Wireless communication device

Abstract

This wireless communication device includes: a first coil having the number of turns of one turn or more; an RFIC chip including a first terminal connected to one end of the first coil and a second terminal connected to the other end of the first coil; a second coil coupled to the first coil by magnetic field and having the number of turns of one turn or more; and an open antenna connected to the second coil. The first and second coils are disposed adjacent to each other such that the second coil is positioned outside the coil opening of the first coil when viewed in the extending direction of the first winding axis of the first coil, and the first coil is positioned outside the coil opening of the second coil when viewed in the extending direction of the second winding axis of the second coil.

Description

wireless communication devices

[0001] The present disclosure relates to wireless communication devices.

[0002] For example, Patent Document 1 discloses an IC tag (wireless communication device) in which an antenna and an IC chip (RFIC (Radio Frequency Integrated Circuit) chip) are connected via magnetic field coupling. Specifically, a rectangular loop electrode extending from one input / output terminal of the IC chip to the other input / output terminal is magnetically coupled to a linear magnetic field coupling portion of the antenna extending parallel to one side of the loop electrode.

[0003] JP 2010-268023 A

[0004] However, in the case of the IC tag described in Patent Document 1, in order to achieve a sufficient degree of magnetic field coupling, the linear magnetic field coupling portion of the antenna needs to have a certain length, which results in an increase in the size of the entire antenna, which limits the miniaturization of the IC tag.

[0005] Therefore, an object of the present disclosure is to miniaturize a wireless communication device in which an antenna and an RFIC chip are connected via magnetic field coupling while realizing a sufficient degree of magnetic field coupling.

[0006] In order to solve the above technical problems, according to one aspect of the present disclosure, there is provided a wireless communication device comprising: a first coil having one or more turns; an RFIC chip having a first terminal connected to one end of the first coil and a second terminal connected to the other end of the first coil; a second coil having one or more turns and magnetically coupled to the first coil; and an open-type antenna connected to the second coil, wherein the first and second coils are arranged adjacent to each other so that the second coil is located outside a coil opening of the first coil when viewed in the extension direction of a first winding axis of the first coil, and so that the first coil is located outside a coil opening of the second coil when viewed in the extension direction of a second winding axis of the second coil.

[0007] According to the present disclosure, a wireless communication device in which an antenna and an RFIC chip are connected via magnetic field coupling can be miniaturized while achieving a sufficient degree of magnetic field coupling.

[0008] 1 is a perspective view of a wireless communication device according to a first embodiment of the present disclosure; 2 is a top view of a wireless communication device according to the first embodiment; 3 is a diagram showing components provided on a first surface of a sheet member in a wireless communication device according to the first embodiment; 4 is a diagram showing components provided on a second surface of a sheet member in a wireless communication device according to the first embodiment; 5 is a diagram showing the directivity of a wireless communication device of an example; 6 is a diagram showing the directivity of a wireless communication device of a comparative example; 7 is a perspective view of a wireless communication device according to a second embodiment of the present disclosure; 8 is a top view of a wireless communication device according to the second embodiment;

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0010] (First Embodiment) Fig. 1 is a perspective view of a wireless communication device according to a first embodiment of the present disclosure. Fig. 2 is a top view of the wireless communication device according to the first embodiment. Note that the X-Y-Z Cartesian coordinate system shown in the drawings is intended to facilitate understanding of the embodiments of the present disclosure and does not limit the embodiments. The X-axis direction indicates the width direction of the wireless communication device, the Y-axis direction indicates the depth direction, and the Z-axis direction indicates the thickness direction.

[0011] 1 and 2, the wireless communication device 10 according to the first embodiment is a sheet-like device. The wireless communication device 10 according to the first embodiment is a so-called RFID (Radio Frequency Identification) tag, and is attached to an item G when in use.

[0012] 1 and 2, in the first embodiment, a wireless communication device 10 includes a sheet member 12 made of a dielectric material. The sheet member 12 is made of, for example, a polyimide film. The sheet member 12 is rectangular and includes a first surface 12a and a second surface 12b opposite to the first surface 12a.

