GB2470113A - Magnetic core and conductive plate arrangement for a magnetic antenna - Google Patents

Magnetic core and conductive plate arrangement for a magnetic antenna Download PDF

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Publication number
GB2470113A
GB2470113A GB1007345A GB201007345A GB2470113A GB 2470113 A GB2470113 A GB 2470113A GB 1007345 A GB1007345 A GB 1007345A GB 201007345 A GB201007345 A GB 201007345A GB 2470113 A GB2470113 A GB 2470113A
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United Kingdom
Prior art keywords
magnetic
antenna
conductor
magnetic core
coil
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Granted
Application number
GB1007345A
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GB201007345D0 (en
GB2470113B (en
Inventor
Hiromitsu Ito
Hiroyuki Kubo
Kuniaki Yosui
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Murata Manufacturing Co Ltd
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Murata Manufacturing Co Ltd
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Publication of GB201007345D0 publication Critical patent/GB201007345D0/en
Publication of GB2470113A publication Critical patent/GB2470113A/en
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Publication of GB2470113B publication Critical patent/GB2470113B/en
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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
    • G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
    • G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
    • G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
    • G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
    • G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
    • 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
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • 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
    • H01Q1/2208—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems
    • H01Q1/2225—Supports; Mounting means by structural association with other equipment or articles associated with components used in interrogation type services, i.e. in systems for information exchange between an interrogator/reader and a tag/transponder, e.g. in Radio Frequency Identification [RFID] systems used in active tags, i.e. provided with its own power source or in passive tags, i.e. deriving power from RF signal
    • 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
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/06—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop with core of ferromagnetic material

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Details Of Aerials (AREA)
  • Coils Or Transformers For Communication (AREA)

Abstract

An antenna device comprises a magnetic antenna 51 including a flexible substrate 10 with a spiral conductive coil 12 formed on a base 11. A magnetic core 20 is disposed on or close to the substrate 10 and a conductor plate 40 is disposed close to the magnetic antenna 51 and the magnetic core 20 is disposed so as not to cover a portion A3 of the coil conductor 12. The magnetic core 20 is located adjacent a first edge S1 of the conductor plate 40 with a length and width such that it covers the central opening CW of the coil 12 and at least a portion of the coil 12 in region A2. The core 20 may also cover one or more portions of regions Al. The coil 12 and core 20 may be located at a certain position and arranged at certain distances relative to the four edges of the conductive plate 40. The coil region A3, which is not covered by the magnetic core 20, may be located at a distance approximately equal to or greater than 0.4 times the length of the conductive plate 40 from the second edge S2. The antenna device aims to be capable of being strongly magnetically coupled with an antenna of a communication partner whilst having a high communication performance.

