along which the carrying element can be folded together and be folded out. A coupling place for connecting the antenna conductor to a connection cable or connection line is then suitably arranged on the side of the carrier that is hidden when the carrier is folded together.
• the carrying element can be flexible or comprise a stiff substrate.
• a flexible substrate it can include a pressure sensitive adhesive on a surface for attaching it to a suitable surface.
• a stiff substrate can include a suction cup directly made in the material of the substrate. It allows a temporary attachment of the antenna to suitable surfaces.
• connection place between an antenna conductor and a connection line or transmission cable can include an electrically conducting plate or surface for cooperation with a connector including a corresponding plate or area of the connection line for forming a capacitor, which is capable of coupling signals between the antenna conductor and the connection line.
• One of the electrically conducting plates is thus directly connected to the antenna conductor and is mounted on or in the carrying element, whereas the cooperating electrically conducting plate of the connector is directly coupled to the connection line.
• the capacitor has a dielectric that can be pri- marily constituted of material of the carrying element.
• the connector can include suitable detachable means, such as means comprising a suction cup or magnet, for attaching or retaining the connector and thereby the connection line to/at the carrying element of the antenna.
• Such a suction cup can enclose or be located around the electrically conducting plate of the connector.
• the connector includes a magnet
• it suitably cooperates with an area of magnetic material, in particular soft magnetic material, arranged at or in the surface of the carrying element of the antenna.
• the area of magnetic material can be arranged at or cover the electrically conducting area connected to the antenna conductor. It can also form or be part of or include the electrically conducting area.
• connection line can be designed in a manner similar to the antenna and can then in- elude a flexible carrying element comprising an electric conductor arranged thereon or therein for forming a transmission line of microstrip type. It can include a connector designed as a flexible carrying element that is attached to the carrying element of the antenna and that includes at least one electrically conducting area for forming the capacitor plate of the connection line.
• the electrically conducting pattern can form a plurality of antenna conductors separated from each other, each including an electrically conducting area for cooperation with a connector at a connection line.
• a part of the carrying element including a complete antenna conductor including its electrically conducting area can then be severed from the rest of the carrying element and be mounted or used at a suitable place.
• the carrying element is then suitably capable of being rolled up.
• the antenna conductor and/or the electrically conducting pattern of which the antenna conductor is a part can be designed to form a decorative picture for visually showing information, for example a figure including alphabetic signs. Such a picture can then be mounted on or in the housing of the apparatus together with which the antenna is to be used.
• the electrically conducting pattern can also include at least one filter structure of LC-type dimensioned to give an interrupt in the antenna conductor for frequencies within a high frequency band but not for frequencies within a low frequency band.
• a filter structure can include an inductance conductor having an adapted width and including a path which is formed to have a configuration adapted considering parasite capacitances of the conductor, whereby the inductance conductor provides both . he inductance and the capacitance required to form the LC- filter.
• the antenna main conductor can have a free portion that at a transition position continues into a transmission line portion.
• the latter one is shielded by upper and lower metal layers that are electrically connected to each other and that are electri- cally isolated from a transmission line portion and from the transition position over an adapted length and are folded around or back about dielectric, electrically isolating layers.
• the transmission line portion can be given a predetermined impedance.
• the upper and lower metal layers are suitably strip-shaped, are located parallel to each other and have a width that is substantially larger than the width of the antenna main conductor.
• the width of the metal layers can be at least five times and preferably eight times the widths of the antenna main conductor.
• the upper metal layer is suitably placed on the same side of the carrying element as the antenna main conductor and the lower metal layer on an opposite side of the carrying element in relation to the antenna main conductor.
• the length of the portions folded back is substantially equal to the length of the free portion and these lengths are advantageously substantially equal to a fourth of the wavelengths within the wavelength band for which the antenna is intended.
• the transmission line portion can be terminated at an inner connection area for connection to a transmission cable and the upper and lower metal layers can be connected to an outer connection area for connection to the same transmission cable so that the outer connection area surrounds the inner connection area.