[0013] Fig. 3 is a diagram showing components provided on a first surface of a sheet member in a wireless communication device according to embodiment 1. Fig. 4 is a diagram showing components provided on a second surface of a sheet member in a wireless communication device according to embodiment 1.

[0014] 1 to 4, in the first embodiment, a sheet member 12 is provided with an RFIC (Radio Frequency Integrated Circuit) chip 14, a first coil 16, a second coil 18, and an antenna 20. Specifically, the RFIC chip 14 and the first coil 16 are provided on a first surface 12a of the sheet member 12. The second coil 18 is provided on a second surface 12b of the sheet member 12. The antenna 20 is provided separately on the first surface 12a and the second surface 12b.

[0015] The RFIC chip 14, details of which will be described later, is configured to perform wireless communication with an external device via the antenna 20. For example, the RFIC chip 14 is a chip that operates at a communication frequency and has a structure in which various elements are built into a semiconductor substrate made of a semiconductor material such as silicon.

[0016] In the present embodiment, the first coil 16 is a planar coil having one or more turns (number of windings), and is a conductor pattern made of a conductive material such as copper or aluminum. In the present embodiment, the number of turns of the first coil 16 is three.

[0017] The outer end 16 a and the inner end 16 b of the first coil 16 are connected to the RFIC chip 14 in a DC manner.

[0018] 3, the RFIC chip 14 includes first and second input / output terminals 14a and 14b for connection to the first coil 16. The outer end 16a of the first coil 16 is joined to the first input / output terminal 14a of the RFIC chip 14 via solder or the like.

[0019] In the first embodiment, the inner end 16b of the first coil 16 is connected to the second input / output terminal 14b of the RFIC chip 14 via a conductor pattern 22 provided on the second surface 12b of the sheet member 12 and a conductor pattern 24 provided on the first surface 12a. Specifically, the inner end 16b of the first coil 16 on the first surface 12a of the sheet member 12 and one end 22a of the conductor pattern 22 on the second surface 12b are connected to each other via an interlayer connection conductor 26, such as a through-hole conductor, that penetrates the sheet member 12. Next, the other end 22b of the conductor pattern 22 on the second surface 12b of the sheet member 12 and one end 24a of the conductor pattern 24 on the first surface 12a are connected to each other via an interlayer connection conductor 28 that penetrates the sheet member 12. The other end 24b of the conductor pattern 24 is joined to the second input / output terminal 14b of the RFIC chip 14 via solder or the like.

[0020] In the present embodiment, the second coil 18 is a planar coil having one or more turns (number of windings), and is a conductor pattern made of a conductive material such as copper or aluminum. In the present embodiment, the number of turns of the second coil 18 is 4.5 turns.

[0021] The outer end 18 a and the inner end 18 b of the second coil 18 are connected to the antenna 20 in a DC manner.

[0022] Specifically, the antenna 20 is an open-type antenna, and in the case of the first embodiment, is a dipole antenna. The antenna 20 is composed of a first radiating portion 30 provided on the first surface 12a of the sheet member 12 and a second radiating portion 32 provided on the second surface 12b. The first and second radiating portions 30, 32 of the antenna 20 are each a conductor pattern made of a conductive material such as copper or aluminum.

[0023] Furthermore, the first and second radiating portions 30, 32 of the antenna 20 are spaced apart when viewed in the thickness direction (Z-axis direction) of the wireless communication device 10. A second coil 18 is disposed between the first radiating portion 30 and the second radiating portion 32. An outer end 18a of the second coil 18 is connected to a base end 30a of the first radiating portion 30. In the first embodiment, the second coil 18 and the first radiating portion 30 are different portions of the same conductor pattern. An inner end 18b of the second coil 18 is connected to a base end 32a of the second radiating portion 32 provided on the first surface 12a of the sheet member 12 via an interlayer connection conductor 34 that penetrates the sheet member 12.