Description

ANTENNA DEVICE
[Technical Field]
[00011 The present invention relates to antenna devices used in, for example, RFID (Radio Frequency Identification) systems that communicate with external devices via electromagnetic signals.
[Background Art]
[0002] In RFID systems, which are being increasingly used these days, antennas for information communication are installed in both portable electronic devices such as cellular phones and readers/writers so that data is communicated therebetween. Such antenna devices for the RFID include magnetic antennas including magnetic cores disclosed in Japanese unexamined Patent Application Publication No. 2002-298095; 2002-208814 and 2005-210223 (1 to 3) [0003] Structures of portable electronic devices including the antennas described in Patent Documents 1 to 3 will now be described with reference to the drawings.
Fig. 1 includes three orthographic views illustrating a portable electronic device including the antenna described in Patent Document 1 incorporated therein. A magnetic
S
antenna 31 includes a flexible substrate 10 formed of a base 11 and a spiral-shaped coil conductor 12 formed thereon and a magnetic core 20 provided for the flexible substrate 10, the magnetic core being a sheet or a flat plate having a shape similar to that of the coil conductor 11.
[0004] The antenna described in Patent Document 2 includes a coil conductor formed so as to have a concentric shape and a magnetic sheet with high permeability disposed so as to extend from the intermediate portion between the center of diameter of the coil conductor arid the inner periphery of the coil conductor, where magnetic fluxes are generated, to outside the coil conductor.
[0005] Fig. 3 includes two orthographic views illustrating a portable electronic device including the magnetic antenna described in Patent Document 2 incorporated therein, the shape of the antenna being changed toa rectangle. A magnetic antenna 32 includes a flexible substrate 10 formed of a base 11 and a spiral-shaped coil conductor 12 formed thereon and a magnetic core 20 disposed on the flexible substrate 10, the magnetic core extending from the intermediate portion between the center of the coil conductor 12 and the inner periphery of the coil conductor 12 to outside the coil conductor 12.
[0006] The antenna described in Patent Document 3 includes a magnetic core only at a position inside a loop-shaped coil conductor.
Fig. 4 includes two orthographic views illustrating a portable electronic device including the magnetic antenna described in Patent Document 3 incorporated therein, the shape of the antenna being changed to a rectangle. A magnetic antenna 33 includes a flexible substrate 10 formed of a base 11 and a spiral-shaped coil conductor 12 formed thereon and a magnetic core 20 disposed on the flexible substrate 10, the magnetic core being disposed inside the inner periphery of the coil conductor 12.
[Prior Art Document]
[Patent Document] [0007]
Summary of the Invention
[0008] In the antenna shown in Fig. 1, the self-inductance of the coil conductor is larger than the mutual inductance between the coil conductor and a coil conductor serving as a communication partner. That is, since the proportion of the magnetic fluxes that are not magnetically coupled with the antenna of the communication partner (a reader/writer, an IC card, or a mobile terminal with an IC card function, for example) is large, the coupling is weak, resulting in a poor communication performance.
[00091 Moreover, since the loss in the magnetic energy in the magnetic core is large, the communication performance is degraded. That is, as shown in Fig. 1, when a conductor plate 40 such as a substrate of a mobile terminal exists at the rear of the coil conductor 12, a part of a magnetic field generated by the antenna of the communication partner flows through paths shown by magnetic fluxes MFa in Fig. 1.
These magnetic fluxes MFa negligibly contribute to the coupling between the antennas since the magnetic fluxes do not Interlink with the loop of the coil conductor 12.
[00101 Moreover, the self-Inductance of the coil conductor has an upper limit since a resonance circuit formed by a combination of the magnetic antenna 31 and a capacitor (not shown) resonates at a predetermined frequency. Therefore, it is not preferable that the self-inductance be increased by the magnetic fluxes that pass through or, so to speak, take shortcuts through the magnetic core while negligibly contributing to the coupling at the coilconductor.
Furthermore, energy is lost in the magnetic core 20 when the magnetic fluxes flow therethrough. In particular, more energy is lost in a portion where the magnetic flux density is high (portion where the conductor and the magnetic core are close to each other). Figs. 2(A) to 2(C) are three orthographic views illustrating the loss in the magnetic energy. As shown in Figs. 2(A) to 2(C), a large loss occurs at a hatched portion shown in Fig. 2(C) due to magnetic fluxes MFd that take shortcuts through the magnetic core 20 without interlinking with the magnetic fluxes of the antenna of the communication partner.
