RFID devices

Abstract

An RFID device (10) is provided. The RFID device (10) comprises a first loop antenna (14) embedded in the device body (12) and a second loop antenna (16) embedded in the device body (12). The first loop antenna (14) and the second loop antenna (16) partially overlap each other by a set distance (d). This results in suppression of cross-coupling between the first loop antenna (14) and the second loop antenna (16), enabling optimal use of the space available for the antennas on the device body (12). In this way, reliable operation of the two antennas within the desired communication range is obtained.

Description

Technical Field

[0001] The present disclosure generally relates to radio frequency identification (RFID) devices, and more particularly to RFID devices comprising a plurality of RFID antennas.

Background Art

[0002] Generally, RFID devices such as RFID cards, RFID tags, etc. comprise an RFID antenna and an integrated circuit connected to the RFID antenna. When an electromagnetic field emitted by a reader device is present, the RFID antenna supplies energy from the electromagnetic field to the integrated circuit, and the integrated circuit may communicate with the reader device using a radio frequency (RF) communication protocol. In this way, for example, data can be read from the memory associated with the integrated circuit and, if desired, written to that memory.

[0003] Patent Document 1 discloses an IC tag including a first inlet formed by patterning a first antenna carrying a first IC chip in a loop shape near the outer peripheral area of an IC card. A small inlet comprising a second antenna, a second IC chip, and a matching circuit is attached to the top or bottom surface of the card intersecting at a right angle with a part of the first loop antenna. With this antenna layout, it is possible to miniaturize the second antenna by using the first antenna as an auxiliary antenna.

[0004] The present disclosure is at least partially directed to improving or overcoming one or more aspects of conventional systems.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

[0006] According to one aspect of the present disclosure, an RFID device comprises a device body, a first loop antenna embedded in the device body, the first loop antenna extending in a first plane, and a second loop antenna embedded in the device body. The second loop antenna partially overlaps the first loop antenna when viewed in a direction perpendicular to the first plane.

[0007] Other features and aspects of this disclosure will become apparent from the following description and accompanying drawings. [Brief explanation of the drawing]

[0008] [Figure 1] Plan view of an RFID device in accordance with this disclosure. [Figure 2] A diagram illustrating antenna coupling between two loop antennas in accordance with this disclosure. [Figure 3] Plan view of another RFID device in accordance with this disclosure. [Figure 4] A plan view of another embodiment of an RFID device according to this disclosure. [Modes for carrying out the invention]

[0009] The following is a detailed description of exemplary embodiments of the present disclosure. The exemplary embodiments described herein are intended to teach the principles of the present disclosure and enable those skilled in the art to implement and use the present disclosure in many different environments and for many different applications. Accordingly, the exemplary embodiments are not intended to be, nor should they be considered, a limited description of the scope of protection. Rather, the scope of protection is defined by the appended claims.

[0010] This disclosure is at least in part based on the recognition that in applications where two or more RFID antennas, for example two HF antennas, are provided to a single RFID device such as an RFID card, interference can exist between the two antennas, resulting in a frequency shift in the antenna's tuning frequency. For example, if an RFID card comprises a first loop antenna operating at a tuning frequency of 15 MHz and a second loop antenna operating at a tuning frequency of 16 MHz, both antennas are provided to one RFID card, and their respective tuning frequencies may shift to 14 MHz and 17 MHz, respectively. However, this can result in a degradation of the RFID card's performance. In particular, it is recognized that the size of individual antennas should be as large as possible to obtain the maximum possible communication range. Traditionally, this has been achieved by arranging two antennas such that one is positioned inside the other, i.e., the first antenna covers the maximum possible area of ​​the RFID card and the second antenna is positioned inside the first antenna. This results in the aforementioned interference.