[0024] 2 , in the antenna 20, the first and second radiating portions 30, 32 and the second coil 18 are aligned diagonally across the rectangular sheet member 12 when viewed in the thickness direction (Z-axis direction). Specifically, the first radiating portion 30 extends diagonally from the second coil 18 toward the corner portion 12c of the sheet member 12, and the second radiating portion 32 extends diagonally from the second coil 18 toward the corner portion 12d opposite the corner portion 12c. That is, the open ends 30b, 32b of the first and second radiating portions 30, 32 are disposed at the corner portions 12c, 12d of the sheet member 12. Furthermore, the portions between the base ends 30a, 32a and the open ends 30b, 32b of the first and second radiating portions 30, 32, respectively, extend in a meandering pattern. Due to the arrangement and shape of the first and second radiating sections 30, 32 of the antenna 20, the sheet member 12 is made smaller, i.e., the wireless communication device 10 is made smaller, while the antenna 20 has a predetermined antenna length (compared to, for example, when the antenna 20 is linear and extends in the width direction (X-axis direction) or depth direction (Y-axis direction) of the sheet member 12).

[0025] In such a wireless communication device 10, when the open antenna 20 receives a signal (radio wave) from an external device (e.g., a reader / writer device), a current corresponding to the received signal flows from the antenna 20 to the second coil 18. The second coil 18, through which the current flows, generates a magnetic field corresponding to the received signal. This magnetic field causes a current corresponding to the received signal to flow in the first coil 16. The current from the first coil 16 drives the RFIC chip 14. The driven RFIC chip 14 outputs a response signal (current) corresponding to information (data) stored therein to the first coil 16. The first coil 16, through which the current flows, generates a magnetic field corresponding to the response signal. In response to this magnetic field, a current corresponding to the response signal flows in the second coil 18, and this current is supplied to the antenna 20. The antenna 20 then emits radio waves corresponding to the response signal.

[0026] As described above, the operation of the wireless communication device 10 is made possible by the mutual magnetic field coupling between the first coil 16 and the second coil 18. Furthermore, this magnetic field coupling between the coils improves the directivity of the wireless communication device 10. Note that "improved directivity" here refers to a state in which there is little variation in the communication distance in various directions.

[0027] Fig. 5 is a diagram showing the directivity of the wireless communication device of the example, and Fig. 6 is a diagram showing the directivity of the wireless communication device of the comparative example.

[0028] 5 and 6 show the directivity of the wireless communication device 10 of the example according to the first embodiment and the wireless communication device of the comparative example. Specifically, the directivity is shown by a line Wxz indicating the electromagnetic field strength of the radio wave radiated from the origin O on the X-Z plane, and a line Wyz indicating the electromagnetic field strength of the radio wave radiated from the origin O on the Y-Z plane. Since the wireless communication device is placed at the origin O, the linear distance and direction from the origin O to the line represent the communication performance of the wireless communication device.

[0029] The wireless communication device of the comparative example has a configuration in which the second coil 18 is removed from the wireless communication device 10 according to the first embodiment, i.e., the first radiating portion 30 and the second radiating portion 32 of the antenna 20 are connected via a linear conductor pattern. In the comparative example, this linear conductor pattern and the first coil 16 are magnetically coupled.

[0030] 5 and 6, in both the Example and the Comparative Example, the communication distance in the antenna extension direction (X-axis direction) is shorter than in other directions. However, when comparing the Example and the Comparative Example, the communication distance in the antenna extension direction of the Example is longer than that of the Comparative Example. This is because the antenna 20 is connected to the second coil 18, and the second coil 18 is magnetically coupled with the first coil 16 with a sufficient degree of magnetic coupling.

[0031] It should be noted that a wireless communication device of the comparative example that does not include the second coil 18 can also achieve the same performance as the wireless communication device 10 of the embodiment. However, to achieve this, it is necessary to increase the size of the first coil 16 and connect the first radiating portion 30 and the second radiating portion 32 and extend the linear conductor pattern that magnetically couples with the first coil 16. In other words, the wireless communication device of the comparative example must be increased in size to achieve the same performance as the embodiment. In other words, the wireless communication device 10 of the embodiment is miniaturized by connecting the antenna 20 to the second coil 18 and magnetically coupling the second coil 18 to the first coil 16.