[00111 In the antenna shown in Fig. 3, there are problems in that magnetic fluxes do not easily pass through portions Al of the coil conductor shown in Fig. 3, through which the magnetic fluxes could pass, since no magnetic body exists at the portions Al, and that the magnetic fluxes do not easily enter the portions Al since the proportion of the magnetic body at the opening areas is small.
[0012] In the antenna shown in Fig. 4, there are also problems in that magnetic fluxes do not easily pass through portions Al and A2 of the coil conductor shown in Fig. 4, through which the magnetic fluxes could pass,, since no magnetic body exists at the portions Al and A2, and that the magnetic fluxes do not easily enter the portions Al and A2 since the proportion of the magnetic body at the opening areas is small.
[0013] Therefore, the present invention aims to provide an antenna device capable of being strongly magnetically coupled with an antenna of a communication partner and having a high communication performance.
[0014] The above-described problems maybe addressed by, an antenna device of the present invention which has the following structure.
An antenna device includes a magnetic antenna, including a flexible substrate on which a coil conductor is formed and a magnetic core disposed on or close to the flexible substrate, and a conductor plate disposed close to the magnetic antenna. The coil conductor has a spiral shape having a winding center as a conductor opening portion, and the magnetic core is disposed adjacent to a first side end of the conductor plate so as not to cover a portion of the coil conductor, the portion being located at a position furthest from the first side end.
[0015] For example, the magnetic core can be disposed so as not to cover a conductor portion located at a position separated from a second side end of the conductor plate facing the first side end by a distance more than or equal to about 0.4 times the length of the conductor plate.
According to this structure, magnetic coupling with an antenna of a communication partner may be enhanced, and communication performance may be improved. Moreover, loss in magnetic energy in the magnetic core may be reduced, and communication performance may be improved. Furthermore, the size of the magnetic core may be reduced.
[00161 Moreover, the magnetic core does not cover a portion of the coil conductor adjacent to eitheror both of third and fourth side ends of the conductor plate orthogonal to the first and second side ends.
According to this structure, the inductance can be changed with substantially no degradation in communication performance. Moreover, the size of the magnetic core may be reduced.
[0017] According to embodiments of the present invention, the proportion of magnetic fluxes that are magnetically coupled with an antenna of a communication partner is increased, and communication performance is improved. Moreover, loss in magnetic energy in the magnetic core is reduced, and communication performance is improved.
[Brief Description of the Drawings]
The invention will now be described by way of example only with reference to the accompanying drawings in which: [0018] [Fig. 1] Fig. 1 includes three orthographic views illustrating a portable electronic device including an antenna described in Patent Document 1 incorporated therein.
[Fig. 21 Figs. 2(A) to 2(C) are three orthographic views illustrating loss in magnetic energy in the antenna device shown in Fig. 1.
[Fig. 3] Fig. 3 includes two orthographic views illustrating a portable electronic device including a magnetic antenna described in Patent Document 2 incorporated therein, the shape of the antenna being changed to a rectangle.
[Fig. 4] Fig. 4 includes two orthographic views illustrating a portable electronic: device including a magnetic antenna described in Patent Document 3 incorporated therein, the shape of the antenna being changed to a rectangle.
[Fig. 5] Fig. 5 includes three orthographic views of an antenna device according to a first embodiment.
[Fig. 61 Fig. 6 illustrates:the relationship between the position of a magnetic antenna 51 with respect to a conductor plate 40 shown in Fig. 5 and the amount of coupling with an antenna of a communication partner.
[Fig. 7] Fig. 7(A) is a top view of a magnetic antenna 52 used in an antenna device according to a second embodiment.
Fig. 7(B) is a bottom view thereof.
[Fig. 81 Figs. 8(A) and 8(B) illustrate the structure of another magnetic antenna 53 used in the antenna device according to the second embodiment. Fig. 8(A) is a top view and Fig. 8(B) is a bottom view of the magnetic antenna 53.
[Fig. 91 Fig. 9 includes three orthographic views illustrating the relationship between the width X of the conductor plate 40 in a lateral direction thereof and the distance x from a third side end S3 or a fourth side end S4 to a coil conductor 12 of the magnetic antenna 53.
[Fig. 101 Fig. 10 illustrates the relationship between x/X and the amount of coupling and the relationship between x/X and the inductance of the magnetic antenna 53.
[Fig. 11] Fig. 11 illustrates the definition of portions Al of the coil conductor adjacent to the third and fourth side ends of the conductor plate 40 orthogonal to first and second side ends.
[Fig. 12] Figs. 12(A) and 12(B) illustrate the structure of a magnetic antenna 54 used in an antenna device according to a third embodiment. Fig. 12(A) is a top view and Fig. 12(B) is a bottom view of the magnetic antenna 54.