[0011] It is recognized that the above problem can be overcome or mitigated when two loop antennas are provided such that there is only partial overlap between the two antennas. In particular, the effects of interference between two antennas can also be reduced by positioning the two antennas so that they are relatively far apart from each other, which is recognized as resulting in a substantial reduction in the size of the two antennas. On the other hand, it has been found that providing the two antennas to partially overlap by a certain amount has almost the same effect in reducing interference between antennas.

[0012] In this regard, it has been recognized that it is advantageous to provide a loop antenna having a shape that can be considered roughly D-shaped, that is, a shape comprising one or more straight portions extending along one or more outer edges of the RFID device and a roughly arc-shaped portion provided in an overlapping area particularly close to the central portion of the RFID device. In this way, it is possible to make the size of each antenna as large as possible while reducing interference between each antenna.

[0013] The present invention is also based on the recognition that the above concept can be generalized to two or more antennas by, for example, providing a third antenna between a first antenna and a second antenna. In this case, it is possible to form one or more overlapping regions between the first antenna and the third antenna, and / or between the third antenna and the second antenna, while obtaining good performance for each of the antennas.

[0014] This disclosure is also at least in part based on the recognition that when two antennas are used for different applications, one application may require a considerably larger communication range than another. In this case, the two antennas may be substantially different in size, i.e., a first antenna for a larger communication range may be considerably larger than a second antenna for a smaller communication range. In this way, it is possible to achieve a communication range of, for example, 0.5 to 1 m for the first antenna, while the second antenna may be used for applications where a communication range of up to 0.1 m is sufficient. For example, the first application may be an access control application where the holder of the RFID device wants to pass through an entrance or gate without having to bring the RFID device very close to the reader. On the other hand, the second application may be an electronic ticketing or payment application for, for example, a public transport system, where the RFID device is usually brought very close to the corresponding reader.

[0015] In addition, the following describes an example in which two antennas are provided as part of an RFID card having a commonly used size (e.g., approximately 85.6 mm × 54 mm) as defined by a well-known standard, although it is recognized that the concepts described above and below can also be generalized to other RFID devices having different sizes and / or geometric shapes. For example, this can be achieved by scaling the size and / or overlap appropriately described below.

[0016] Referring hereto to the drawings, Figure 1 shows a plan view of an RFID device 10 according to this disclosure. In the example shown in Figure 1, the RFID device 10 is configured as a substantially rectangular RFID card that can be used as an access card, debit card, credit card, etc. However, it is understood that the RFID device 10 may be configured in a different shape, such as an RFID tag, token, etc. Furthermore, the RFID device 10 may be used for any appropriate purpose, for example, as a means of payment, as a means of identifying the user / holder of the RFID device, etc., to obtain access to buildings, etc. The range of possible applications of such RFID devices is well known and therefore will not be described in detail herein.

[0017] As shown in Figure 1, the RFID device 10 comprises a device body 12 formed in the shape of a substantially rectangular card or sheet. The device body 12 may be polycarbonate or other substrates commonly used for RFID cards. Furthermore, as shown in Figure 1, the RFID device 10 comprises a first loop antenna 14 embedded in the device body 12. In particular, in exemplary embodiments, the first loop antenna 14 extends into a first plane 15 parallel to the top and bottom surfaces of the device body 12. However, it is understood that this is not necessarily required in other embodiments.

[0018] The RFID device 10 further comprises a second loop antenna 16 embedded in the device body 12. Here, as shown in Figure 1, the second loop antenna 16 is provided such that it partially overlaps the first loop antenna 14 when viewed in a direction perpendicular to the first plane 15. For example, the first loop antenna 14 may be provided in a first layer of the device body 12 by known means, and the second loop antenna 16 may be located in a second layer of the device body 12, the second layer being provided above or below the first layer, and the layers being combined to form the RFID device 10. It is well known that loop antennas such as loop antenna 14 and loop antenna 16 are provided on each substrate forming part of the RFID device 10, for example, an RFID card, and a detailed explanation is omitted. However, the exemplary embodiments relating to RFID cards are not limiting to this disclosure and it is understood that other arrangements of the loop antennas 14, 16 are possible. For example, the second loop antenna 16 does not necessarily have to extend in a plane parallel to the first plane 15. For example, the second loop antenna 16 can extend into a plane that extends at an angle to the first plane 15. Similarly, the disclosure is not limited to the exemplary RIFD card shown in Figure 1, and any RFID device or device body having any suitable shape or size can be used depending on the desired application.