• the inner and outer connection areas are suitably designed for capacitive coupling to conductors in a transmission cable.
• Such a transmission cable can at its connection end be retained at the inner and outer connection areas by magnetic forces.
• the im er and outer connection areas can then include magnetic material, for example soft magnetic material, for cooperation with magnetic material at the end of a transmission cable that can for example be permanent magnet type.
• the antenna described herein can among others have the following advantages:
• - Fig. 1 is a view from above or from the front of a strip-shaped antenna
• - Fig. 2a is a view from above or from the front of a strip-shaped antenna including a straight main conductor intended for two frequency bands,
• Fig. 2b is a view similar to Fig. 2a of an antenna including a meander-shaped main conductor
• - Fig. 3 is a view of a strip-shaped antenna intended for three frequency bands mounted on a window pane of a motorcar
• - fig 4. is a sectional view of a coupling position between a strip-shaped antenna and a cable in- eluding a connector comprising a suction cup,
• Fig. 5 is a sectional view similar to Fig. 4 but including a connector comprising magnets,
• - Fig. 6 is a perspective view of a strip-shaped antenna including a foldable portion
• Fig. 7 is a perspective view of the antenna of Fig. 6 mounted on a window pane
• - Fig. 8 is part view from the top or from the front of a strip-shaped dipole antenna connected to a feeding cable including balanced conductors,
• Fig. 9 is a part view similar to Fig. 8 but connected to a transmission line of microstrip type
• Fig. 10a is a part view of a dipole antenna including coupling areas of an alternative design
• - Fig. 10b is a view from the bottom of a connector including a suction cup or magnet for connection to the dipole antenna of Fig. 10a
• - Fig. 11 is a part view similar to Fig. 10a including coupling areas of a circular configuration
• Fig. 1 lb is a view from the bottom of a connector including a magnet for connecting to the dipole antenna of Fig. 11a,
• Fig. 1 lc is a view from the side of the connector of Fig. l ib,
• - Fig. 12a is a perspective view of antennas arranged on a long, flexible strip rolled up to a coil
• - Fig. 12b is a perspective view of the coil of Fig. 12a placed in a conventional tape holder
• Fig. 12c is a perspective view of transmission lines arranged on a long, flexible strip rolled up to form a coil that is placed in a conventional tape holder,
• Fig. 13a is a schematic picture illustrating the coupling between a transmission line of micro- strip type and a dipole antenna including a meander-shaped main conductor.
• FIG. 13b and 13c are schematics illustrating coupling between a transmission line of microstrip type and a dipole antenna including a filter in the main conductor for receiving/transmitting in two frequency bands,
• Figs. 14a and 14b are schematics illustrating a dipole antenna and a monopole antenna respec- tively including a strip-shaped main conductor designed as a logotype,
• Figs. 14c and 14d are schematics illustrating a monopole antenna including a strip-shaped main conductor in which cut-out portions form a logotype
• - Figs. 15a and 15b are plan views of a monopole antenna and a dipole antenna respectively including a strip-shaped main conductor arranged on a substrate of type credit card
• - Fig. 15c is a cross-sectional view of the antennas of Figs. 15a and 15b,
• Fig. 16a is a plan view of an antenna including a strip-shaped main conductor designed as a "sleeve antenna",
• Fig. 16b is a cross-sectional view of the antenna of Fig. 16a
• Fig. 17a is a schematic plan view illustrating parasite capacitances of inductance conductors connected in an antenna main conductor
• FIG. 17b and 17c are schematics illustrating inductor conductors of different designs giving different values of inductance and capacitance of the inductor conductor.
• the antenna shown in Fig. 1 includes a substrate or carrying element 1 that in this embodi- ment is flexible and can include a polymer strip which can be thin and have a thickness of typically 0.1 - 0.5 mm.
• the strip-shaped substrate can be made from for example polyimide such as Kapton and carries or comprises an electric conductor or conductor path 3 which can be located at one of the surfaces of the carrier or be imbedded in the carrier and is made from a suitable, electrically well conducting material.