[0032] As described above, the directivity of the wireless communication device 10 depends on the degree of magnetic field coupling between the first coil 16 and the second coil 18. Therefore, the wireless communication device 10 according to the first embodiment is configured so that the first coil 16 and the second coil 18 are magnetically coupled with a sufficient degree of magnetic field coupling. The features for this will now be described.

[0033] 2 and as described above, the first and second coils 16, 18 are provided on the first and second surfaces 12a, 12b, respectively, of the sheet member 12. Therefore, the first and second coils 16, 18 are planar, and their respective winding axes (first and second winding axes) C1, C2 are substantially parallel to the thickness direction (Z-axis direction) of the sheet member 12. As a result, the first winding axis C1 of the first coil 16 and the second winding axis C2 of the second coil 18 are substantially parallel to each other.

[0034] Furthermore, the first and second coils 16, 18 each have a coil opening 16c, 18c that opens in the direction in which the first and second winding axes C1, C2 extend (the Z-axis direction). The "coil opening" here refers to the area surrounded by the inner edge of the innermost turn of conductor in the coil when viewed in the direction in which the coil's winding axis extends. The magnetic flux of the magnetic field generated by the coil passes through the coil opening. In the first embodiment, a portion of the magnetic flux generated by one of the first and second coils 16, 18 passes through the coil opening of the other coil, thereby magnetically coupling the first and second coils 16, 18 to each other.

[0035] In order for the first and second coils 16, 18 to be magnetically coupled with a sufficient degree of magnetic coupling, as shown in FIG. 2 , the first and second coils 16, 18 are disposed adjacent to each other, i.e., spaced apart so as not to directly contact each other. In the first embodiment, the first and second coils 16, 18 are provided on the first and second surfaces 12a, 12b, respectively, of the sheet member 12, and therefore do not directly contact each other. This adjacent arrangement allows a relatively high density of magnetic flux generated by one of the first and second coils 16, 18 to pass through the coil opening of the other coil (when the first and second coils 16, 18 are spaced apart, the density of the magnetic flux passing through the respective coil openings 16c, 18c is low). As a result, the first and second coils 16, 18 can be magnetically coupled with a sufficient degree of magnetic coupling.

[0036] 2 , when viewed in the direction in which first winding axis C1 extends (Z-axis direction), second coil 18 is located outside coil opening 16 c of first coil 16. At the same time, when viewed in the direction in which second winding axis C2 extends (Z-axis direction), first coil 16 is located outside coil opening 18 c of second coil 18. In the first embodiment, when viewed in the thickness direction of sheet member 12 (Z-axis direction), first and second coils 16, 18 are disposed adjacent to each other such that second coil 18 is not present within coil opening 16 c of first coil 16 and first coil 16 is not present within coil opening 18 c of second coil 18. This allows magnetic flux generated by first coil 16 to pass through coil opening 16 c of first coil 16 without being obstructed by second coil 18. At the same time, the magnetic flux generated by the second coil 18 can pass through the coil opening 18c of the second coil 18 without being obstructed by the first coil 16. As a result, the first and second coils 16, 18 can generate a sufficient magnetic field efficiently.

[0037] 2 , in the first embodiment, the first coil 16 and the second coil 18 are in contact with each other when viewed in the thickness direction (Z-axis direction) of the sheet member 12. That is, the outer edge of the outermost conductor wire in the first coil 16 is in contact with the outer edge of the outermost conductor wire in the second coil 18. This brings the coil opening 16c of the first coil 16 and the coil opening 18c of the second coil 18 closer to each other. This allows the high-density magnetic flux generated by the first coil 16 to pass through the coil opening 18c of the second coil 18, and the high-density magnetic flux generated by the second coil 18 to pass through the coil opening 16c of the first coil 16. As a result, the first coil 16 and the second coil 18 can be magnetically coupled with each other with a sufficient degree of magnetic coupling.