[0019] As shown in Figure 1, the RFID device 10 further comprises a first integrated circuit 22 connected to a first loop antenna 14 and configured to perform RFID communication via the first loop antenna 14, and a second integrated circuit 24 connected to a second loop antenna 16 and configured to perform RFID communication via the second loop antenna 16. The connections of each integrated circuit to each loop antenna are well known, as are the performance of RFID communication using such circuits. Therefore, a detailed description is omitted herein. However, it is generally understood that each combination of an integrated circuit and a loop antenna is configured to perform RFID communication within a given wavelength / frequency range and within a communication range essentially determined by the size of the antenna. This will be described in more detail below. However, it should be noted that according to this disclosure, the first loop antenna 14 and the first integrated circuit 22 are configured for different applications than the second loop antenna 16 and the second integrated circuit 24, for example, to perform RFID communication at different antenna tuning frequencies, at will, and within different communication ranges. It should also be noted that in some embodiments, both the first loop antenna 14 and the second loop antenna 16 may be connected to a single integrated circuit, which is configured to selectively perform RFID communication via the first loop antenna 14 and the second loop antenna 16.

[0020] As described above, the first loop antenna 14 and the second loop antenna 16 are provided such that, when viewed perpendicular to the first plane 15, the second loop antenna 16 partially overlaps with the first loop antenna 14. As used herein, the expression “partially overlapping” is understood to mean that the two antennas do not completely overlap each other, or that one antenna is provided inside an area covered by the other antenna. In other words, at least the second loop antenna 16 has an overlapping portion 16a that overlaps with the first loop antenna 14 when viewed perpendicular to the first plane 15, and a non-overlapping portion 16b that does not overlap with the first loop antenna 14 when viewed perpendicular to the first plane 15. As shown in Figure 1, in an exemplary embodiment, the overlapping portion 16a is part of an arc-shaped section of the second loop antenna 16. However, this does not limit the disclosure, and it is understood that the overlapping portion 16a may also be formed as one or more linear sections of the second loop antenna 16, which may overlap, for example, with an arc-shaped section of the first loop antenna 14, or one or more linear sections may be provided to form an overlapping portion in each of the two antennas.

[0021] As shown in Figure 1, in an exemplary embodiment, the first loop antenna 14 is approximately D-shaped when viewed perpendicular to the first plane 15. Here, "approximately D-shaped" means a shape in which three straight sections are connected to each other at a 90° angle, and the ends of opposing straight sections are connected to each other by arc-shaped sections such as the arc-shaped overlap 16a of the second loop antenna 16 or the corresponding overlap 14a of the first loop antenna 14. However, the D-shape shown in Figure 1 is merely an example, and it is understood that other shapes of loop antennas 14, 16, such as rectangular, polygonal, circular, or elliptical shapes, may be used.

[0022] Particularly, due to the D-shape of the first loop antenna 14 and the second loop antenna 16, it is possible to maximize the surface coverage rate of each antenna on the rectangular device body 12, similar to the case of a generally used RFID card. Here, the first loop antenna 14 is disposed on one side of the device body 12, a straight section of the first loop antenna 14 extends along the outer edge of the device body 10, and an arcuate overlapping portion 14a is provided toward the center of the device body 10. Similarly, the second loop antenna 16 is disposed on the opposite side of the device body 12, a straight section of the second loop antenna 16 extends parallel to the edge of the device body 12, and an arcuate overlapping portion 16a extends toward the center of the device body 12. In this way, it is possible to maximize the size (area) of each antenna, and at the same time, it is possible to reduce the coupling through the overlapping portion at the center of the device body 12.