• the conductor is generally tape- or strip-shaped and can have a lower ground plane, not shown, so that a microstrip structure is obtained, and it can as illustrated, in the preferably case, have a straight shape but it can also be meander-shaped or designed in other ways such as a curve consisting of straight line segments and/or including curved portions, compare Fig. 2b.
• the conductor can include capacitive and inductive elements for one, two or more frequency bands.
• An inductive element working as an antenna filter for one frequency band is illustrated at 4 in Fig. 1 and can as is illustrated be constituted of a meander-shaped, strip-shaped conductor 4 having a width significantly smaller than the width of the conductor 3.
• the inductive element is connected serially in the conductor path near the connection thereof to associated receiving and/or transmitting equipment, not shown, by the fact that the conductor path 3 is interrupted there and continues into the narrower conductor.
• the strip- shaped straight portion 3 a, 3 b of the conductor path 3 can be interrupted in the same way as the single inductive element in Fig. 1 but at another, selected distance from the connection of the conductor path.
• the conductor can, if required, continue into wider, for example rectangular parts 5 which form first electrodes of a capacitor. Otherwise, the ends of the conductor having a constant width can at the interrupt act as the first electrodes in the case where it is suitable depending on the wavelengths for which the antenna is intended.
• rectangular parts also other suitable shapes can be used such as triangular shape, trapezium shape or circular shape.
• the two first electrodes are electrically interconnected by a meander-shaped, strip-shaped conductor 7 having a width significantly smaller than the width of the straight portions 3 a, 3b of the conductor and forms an inductor.
• a conducting plane or area 8 is provided that forms a second electrode of the capacitance and is electrically isolated from the conductor path, the inductor conductor 7 and the first electrodes 5.
• the conducting plane can be arranged on a rectangular flexible part 8' of for example polymer film attached to the bottom surface of the carrier 1 in the case where the main conductor 5 of the antenna is located at the top side of the carrier so that the carrier forms a dielectric of the capacitance.
• the conducting area 8 is arranged on the outer side of the flexible film part which in turn is attached on top of the conducting metal pattern that forms the conductor path, the inductor conductor and the first electrode so that the film part forms a dielectric of the capacitance.
• the film part can be called a ground plane but is not connected to signal ground.
• the capacitive parts and the inductor part together form a filter that can act as an interrupt of the antenna for frequencies above a value determined by the values of the capacitance and the inductance of these parts.
• the antenna can with a good efficiency act for two frequency bands.
• the parallel LC-filter formed can act as a trap by the fact that at the resonance frequency such a parallel LC filter has a very large impedance.
• the trap can be parallel resonant so that a receiver and/or transmitter connected to the antenna only "sees" a short antenna conductor.
• the receiver/transmitter "sees" the total. length of the antenna conductor.
• the active part 3a and 3a + 3b respectively of the antenna conductor 3 can in the usual way for example have a length corresponding to a fourth of the wavelength of the intended frequency band.
• the conductor 3 can at least at one of its sides continue into a coupling part 9 that as illustrated can have a circular shape or have some other shape such as being rectangular.
• the diameter or largest dimension of the coupling part significantly exceeds the width of the main portions 3; 3 a, 3b of the conductor.
• This coupling part can be used for capacitive connection of the antenna as will be described hereinafter, to receiving/transmitting equipment.
• Fig. 2b an antenna is illustrated corresponding to that of Fig. 2a but including a meander-shaped main conductor. This antenna can be made shorter then the antenna having a straight main conductor but it can obtain a somewhat lower efficiency.
• the antennas illustrated in Figs. 2a and 2b are intended for receiving in two bands.
• An antenna intended for receiving in three frequency band is illustrated in Fig. 3, mounted on a pane such as a windshield in a motor vehicle.