[0038] Furthermore, in order to bring the coil opening 16c of the first coil 16 and the coil opening 18c of the second coil 18 closer to each other, in the first embodiment, when viewed in the thickness direction (Z-axis direction) of the sheet member 12, a portion of the second coil 18 with fewer turns than the other portions contacts the first coil 16. In the first embodiment, the second coil 18 has a four-turn portion (i.e., a portion where four conductor wires are arranged in parallel) and a five-turn portion (i.e., a portion where five conductor wires are arranged in parallel). The outermost conductor wire in the four-turn portion contacts the first coil 16. As a result, the coil openings 16c, 18c of the first and second coils 16, 18 are closer to each other than when the five-turn portion of the second coil 18 contacts the first coil 16. Note that if the first coil 16 has a portion with fewer turns than the other portions, that portion may contact the second coil 18.

[0039] Furthermore, in the first embodiment, the first and second coils 16 and 18 are rectangular when viewed in the direction in which the winding axes C1 and C2 extend (the Z-axis direction) so that a greater amount of high-density magnetic flux passes through the coil openings 16c and 18c of the first and second coils 16 and 18. The long sides of the first and second coils 16 and 18 are in contact when viewed in the thickness direction of the sheet member 12 (the Z-axis direction). This allows a greater amount of high-density magnetic flux to pass through the coil openings 16c and 18c than when the first and second coils 16 and 18 are, for example, circular. As a result, the first and second coils 16 and 18 are magnetically coupled with a sufficient degree of magnetic coupling. The first and second coils 16 and 18 are not limited to being rectangular; for example, one may be "D" shaped and the other an inverted "D" shaped. In this case, the linear portions of the first and second coils 16 and 18 are in contact with each other. That is, it is preferable that the portions of the first and second coils 16, 18 that contact each other are parallel to each other.

[0040] According to the first embodiment as described above, the wireless communication device 10 in which the antenna 20 and the RFIC chip 14 are connected via magnetic field coupling can be miniaturized while achieving a sufficient degree of magnetic field coupling.

[0041] Second Embodiment Fig. 7 is a perspective view of a wireless communication device according to a second embodiment of the present disclosure. Fig. 8 is a top view of the wireless communication device according to the second embodiment. Note that components of the second embodiment that are substantially the same as those of the first embodiment described above are denoted by the same reference numerals.

[0042] 7 and 8, in the second embodiment, the wireless communication device 110 has a sheet member 12 made of a dielectric material. The sheet member 12 is rectangular and has a first surface 12a and a second surface 12b opposite to the first surface 12a.

[0043] Fig. 9 is a diagram showing components provided on a first surface of a sheet member in a wireless communication device according to embodiment 2. Fig. 10 is a diagram showing components provided on a second surface of a sheet member in a wireless communication device according to embodiment 2.

[0044] 7 to 10 , in the second embodiment, the sheet member 12 is provided with an RFIC chip 14, a first coil 116, a second coil 118, and an antenna 20. Specifically, the RFIC chip 14 and the antenna 20 are provided on the first surface 12a of the sheet member 12. Furthermore, the first coil 116 and the second coil 118 are provided on the second surface 12b of the sheet member 12.

[0045] In the second embodiment, the first coil 116 includes two coil portions 116a and 116b wound in the same direction. In the second embodiment, the coil portions 116a and 116b have the same shape and are arranged point-symmetrically so that their outer peripheral ends are connected. That is, the coil portions 116a and 116b have the same number of turns and the same area of ​​the coil opening. The inner end of one coil portion 116a is connected to the first input / output terminal 14a of the RFIC chip 14 via a conductor pattern 136 and an interlayer connection conductor 138 provided on the first surface 12a of the sheet member 12. The inner end of the other coil portion 116b is connected to the second input / output terminal 14b of the RFIC chip 14 via a conductor pattern 140 and an interlayer connection conductor 142 provided on the first surface 12a of the sheet member 12.

[0046] Similarly, the second coil 118 also includes two coil portions 118a and 118b wound in the same direction. In the second embodiment, the coil portions 118a and 118b have the same shape and are arranged point-symmetrically so that their outer peripheral ends are connected. That is, the coil portions 118a and 118b have the same number of turns and the same area of ​​the coil opening. The inner end of one coil portion 118a is connected to the base end 30a of the first radiating portion 30 of the antenna 20 via an interlayer connecting conductor 144. The inner end of the other coil portion 118b is connected to the base end 32a of the second radiating portion 32 of the antenna 20 via an interlayer connecting conductor 146.