[Fig. 13] Figs. 13(A) and 13(B) illustrate the structure of another magnetic antenna 55 used in the antenna device according to the third erribodirnent. Fig. 13(A) is a top view and Fig. 13(B) is a bottom view of the magnetic antenna 55.
Detailed Description of Embodiments of the Invention [00191 [First Embodiment] Fig. 5 includes three orthographic views of an antenna device according to a first embodiment. This antenna device includes a magnetic antenna 51 and a conductor plate 40.
The magnetic antenna 51 includes a flexible substrate 10 and a magnetic core 20. The flexible substrate 10 includes a base 11 and a spiral-shaped coil conductor 12 formed thereon, a winding center of the coil being located as a conductor opening portion CW.
[00201 The length L (length in a longitudinal direction of the conductor plate 40) of the magnetic core 20 is smaller than that of the flexible substrate 10. The magnetic core 20 is located adjacent to a first side end Si of the conductor plate 40 and so as not to cover a portion P3 of the coil conductor, the portion A3 being the furthest from the first side end Si. This structure produces the following effects.
[0021] Unlike the antenna device shown in Figs. 2(A) to 2(C), energy loss in the magnetic core 20 through which magnetic fluxes take shortcuts is reduced, and the efficiency of the antenna is improved.
Moreover, unlike the antenna device shown in Fig. 3, -10 -magnetic coupling between the antenna of the antenna device and the antenna of the communication partner is enhanced since the magnetic core 20 exists at portions Al of the coil conductor, magnetic fluxes attempting to pass through the portions Al.
[0022] Furthermore, magnetic fluxes can pass through the conductor opening portion CW of the magnetic antenna 51 more easily compared with the case of the antenna device having the structure shown in Fig. 4 since the magnetic core 20 exists at a portion A2 of the coil conductor, the portion A2 being adjacent to the first side end Sl of the conductor plate 40. This leads to an improvement in the characteristics of the antenna.
[00231 Fig. 6 illustrates the relationship between the position of the magnetic antenna 51 with respect to the conductor plate 40 shown in Fig. 5 and the amount of coupling with an antenna of a communication partner. Herein, Y denotes the length of the conductor plate 40 shown in Fig. in the longitudinal direction thereof, and y denotes the distance from a second side end S2 of the conductor plate 40 facing the first side end Si to the portion A3 of the coil conductor.
[0024] -11 -In Fig. 6, the abscissa represents the ratio of the length y to the length Y, and the ordinate represents the amount of coupling with the antenna of the communication partner. In Fig. 6, a broken line A indicates the characteristic of a structure in which the magnetic core 20 shown in Fig. 5 extends to the portion A3 of the coil conductor (structure in which the magnetic core 20 extends over the entire area of the coil conductor 12), and a broken line B indicates the characteristic of the antenna device having the structure shown in Fig. 5.
[00251 In a range where y is small (y/Y < 0.4), the amount of coupling is larger when the magnetic core 20 extends over the entire area of the coil conductor 12.
[00261 However, in a range of y/Y �= 0.4, a stronger coupling can be obtained with the structure inwhich the magnetic core 20 does riot exist at the portion A3 of the coil conductor adjacent to the second side end S2 of the conductor plate 40 as shown in Fig. 5.
[00271 Therefore, when the magnetic antenna 51 is disposed at a position adjacent to either side end, it is preferable that the magnetic antenna be disposed.adjacent to the first side end Si of the conductor plate 40 as shown in Fig. 5 and -12 -that the magnetic core 20 should not cover the portion A3 of the coil conductor, the portion A3 beingthe furthest from the first side end Si.
[00281 [Second Embodiment] In the first embodiment, the position of the magnetic core 20 with respect to the flexible substrate 10 in the longitudinal direction of the conductor plate 40 was described. In a second embodiment, the shape of a portion of a magnetic core 20 adjacent to a third or fourth side end of a conductor plate 40 orthogonal to first and second side ends formed by using an phenomenon similar to that described above will be described.
[0029] Fig. 7(A) is a top view of a magnetic antenna 52 used in an antenna device according to the second embodiment.
Fig. 7(B) is a bottom view thereof.
The magnetic antenna 52 includes a flexible substrate and the magnetic core 20. The flexible substrate 10 includes a rectangular base ii and a spiral-shaped coil conductor 12 formed thereon, a winding center of the coil being located as a conductor opening portion CW.
[0030] Although only the magnetic antenna 52 is illustrated in Figs. 7(A) and 7(B), the magnetic antenna 52 is replaced -13 -
S