• the carrying element 1 can include adhesive tape, compare also Fig. 6, attached to one of its surfaces, be provided with a pressure sensitive adhesive corresponding to that provided on the adhesive tape on the same surface or be provided with some other attachment means, see Fig. 6, such as a thread or loop for for example attaching it to a window pane or hanging it an a suitable place respectively, for example in a tree.
• the antenna can be temporarily mounted on a windowpane in some suitable room, for example in a car, a bus, a train or a summer or weekend cottage. Obviously, it can also be perma- nently glued to such a window pane if preferred.
• the com ection of the antenna to a transmitter/receiver is made using a cable 11, see Figs. 4 and 5, which at one of its ends includes a standard connector, not shown, for connection to some radio equipment such as a transmitter/receiver/mobile telephone, compare Fig. 7, and at the other one of its ends has a connector 13.
• the connector includes a capacitor plate 15 that is con- nected to the electric conductor 17 of the cable and can have a design or a shape corresponding to the shape of the coupling part 9 of the antenna conductor or have some other suitable shape and size.
• the connector 13 includes in a first embodiment a suction cup 19 for retaining the connector at the antenna.
• this capacitor When the antenna is mounted to the antenna carrier 1 with a capacitor plate 15 opposite the coupling part of the antenna conductor a capacitor is formed, this providing a capacitive coupling between the antenna conductor and the cable conductor. For a suitable dimensioning this capacitor obtains a suitable small capacitance, so that high frequency signals can continue between the antenna conductor and the cable conductor.
• the size of the plates in this capacitor can for example be designed considering the intermediate material, such as a glass plate in the case where the antenna is permanently mounted to the inner surface of a pane in a multipane window in order to obtain a suitable capacitance of the capacitor formed.
• the connector 13 can include one or more permanent magnets 21 such as an annular magnet.
• the magnets can for attaching the connector to the antenna cooperate with one or more parts 23 of soft magnetic material, for example of thin iron plate, that are attached to the substrate 1 of the antenna close to the coupling part 9.
• the parts 23 can for example include an annular plate that surrounds, as seen in direction towards the large surfaces of the antenna substrate, the coupling part of the antenna conductor.
• the antenna can be easily transported due to its strip-shape.
• the substrate or carrier 1 can as is illustrated in Fig. 6 be designed to include a central longitudinal folding line 25 so that the carrier thereby is divided in two parts of substantially equal size. On at least one of these two parts an antenna conductor according to the description above is provided.
• the carrier can be folded together so that the antenna conductor 3 is protected.
• a person can for example carry the antenna in his bag or pocket or have it placed in a book as a bookmark without risking damage to the antenna.
• the carrier can be provided with pressure sensitive adhesive material 27 so that the antenna with a folded-out carrier can be temporarily mounted to for example an window pane, see Fig. 7.
• the pressure sensitive adhesive material only has to be arranged within limited areas of the carrier 1, e.g. as is shown within rectangular fields at edges of the carrier.
• the antenna can also be made as a dipole, such as is illustrated in Figs. 8 and 9. Then, there are on the same substrate 1 two symmetrically placed and similar configured antenna conductors 3', 3" that each one can be designed according the description of the above and that in the usual way are located along the same line, opposite each other, having the coupling parts 9 located close to each other but not in a direct electric connection with each other. In each antenna branch one or more LC-combinations according to the description above can be provided to make the antenna suitable for plural frequency bands.
• the connection of the antenna can as is illustrated in Fig.
• the cable connector can as has been described above be designed to include a suction cup or magnets but in the embodiment illustrated in Fig. 8 it includes a rectangular part 29 of flexible polymer film, on one surface of which electrically conducting areas 31 are provided, which as is illustrated for example can have a square shape and together with the coupling parts 9 of the antenna conductors form capacitors according to the description above.
• the polymer part 29 can be glued to the antenna substrate 1.
• the connection of the electrically conducting plates 31 for the feeding cable 11' can be accomplished by soldering, see the soldering terminals 33.
• a flexible transmission line 35 of microstrip or stripline type can be used, see Fig. 9.