[0047] Both the first coil 116 and the second coil 118 are provided on the second surface 12b of the sheet member 12. Therefore, when viewed in the thickness direction (Z-axis direction) of the sheet member 12, the first coil 116 and the second coil 118 are arranged side by side with a gap between them. Specifically, the coil portion 116a of the first coil 116 and the coil portion 118a of the second coil 118 face each other with a gap between them, and the coil portion 116b of the first coil 116 and the coil portion 118b of the second coil 118 face each other with a gap between them.

[0048] With such a first coil 116 and second coil 118, when the open-type antenna 20 receives a signal (radio wave) from an external device (e.g., a reader / writer device), a current corresponding to the received signal flows from the antenna 20 to the second coil 118. This causes each of the two coil portions 118a and 118b of the second coil 118 to generate a magnetic field. At this time, the directions of the magnetic flux generated by the coil portions 118a and 118b are opposite to each other. For example, if the direction of the magnetic flux passing through the coil opening of one coil portion 118a is from the first surface 12a to the second surface 12b of the sheet member 12, the direction of the magnetic flux passing through the coil opening of the other coil portion 118b is from the second surface 12b to the first surface 12a.

[0049] Most of the magnetic flux generated by one coil portion 118a of the second coil 118 passes through the coil opening of one coil portion 116a of the first coil 116. At the same time, most of the magnetic flux generated by the other coil portion 118b of the second coil 118 passes through the opening of the other coil portion 116b of the first coil 116. Although the directions of the magnetic flux passing through the coil openings of the two coil portions 116a and 116b of the first coil 116 are different, because the winding directions of the coil portions 116a and 116b are the same, current flows in the same direction. This current drives the RFIC chip 14.

[0050] The reason for configuring the first coil 116 and the second coil 118 in this manner is to prevent current from flowing through the first and second coils 116, 118 when the wireless communication device 110 is placed in a specific magnetic field. This will be explained in more detail using FIG. 11 .

[0051] FIG. 11 is a diagram simply illustrating an example of use of the wireless communication device according to the second embodiment.

[0052] 11 , the wireless communication device 110 according to the second embodiment may be placed in a magnetic field in which a magnetic flux F travels in one direction. For example, the wireless communication device 110 may be attached to clothing, and needle reading may be performed on the clothing. When an electromagnetic induction needle reader is used for needle reading, the needle reader generates a magnetic field using a coil T and detects the presence of a needle in the magnetic field based on changes in the magnetic field.

[0053] Therefore, if the first coil (and / or second coil) of the wireless communication device is present in the magnetic field generated by the meter reader, the meter reader will erroneously detect the first coil as a needle. Specifically, for example, if the first coil is present in the magnetic field of the meter reader, the magnetic field causes a current to flow in the first coil. The flow of current causes the first coil to generate a magnetic field. The magnetic field of the first coil causes the meter reader to determine that a change has occurred in the magnetic field, and will erroneously detect the first coil as a needle.

[0054] To prevent such false detection of the first coil 116 by a needle reader, the first coil 116 includes two coil portions 116a and 116b wound in the same direction and connected at their outer circumferential ends. As shown in FIG. 11 , when the first coil 116 is placed in a magnetic field in which the magnetic flux F is oriented in the same direction, currents Ia and Ib flow through the two coil portions 116a and 116b, respectively. Because the magnetic flux F passing through the coil openings of the coil portions 116a and 116b is oriented in the same direction, the currents Ia and Ib generated by the magnetic field are oriented in opposite directions. Therefore, the first coil 116 does not substantially conduct current and does not substantially generate a magnetic field. As a result, false detection of the first coil 116 as a needle by a needle reader is prevented.