with the magnetic antenna 51 shown in Fig. 5 in the first embodiment. That is, the magnetic antenna 52 is disposed adjacent to a side end of the conductor plate 40 as is the antenna device shown in Fig. 5. Iii the example shown in Figs. 7(A) and 7(B), the magnetic core 20 is formed so as not to cover a portion Al of the coil conductor adjacent to the third side end of the conductor plate 40 orthogonal to the first and second side ends in addition to a portion A3 of the coil conductor, the portion A3 being the furthest from the first side end Si of the conductor plate 40.
[0031] Figs. 8(A) and 8(B) illustrate the structure of another magnetic antenna 53 used in the antenna device according to the second embodiment. Fig. 8(A) is a top view and Fig. 8(B) is a bottom view of the magneticantenna 53. This magnetic antenna 53 is disposed adjacent to a side end of the conductor plate 40 as is the antenna device shown in Fig. 5.
[0032] The magnetic core 20 of the magnetic antenna 53 shown in Figs. 8(A) and 8(B) is formed so as not to cover the portions Al of the coil conductor adjacent to the third and fourth side ends of the conductor plate 40 orthogonal to the first and second side ends in addition to the portion A3 of the coil conductor, the portion A3 being the furthest from -14 -the first side end Si of the conductor plate 40.
[00331 Fig. 9 includes three orthographic views illustrating the relationship between the width X of the conductor plate in a lateral direction thereof and the distance x from the third side end S3 or the fourth side end S4 to the coil conductor 12 of the magnetic antenna 53.
Moreover, Fig. 10 illustrates the relationship between x/X and the amount of coupling and the relationship between x/X and the inductance of the magnetic antenna 53. Herein, broken lines A indicate the characteristics when the magnetic core 20 of the magnetic antenna 53 shown in Fig. 9 covers the portions Al of the coil conductor, and broken lines B indicate the characteristics when the antenna device 53 shown in Figs. 8(A) to 9 is used.
[00341 As is clear from Fig. 10, changes of the characteristic shown by the broken line B in the amount of coupling with respect to changes in x/X are reduced compared with changes of the characteristic shown by the broken line A while changes in the inductance with respect to changes in x/X are substantially the same.. Therefore, the inductance can be easily set with, substantially no degradation in communication performance.
[00351 -15 -Herein, the portions Al of the coil conductor adjacent to the third and fourth side ends of the conductor plate 40 orthogonal to the first and second side ends can also be defined as follows.
When farness" from the side ends of the conductor plate 40 is defined by xl/X, x2/X, yi/Y, and y2/Y, where xl, x2, yl, and y2 are distances from each side end of the conductor plate 40 to the coil conductor 12 and X and Y are lengths of the sides facing each other as shown in Fig. 11, the portions Al of the coil conductor are the second and third furthest conductor portions.
The magnetic core can be formed so as not to cover either or both of the second and third furthest conductor portions.
[00361 [Third Embodiment] Figs. 12(A) and 12(B) illustrate the structure of a magnetic antenna 54 used in an antenna device according to a third embodiment. Fig. 12(A) is a top view and Fig. 12(B) is a bottom view of the magnetic antenna 54. This magnetic antenna 54 is disposed adjacent to a side end of a conductor plate 40 as is the antenna device shown in Fig. 5.
[00371 This magnetic antenna differs from the magnetic antenna 52 shown in Figs. 7(A) and 7(B) in the second embodiment as -16 -to the shape of a magnetic core 20. The magnetic core 20 of the magnetic antenna 54 shown in Figs. 12(A) and 12(B) is formed so as not to cover a part of a portion Al of a coil conductor adjacent to a side end orthogonal to a first side end Si arid a second side end S2 of the conductor plate 40.
[0038] Figs. 13(A) and 13(B) illustrate the structure of another magnetic antenna 55 used in the antenna device according to the third embodiment. Fig. 13(A) is a top view and Fig. 13(B) is a bottom view of the magnetic antenna 55.
This magnetic antenna 55 is disposed adjacent to a side end of the conductor plate 40 as is the antenna device shown in Fig. 5.
[00391 This magnetic antenna differs from the magnetic antenna 52 shown in Figs. 7(A) and 7(R) in the second embodiment as to the shape of the magnetic core 20. The magnetic core 20 of the magnetic antenna 55 shown in Figs. 13(A) and 13(B) is formed so as not to cover parts of the two portions Al of the coil conductor adjacent to the side ends orthogonal to the first side end Si and the second side end S2 of the conductor plate 40.
[0040] When the magnetic core 20 is formed so as not to cover the entire or a part of the portion adjacent to the third or 17 -fourth side end of the conductor plate 40 orthogonal to the first and second side ends in this manner, the inductance can be easily set with substantially no degradation in communication performance as in the second embodiment.
[Reference Numerals] [0041] Al, A2, and A3: portions of a coil conductor CW: conductor opening portion MFa: magnetic fluxes MFd: magnetic fluxes Si: first side end S2: second side end S3: third side end S4: fourth side end 10: flexible substrate 11: base 12: coil conductor 20: magnetic core 31 to 33: known magnetic antennas 40: conductor plate 51 to 55: magnetic antennas -18 -