• This line includes two parallel conductors 37 arranged at or in a flexible carrier and it can be provided if desired, in order to give better transmission characteristics, with one or two ground planes, not shown, arranged close to the conductors.
• the conductors instead being enlarged to form capacitor plates 31 designed in the same way as for the connection using a round feeding cable according to Fig. 8.
• the end of the transmission line including the capacitor plates is in a suitable way at- tached to the intended position at the antenna carrier 1, for example by adhesive bonding, so that capacitors are formed for coupling high frequencies.
• a flexible transmission line of this type but including only one conductor can be used for the simple antennas according to Figs. 1 - 7.
• the dipole antenna can also be connected using a connector including a suction cup or a magnet/magnets such as is illustrated in Figs. 10a and 10b.
• the connection areas 9' of the antenna are designed to have a generally triangular shape, for example such as circular sectors having an angle in the range of 45 - 90°, see Fig. 10a. They cooperate with conducting areas 31' in the connector having a shape similar to that of the coupling areas of the conductor, see Fig. 10b.
• the conducting areas of the connector are arranged inside a suction, cup 19 or in a housing including magnets, such as in Fig. 8 or 9 respectively.
• the coupling areas 9 for the antenna conductors are illustrated to have a circular shape and cooperate with opposite plates 31 also having a circular shape and connected to the antenna cable 11.
• the magnets 21' are here illustrated to be placed directly at the plates 31 and they can then also have a circular shape. They cooperate with plates of steel plate, not shown, mounted directly underneath the coupling areas 9'. Alternatively, these plates can themselves directly constitute the coupling areas but it requires a more complicated connection of the antenna conductors.
• the connector housing 39 can further accommodate an electronic device 41 such as a switch, antenna amplifier or trans- former connected between the cable 11 and the capacitor plates 31 in the housing.
• the antennas described above can in addition to being mounted to a foldable substrate of the type illustrated in Figs. 6 and 7 also be mounted to or in flexible, adhesive tape 41, i.e. a flexible strip provided with a pressure sensitive adhesive, such as is illustrated in Fig. 12b.
• a multitude of antennas can be arranged on one adhesive tape which is delivered to a user formed as a strip rolled up to form a coil 43, see Fig. 12a.
• the coil can be placed in a usual tape holder 45 from which an antenna can be pulled out and cut off to then be mounted at a suitable place.
• the transmission line 37 between the antenna and electronic device can be made on a flexible strip 35', such as is illustrated in Figs. 12c and 13a - 13c. Then, a number of lengths of transmission lines can initially be arranged on the same strip which is wound to form a coil from which a transmission line length can be severed. The coil can be placed in a conventional tape holder 45'.
• the area at the connection place of the transmission line or the antenna can be provided with a pressure sensitive adhesive, not shown, if required.
• the pressure sensitive adhesive of the antenna strip can be used by the method that in mounting the antenna to a surface, first the transmission line is held in contact with the surface on a suitable place and then the antenna strip is placed over the coupling position of the transmission line and is attached thereto and then to the surface in regions of the antenna strip located at the sides of the coupling position.
• the electrically conducting areas of the capacitive coupling on the strip of a dipole antenna and the strip for the transmission line can in this case be designed as illustrated in Figs. 12b, 12c and 13a - 13c, so that no special or separate part has to be soldered to or in some other way be electrically connected to the transmission line.
• the strip of the transmission line can also be designed so that it is not given a too large width.
• the two capacitive coupling areas 9' of the dipole antenna are placed transversely at the sides of each other, taken in the longitudinal direction of the antenna.
• the coupling areas are thus located on the same line perpendicular to the longitudinal direction of the antenna and have a suitable shape, e.g. as illustrated a rectangular shape including possibly rounded corners.
• the coupling areas 47 of the transmission line 37 can have substantially the same shape as the coupling areas of the dipole antenna and are located after or at a distance of each other in the longitudinal direction of the transmission line.