[0055] In order to prevent the first coil 116 from generating a magnetic field, the magnitudes of the currents Ia and Ib flowing through the two coil portions 116a and 116b must be substantially the same when the first coil 116 is placed in a magnetic field in which the magnetic flux F is oriented in the same direction. Similarly, the magnitudes of the currents flowing through the two coil portions 118a and 118b in the second coil 118 must also be substantially the same. In the case of the second embodiment, as shown in FIG. 10 , the coil portions 116a and 116b in the first coil 116 have the same shape, and the coil portions 118a and 118b in the second coil 118 also have the same shape. As a result, currents of the same magnitude flow through the two coil portions.

[0056] However, even if the shapes of the coil portions 116a, 116b (118a, 118b) in the first coil 116 (second coil 118) are different, by appropriately adjusting the number of turns and / or the area of ​​the coil opening, it is possible to make the magnitude of the current flowing through the coil portions 116a, 116b (118a, 118b) substantially the same when they are placed in a magnetic field with the same magnetic flux direction.

[0057] In the second embodiment, as in the first embodiment described above, the wireless communication device 110 in which the antenna 20 and the RFIC chip 14 are connected via magnetic field coupling can be miniaturized while achieving a sufficient degree of magnetic field coupling.

[0058] Although the present disclosure has been described above with reference to a number of embodiments, the present disclosure is not limited to these embodiments.

[0059] For example, in the case of the first embodiment described above, as shown in Fig. 2, the first coil 16 provided on the first surface 12a and the second coil 18 provided on the second surface 12b are in contact with each other when viewed in the thickness direction (Z-axis direction) of the sheet member 12. Also, in the case of the second embodiment described above, as shown in Fig. 8, the first coil 116 and the second coil 118 provided on the first surface 12a are arranged side by side with a gap between them when viewed in the thickness direction of the sheet member 12. However, the layout of the first and second coils in the embodiments of the present disclosure is not limited to these.

[0060] For example, when a first coil is provided on a first surface of a sheet member and a second coil is provided on a second surface of the sheet member, a portion of the conductor of the first coil may overlap a portion of the conductor of the second coil when viewed in the thickness direction of the sheet member. For example, when viewed in the thickness direction of the sheet member, the outermost conductor of the first coil may overlap the outermost conductor of the second coil. That is, the first coil and the second coil may partially overlap each other as long as the second coil is located outside the coil opening of the first coil when viewed in the extension direction of the first winding axis of the first coil and the first coil is located outside the coil opening of the second coil when viewed in the extension direction of the second winding axis of the second coil.

[0061] In the first embodiment, the first and second coils are provided on a common sheet member. However, the present disclosure is not limited to this. For example, the first and second coils may be provided on separate members, and these separate members may be directly or indirectly connected to each other.

[0062] Furthermore, in the first embodiment described above, the first and second coils 16, 18 are planar coils provided on the first and second surfaces 12a, 12b of the sheet member 12, respectively. However, the embodiments of the present disclosure are not limited to this. For example, the first and second coils may be helical coils provided on a multilayer substrate. In this case, for example, a "C"-shaped conductor pattern may be formed on each of the top surface, middle layer, and bottom surface of the multilayer substrate, and adjacent conductor patterns may be connected to each other via interlayer connection conductors to form a helical coil.

[0063] Furthermore, in the first embodiment described above, the first and second coils 16, 18 are provided on the first and second surfaces 12a, 12b of the sheet member 12, respectively, so that the first and second winding axes C1, C2 of the first and second coils 16, 18 are substantially parallel to each other. However, the embodiments of the present disclosure are not limited to this. The first and second coils may be provided on a member having a curved surface. For example, the first and second coils may be provided side by side with a gap between them on one curved surface of the member.

[0064] That is, various aspects of the present disclosure are as follows.

[0065] A first aspect is a wireless communication device having: a first coil having one or more turns; an RFIC chip having a first terminal connected to one end of the first coil and a second terminal connected to the other end of the first coil; a second coil having one or more turns and magnetically coupled to the first coil; and an open-type antenna connected to the second coil, wherein the first and second coils are arranged adjacent to each other so that the second coil is located outside a coil opening of the first coil when viewed in the extension direction of a first winding axis of the first coil, and so that the first coil is located outside a coil opening of the second coil when viewed in the extension direction of a second winding axis of the second coil.