[0023] As shown in FIG. 1, according to the present disclosure, the optimized (maximum) dimension d of the overlapping region 18 of the loop antennas 14 and 16 along the first direction in the first plane 15 is 0.05 to 0.25 times the total (maximum) dimension W of the device body 12 along the first direction, and / or about 5 mm to about 20 mm, preferably about 10 mm to about 15 mm, particularly about 13 mm. Here, generally, there is a direction in which the loop antennas 14 and 16 are disposed (for example, as shown in FIG. 1, the direction between two opposite ends of the loop antennas 14 and 16 in the device body 12, or a direction parallel to one of the sides of the device body 12, etc., the direction in which the device body 12 extends), and this direction is identified as the first direction. It is understood that the maximum dimension d is the dimension (length, extent) of the overlapping region 18 along this first direction. The same applies to the total dimension W of the device body 12. In the example shown in FIG. 1, the total dimension W of the device body 12 is the width along the long side of the rectangular shape constituting the device body 12. Similarly, the first direction is the direction along the long side of the device body 12. The overlapping region 18 is formed near the center of the device body 12, and the maximum dimension d is determined by the distance between adjacent ends of the first loop antenna 14 and the second loop antenna 16 along the first direction.

[0024] FIG. 2 is a diagram showing the cross-coupling effect (i.e., frequency shift due to cross-coupling) of the first loop antenna 14 and the second loop antenna 16. Here, the delta shown in FIG. 2 corresponds to the observed frequency shift of the antenna for antennas provided apart from each other (as shown at the top of FIG. 1). As can be seen in FIG. 2, when the RFID device 10 is an RFID card having a standard size of about 85.6 mm × 54 mm, the frequency shift is maximum in the case of very small overlap, and it has been found that it decreases with an increase in overlap up to an optimal overlap between about 5 mm and about 20 mm, preferably between about 13 mm and 15 mm. When the overlap further increases, the frequency shift increases again. It has been found that the overlap between the loop antennas 14 and 16 should be about 5 mm to about 20 mm, preferably about 10 mm to about 15 mm, particularly about 13 mm, so as to minimize the coupling between the two antennas of such a standard RFID card.

[0025] As described above, the present disclosure is not limited to the application to an RFID card having a standard size. For example, when the RFID device 10 has a size with a rectangular shape but is smaller or larger than the standard card size, it is clear that the optimal overlap needs to be enlarged or reduced according to the size of the RFID device 10. Therefore, generally, it has been found that minimization or optimization of the interference between the loop antennas 14 and 16 can be achieved when the maximum dimension d of the overlap region 18 (i.e., the overlap) is, for example, 0.05 to 0.25 times the total (maximum) dimension W of the device body 12 along the first direction. Here, it is again pointed out that the shape of the device body 12 is not limited to the rectangular shape shown in FIG. 1 and may be any shape. Similarly, the shapes of the first loop antenna 14 and the second loop antenna 16 are not limited to the D shape shown in FIG. 1.

[0026] Furthermore, in the example shown in Figure 1, the device body 12 is substantially planar, and the first plane 15 is parallel to the opposing surfaces of the device body 12, but this is not necessarily required. The device body 12 can have any suitable shape, e.g., spherical or cubic, and the first plane 15 can be positioned inside the device body 12 in any desired orientation. However, considering the desired performance, in order to provide the largest possible space for positioning the first loop antenna 14 and the second loop antenna 16, the first plane 15 is generally positioned to have the largest possible spread inside the device body 12, and the aforementioned first orientation is generally understood to be the direction in the first plane 15 extending from the first loop antenna 14 (e.g., the center of the first loop antenna 14) to the second loop antenna 16 (e.g., the center of the second loop antenna 16). However, in this regard, it should be noted again that the plane on which the second loop antenna 16 extends does not necessarily have to be parallel to the first plane 15, depending on the shape of the device body 12, for example.