Claims (4)

  1. ICLAIMS1. An antenna device comprising: a magnetic antenna including a flexible substrate on which a coil conductor is formed and a magnetic core disposed on or close to the flexible substrate; and a conductor plate disposed close to the magnetic antenna, wherein the coil conductor has a spiral shape having a winding center as a conductor opening portion, and the magnetic core is disposed adjacent to a first side end of the conductor plate so as not to cover a portion of the coil conductor, the portion being located at a position furthest from the first side end.
  2. 2. The antenna device according to Claim 1, wherein the magnetic core is disposed so as not to cover a conductor portion located at a position separated from a second side end of the conductor plate facing the first side end by a distance more than or equal to about 0.4 times the length of the conductor plate.
  3. 3. The antenna device according to Claim 1 or 2, wherein the magnetic core does not cover a portion of the coil conductor adjacent to either or both of third and fourth side ends of the conductor plate orthogonal to the first and second side ends.-19 -I
  4. 4. An antenna device substantially as herein described with reference to the accompanying drawings 5 -6, 7 -11 or 12 -13.-20 -
GB1007345A 2009-05-08 2010-04-30 Magnetic core and conductive plate arrangement for a magnetic antenna Active GB2470113B (en)

Applications Claiming Priority (1)

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JP2009113797A JP4978657B2 (en) 2009-05-08 2009-05-08 Antenna device

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GB2470113A true GB2470113A (en) 2010-11-10
GB2470113B GB2470113B (en) 2011-10-19

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US20150288054A1 (en) * 2012-10-17 2015-10-08 Dexerials Corporation Electronic device and antenna device
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CN105576343B (en) * 2016-01-25 2018-04-06 电子科技大学 A kind of near field communication antenna device
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EP1439608A1 (en) * 2001-09-28 2004-07-21 Mitsubishi Materials Corporation ANTENNA COIL AND RFID&minus;USE TAG USING IT&comma; TRANSPONDER&minus;USE ANTENNA
EP1484816A1 (en) * 2002-01-17 2004-12-08 Mitsubishi Materials Corporation Antenna for reader/writer and reader/writer having the antenna

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CN104638342A (en) * 2011-11-09 2015-05-20 株式会社村田制作所 Antenna device and electronic apparatus
CN104638342B (en) * 2011-11-09 2018-02-09 株式会社村田制作所 Antenna assembly and electronic equipment
US9627759B2 (en) 2012-01-10 2017-04-18 Murata Manufacturing Co., Ltd. Antenna device antenna module
US20150288054A1 (en) * 2012-10-17 2015-10-08 Dexerials Corporation Electronic device and antenna device
US10236557B2 (en) * 2012-10-17 2019-03-19 Dexerials Corporation Electronic device and antenna device
DE102013104059A1 (en) * 2013-04-22 2014-10-23 Infineon Technologies Ag Antenna arrangement, communication device and antenna structure
US10096902B2 (en) 2013-04-22 2018-10-09 Infineon Technologies Ag Antenna arrangement, communication appliance and antenna structure
DE102013104059B4 (en) 2013-04-22 2024-05-29 Infineon Technologies Ag Antenna arrangement and communication device

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JP4978657B2 (en) 2012-07-18
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JP2010263486A (en) 2010-11-18
GB2470113B (en) 2011-10-19
CN101882711B (en) 2013-03-13

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