[0066] A second aspect is the wireless communication device of the first aspect, wherein the first coil is planar, the second coil is planar, and the first winding axis of the first coil and the second winding axis of the second coil are parallel to each other.

[0067] A third aspect is a wireless communication device of the second aspect, further comprising a dielectric sheet member having a first surface and a second surface opposite to the first surface, wherein the first coil is provided on the first surface of the sheet member, and the second coil is provided on the second surface of the sheet member.

[0068] A fourth aspect is the wireless communication device of the third aspect, wherein the first coil and the second coil are in contact with each other when viewed in the thickness direction of the sheet member.

[0069] A fifth aspect is a wireless communication device of the fourth aspect, in which, when viewed in the thickness direction of the sheet member, one of the first and second coils is in contact with a portion of the other of the first and second coils that has a smaller number of turns than other portions of the other of the first and second coils.

[0070] A sixth aspect is the wireless communication device of the third aspect, wherein a portion of the conductor of the first coil and a portion of the conductor of the second coil overlap when viewed in the thickness direction of the sheet member.

[0071] A seventh aspect is a wireless communication device of any one of the first to sixth aspects, wherein the sheet member is rectangular when viewed in the thickness direction of the sheet member, and the antenna extends diagonally across the sheet member so that the open end of the antenna is located at a corner of the sheet member.

[0072] An eighth aspect is a wireless communication device of the second aspect, in which the first coil includes two coil sections each wound in the same direction and whose outer peripheral ends are connected to each other, and the second coil includes two coil sections each wound in the same direction and whose outer peripheral ends are connected to each other.

[0073] A ninth aspect is a wireless communication device of the eighth aspect, in which the two coil portions in the first coil have the same shape and are arranged point-symmetrically, and the two coil portions in the second coil have the same shape and are arranged point-symmetrically.

Claims

1. A wireless communication device comprising: a first coil having one or more turns; an RFIC chip having a first terminal connected to one end of the first coil and a second terminal connected to the other end of the first coil; a second coil having one or more turns and magnetically coupled to the first coil; and an open-type antenna connected to the second coil, wherein the first and second coils are arranged adjacent to each other so that the second coil is located outside a coil opening of the first coil when viewed in the extension direction of a first winding axis of the first coil, and so that the first coil is located outside a coil opening of the second coil when viewed in the extension direction of a second winding axis of the second coil.

2. The wireless communication device of claim 1, wherein the first coil is planar, the second coil is planar, and the first winding axis of the first coil and the second winding axis of the second coil are parallel to each other.

3. The wireless communication device according to claim 2, further comprising a dielectric sheet member having a first surface and a second surface opposite to the first surface, wherein the first coil is provided on the first surface of the sheet member, and the second coil is provided on the second surface of the sheet member.

4. The wireless communication device according to claim 3, wherein the first coil and the second coil are in contact with each other when viewed in the thickness direction of the sheet member.

5. A wireless communication device as described in claim 4, wherein, when viewed in the thickness direction of the sheet member, one of the first and second coils is in contact with a portion of the other of the first and second coils that has a smaller number of turns than other portions of the other of the first and second coils.

6. The wireless communication device according to claim 3, wherein a portion of the conductor of the first coil and a portion of the conductor of the second coil overlap when viewed in the thickness direction of the sheet member.

7. A wireless communication device according to any one of claims 1 to 6, wherein the sheet member is rectangular when viewed in the thickness direction of the sheet member, and the antenna extends diagonally across the sheet member so that an open end of the antenna is located at a corner of the sheet member.

8. The wireless communication device according to claim 2, wherein the first coil includes two coil sections that are wound in the same direction and whose outer peripheral ends are connected to each other, and the second coil includes two coil sections that are wound in the same direction and whose outer peripheral ends are connected to each other.

9. The wireless communication device according to claim 8, wherein the two coil sections of the first coil have the same shape and are arranged symmetrically about a point, and the two coil sections of the second coil have the same shape and are arranged symmetrically about a point.