[0027] In some embodiments, at least one of the first loop antenna 14 and the second loop antenna 16 is an HF antenna configured to perform RFID communication at a tuning frequency of about 13.5 MHz to about 18 MHz within a range of 0.1 m to 1.5 m (or 2 m). In particular, the first loop antenna 14 and the second loop antenna 16 may be configured for different applications, in particular, to perform RFID communication at different antenna tuning frequencies of, for example, 15 MHz and 16 MHz. Here, in some embodiments, the first loop antenna 14 and the second loop antenna 16 may be substantially the same size and optionally have substantially the same number of turns, for example, 2 to 10 turns.

[0028] However, in other embodiments, the first loop antenna 14 and the second loop antenna 16 may have substantially different sizes, for example, the maximum dimension of the first loop antenna 14 being about 1.5 to 2 times the maximum dimension of the second loop antenna 16 when viewed in a direction perpendicular to the first plane 15. In other words, in the exemplary embodiment shown in Figure 1, the size of the first loop antenna 14 along the direction parallel to the long side of the device body 12 may be about 1.5 to 2 times the corresponding size of the second loop antenna 16. This makes it possible to widen the communication range of the first loop antenna 14 while narrowing the communication range of the second loop antenna 16. This may be useful and / or desirable when the first loop antenna 14 and the second loop antenna 16 are used for different applications, for example, when the first loop antenna 14 is used for access control and the second loop antenna 16 is used for payment or ticketing applications. In this case, for example, the first loop antenna 14 may have a communication range of 0.5 to 1 m, and the second loop antenna 16 may have a communication range of 2 to 10 cm. Similarly, the first loop antenna 14 and the second loop antenna 16 may have different numbers of turns.

[0029] Figure 3 shows another RFID device 10 according to the present disclosure. The RFID device shown in Figure 3 is essentially the same as the RFID device 10 shown in Figure 1, except for the arrangement of the loop antennas. In the embodiment shown in Figure 1, the loop antennas 14, 16 are arranged along the long side of the rectangular device body 12. In contrast, in the embodiment shown in Figure 3, the loop antennas 14, 16 are arranged along the short side of the device body 12. In other words, the extended linear sections of the loop antennas 14, 16 extend along the long side of the rectangular device body 12, on both sides of the device body 12 in the height direction H of the device body 12. Again, in some embodiments, the RFID device may be a standard-sized card having dimensions of approximately 85.6 mm × 54 mm. However, as stated above, the size of the RFID device 10 is not limited to such standard sizes, and the overlaps d described below can be scaled up or down according to the size of the RFID device 10 without departing from the present disclosure.

[0030] In the embodiment shown in Figure 3, the maximum dimension d of the overlapping region 18 of the loop antennas 14, 16 along the first direction in the first plane 15 is 0.10 to 0.40 times the maximum dimension H of the device body 12 along the first direction, and / or about 5 mm to about 20 mm, preferably about 10 mm to about 15 mm, and in particular about 11 mm, relative to the size of a standard card.

[0031] From the above, it is understood that the first direction of this disclosure, which essentially determines the overlap d (i.e., the maximum dimension or length of this overlap along the specified first direction), is a direction appropriately selected, particularly in the first plane 15. Here, in the case of a rectangular device body 12, it is understood that the directions extending parallel to the long and short sides of the device body 10, respectively, are an obvious choice for the first direction, i.e., the direction in which the first loop antenna 14 and the second loop antenna 16 are positioned. Naturally, it is understood that for device bodies 12 having different shapes, e.g., circular or elliptical, there are other appropriate choices for the first direction, e.g., the diameter of the circular device body 12, or the maximum dimension of the elliptical device body 12, etc. In general, the first direction (i.e., the direction of the arrangement of the loop antennas 14, 16) is selected such that the loop antennas can cover the maximum area on the device body 12, i.e., the loop antennas 14, 16 are positioned on the device body 12 such that they can cover the maximum area. Clearly, with respect to the D-shaped loop antennas 14 and 16 shown in Figure 3, this is the case when the first direction is either along the long side or the short side of the rectangular device body 12.