• Fig. 13a also a dipole antenna including meander-shaped main conductors 49 is illustrated.
• Figs. 13b and 13c a dipole antenna designed for two frequency bands is illustrated.
• An antenna and/or a feeding line for an antenna can be designed, when including strip- shaped conductors according the description above, as a logotype or stylized picture. E.g. a logotype such as a trademark can be formed from one or two words or a company name can be used.
• the antenna can be designed as a microstrip, Figs. 14a and 14b, or as a slot, see Fig. 14c,
• Fig. 14d it is illustrated how a dipole antenna is formed by interconnecting the letters of a trademark on both sides of a coupling position to two antenna main con- ductors. In Fig. 14b all letters of the same trademark has been interconnected to form a main conductor of a monopole antenna.
• Figs. 14c and 14d is illustrated how the antenna conductor in a monopole antenna is designed as an elongated field having a constant width with portions removed therefrom or including depressed/elevated portions respectively which form the same trademark.
• the width and the length of the microstrip portions in the embodiment according to Figs. 14a and 14b or of the removed portions or the depressed/elevated portion according to Figs. 14c and 14d respectively are selected considering the wavelength for which the antenna is intended.
• the antenna described above including a strip-shaped main conductor can also be arranged on a substrate or base that to some extent is stiff or rigid, for example or polymer card of the common credit card or paying card format according to Figs. 15a - 15c.
• the substrate 51 can have a rectangular shape and in order to mount it to a smooth surface it can have a pressed or stamped part 53 including a shallow or low bell or cup shape projecting from one side from the base to form a suction cup.
• the antenna main conductor is suitably arranged on the same side of the substrate and can for example over the major portion of its length be located along the periphery of the substrate.
• a monopole antenna is illustrated and in Fig. 15b a dipole antenna for two frequency bands is illustrated.
• a more complicated antenna structure including a strip-shaped main conductor can be designed such as is illustrated in Figs. 16a and 16b.
• the central electrode extends over the surface of the substrate from a distant free end to an inner free end at which it continues into a transmission line part 57 that at its other end has a capacitive coupling area 59 according to the description above.
• the transmission line part is shielded by upper and lower metal layers 61, 63 that are electrically isolated from the transmission part to give the transmission line part a suitable impedance and that are folded around or back about dielectric layers 65, 67 over a length also corresponding to a fourth of the wave length.
• a surrounding area 69 of steel plate is provided and a concentric area 71 located inside this area and also made from steel plate. They are used for the mechanical coupling to a transmission cable, not shown, using magnetic forces according to the description above.
• Such a transmission cable has electric coupling areas of a shape corresponding to the shape of the coupling areas 69 and 71.
• the LC-circuits or LC-filters described above can be designed in a simple way by only using one conductor part having a suitable inductance that in the same time works as an "invisible capacitor".
• the parasite capacitance of the inductor part is thus used.
• the width/length of the inductor part a desired value of the product LC can be obtained.
• a desired resonance frequency or phase shift or impedance can thus be obtained.
• Fig. 17a the parasite capacitances for different shapes of the inductor conductor 44 are illustrated.
• the conductor can be designed as two inductor conductors connected in parallel, e.g. on both sides the main conductor.
• To make the value of the inductance larger two inductor conductors connected in series can be used, which e.g. are placed on both sides of the main conductor.
• FIG. 17a - 17c different embodiment of simple inductor conductors located on one side of the main conductor are illustrated, at b inductors connected in series on both sides and at c inductors connected in parallel on both sides are illustrated.

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Cited By (7)

Citations (11)

• 2003
  • 2003-01-28 SE SE0300206A patent/SE0300206L/sv not_active Application Discontinuation
  • 2003-03-17 WO PCT/SE2003/000447 patent/WO2003079487A1/en not_active Application Discontinuation
  • 2003-03-17 AU AU2003212773A patent/AU2003212773A1/en not_active Abandoned

Patent Citations (11)

Non-Patent Citations (2)

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