[0032] The arrangement shown in Figure 3 has the advantage, compared to the arrangement shown in Figure 1, that when a user holds the device body 12, they may tend to hold it near one of its shorter sides. However, in this case, the performance of one of the loop antennas 12, 14 may be reduced compared to the performance of the other of the loop antennas 14, 16. Clearly, this can be mitigated by the arrangement shown in Figure 3.

[0033] Furthermore, in the embodiment shown in Figure 3, the loop antennas 14 and 16 may have different sizes as described above, but the size of the overlapping region 18 may remain essentially the same. For example, in the embodiment shown in Figure 3, for a standard card, the maximum dimension d of the overlapping region 18 may be 5 to 20 mm, for example, about 11 mm, regardless of the size of the loop antennas 14 and 16.

[0034] Figure 4 shows another embodiment according to the present disclosure, in which a third loop antenna 30 is embedded in the device body 12, and the RFID device 10 can be used for three different applications. Here, the third loop antenna 30 may be connected to the integrated circuit 32 by known methods. As shown in Figure 4, the third loop antenna 30 partially overlaps the second loop antenna 16 when viewed in a direction perpendicular to the first plane 15. For example, at least one of the first loop antenna 14 and the third loop antenna 30 may be D-shaped, as in the embodiment shown in Figure 1, while the second loop antenna 16 may be rectangular, circular, or elliptical and may overlap both the first loop antenna 14 and the third loop antenna 30. The maximum dimension d of the overlapping region 18 may be set as described above, as may the maximum dimension e of the overlapping region 19 formed between the second loop antenna 16 and the third loop antenna 30. At the same time, the tips of the first loop antenna 14 and the third loop antenna 30 may be separated from each other by a distance S, which may be similar to the maximum dimensions d and e, as shown in Figure 4.

[0035] It is understood that the exemplary number of antennas in Figure 4 is merely an example and not limiting. Therefore, in other embodiments, it is possible to provide three or more antennas on the device body 12 with corresponding overlaps between two or more adjacent antennas, as long as the desired communication range of each antenna is guaranteed. Here, it is understood that the arrangement of the individual antennas is not limited to the arrangement along the first direction as shown in Figure 4. In other words, for example, a third loop antenna 30 may extend at an angle to the first loop antenna 12, or three or more loop antennas may be arranged in a star shape so as to overlap each other in a common central overlapping region. Industrial applicability As described above, the RFID device according to the present invention makes it possible to arrange two or more loop antennas for different applications on a single RFID device, such as an RFID card. By providing two or more loop antennas so as to overlap by a given distance, interference between the two antennas can be minimized or reduced, and the desired communication range can be obtained by optimal use of the available space on the RFID device. In particular, two or more applications that perform RFID communication in their respective optimal antenna tuning frequency ranges of 13.5 MHz to 18 MHz can be provided on the same device without causing unwanted frequency shifts due to interference between antennas. This makes it possible to reliably provide different functions of the RFID device for use, for example, in access control applications and ticketing or payment applications.

[0036] It is understood that the foregoing description provides examples of the systems and methods disclosed. However, other implementations of this disclosure are intended to differ in detail from the examples given above. All references to this disclosure or its embodiments are intended to refer to the specific embodiment being discussed at that time and are not intended to imply any limitation on the general disclosure.

[0037] The descriptions of value ranges in this specification are intended solely as abbreviations for referring individually to each distinct value that falls within that range, unless otherwise indicated herein, and each distinct value is incorporated herein as if it were individually described herein. All method steps described herein may be performed in any suitable order unless otherwise indicated or unless it is clearly inconsistent with the context.

[0038] While preferred embodiments of this disclosure have been described herein, improvements and modifications may be incorporated without departing from the scope of the following claims.

Claims

1. RFID device (10), The device body (12) and A first loop antenna (14) embedded in the device body (12), the first loop antenna (14) extending in a first plane (15), The device comprises a second loop antenna (16) embedded in the device body (12), The RFID device wherein the second loop antenna (16) partially overlaps with the first loop antenna (14) when viewed in a direction perpendicular to the first plane (15).

2. The RFID device according to claim 1, wherein the second loop antenna (16) has an overlapping portion (16a) that overlaps with the first loop antenna (14) when viewed in the direction perpendicular to the first plane (15), and a non-overlapping portion (16b) that does not overlap with the first loop antenna (14) when viewed in the direction perpendicular to the first plane (15).

3. The RFID device according to claim 2, wherein the overlapping portion (16a) is part of the arc-shaped section of the second loop antenna (16).

4. The first loop antenna (14) is approximately D-shaped when viewed in the direction perpendicular to the first plane (15), The RFID device according to any one of claims 1 to 3, wherein the second loop antenna (16) is substantially D-shaped when viewed in the direction perpendicular to the first plane (15).

5. The RFID device according to any one of claims 1 to 4, wherein the maximum dimension (d) of the overlapping region (18) of the loop antennas (14, 16) along the first direction in the first plane (15) is 0.05 to 0.40 times, preferably 0.10 to 0.25 times, or about 5 mm to about 20 mm, preferably about 10 mm to about 15 mm, particularly about 11 mm or about 13 mm, or both, of the maximum dimension (W, H) of the device body (12) along the first direction.

6. The RFID device according to claim 5, wherein the device body (12) is substantially rectangular in shape, and the first direction is parallel to the long side or short side of the device body (12) on which the loop antennas (14, 16) are arranged.

7. The RFID device according to claim 5 or 6, wherein the first direction is the direction extending from the center of the first loop antenna (14) toward the second loop antenna (16) in the first plane (15).

8. The RFID device according to any one of claims 1 to 7, wherein at least one of the first loop antenna (14) and the second loop antenna (16) is an HF antenna configured to perform RFID communication at a tuned frequency of approximately 13.5 MHz to approximately 18 MHz within a range of 0.1 m to 1.5 m.

9. The RFID device according to claim 8, wherein the first loop antenna (14) and the second loop antenna (16) are configured to perform RFID communication for different applications, in particular at different tuning frequencies, for example, 15 MHz and 16 MHz.

10. The RFID device according to any one of claims 1 to 9, wherein the first loop antenna (14) and the second loop antenna (16) are substantially the same size.

11. The RFID device according to any one of claims 1 to 9, wherein the first loop antenna (14) and the second loop antenna (16) are of different sizes, and the maximum dimension of the first loop antenna (14) is about 1.5 to 2 times the maximum dimension of the second loop antenna (16) when viewed in the direction perpendicular to the first plane (15).

12. A first integrated circuit (22) is connected to the first loop antenna (14) and configured to perform RFID communication via the first loop antenna (14), The RFID device according to any one of claims 1 to 11, further comprising: a second integrated circuit (24) connected to the second loop antenna (16) and configured to perform RFID communication via the second loop antenna (16).

13. The RFID device according to any one of claims 1 to 11, further comprising integrated circuits (22, 24) connected to the first loop antenna (14) and the second loop antenna (16) and configured to selectively perform RFID communication via the first loop antenna (14) and the second loop antenna (16).

14. The RFID device according to any one of claims 1 to 13, further comprising a third loop antenna (30) embedded in the device body (12), wherein the third loop antenna (30) partially overlaps with the second loop antenna (16) when viewed in the direction perpendicular to the first plane (15).

15. The RFID device according to claim 14, wherein at least one of the first loop antenna (14) and the third loop antenna (30) is D-shaped, and the second loop antenna (16) is rectangular, circular, or elliptical.

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