Loop antenna

Abstract

A loop antenna (1) has a plurality of loop portions, the plurality of loop portions are formed by one linear pattern, and the plurality of loop portions include a first loop portion (10) and a second loop portion (20).

Description

Loop antenna

[0001] The present disclosure relates to loop antennas.

[0002] Patent Document 1 discloses a loop antenna that transmits power wirelessly.

[0003] International Publication No. 2016 / 016964

[0004] For example, a reader / writer is provided with a loop antenna as disclosed in Patent Document 1. When an IC (Integrated Circuit) card and a reader / writer approach each other, an induced voltage is generated in the loop antenna of the IC card, enabling communication between the IC card, which does not have a power source, and the reader / writer. However, even when the IC card and the reader / writer approach each other, if the center of the loop antenna of the IC card and the center of the loop antenna of the reader / writer are misaligned, the induced voltage generated in the IC card becomes small, and communication between the IC card and the reader / writer may not be possible.

[0005] Therefore, the present disclosure provides a loop antenna that can suppress a decrease in induced voltage due to misalignment with a counterpart loop antenna.

[0006] The loop antenna according to the present disclosure is a loop antenna provided on a substrate, and when a loop portion is a pattern that goes around once around an arbitrary point on the substrate, the loop antenna has a plurality of the loop portions, and the plurality of loop portions are formed by a single linear pattern, and the plurality of loop portions include a first loop portion and a second loop portion, and the single pattern is configured in the order of the first loop portion and the second loop portion from one end to the other end of the single pattern, and the first loop portion has a first portion and a second portion that face each other in a first direction, and the second loop portion has a third portion and a fourth portion that face each other in the first direction, and when the substrate is viewed in a plane, the first portion, the second portion, the third portion, and the fourth portion are arranged in the order of the first portion, the third portion, the second portion, and the fourth portion in the first direction.

[0007] These comprehensive or specific aspects may be realized by a system, an apparatus, a method, a recording medium, or a computer program, or may be realized by any combination of a system, an apparatus, a method, a recording medium, and a computer program.

[0008] According to the loop antenna of the present disclosure, it is possible to suppress a decrease in induced voltage due to misalignment with the counterpart loop antenna.

[0009] FIG. 1 is a front perspective view showing a first example of a loop antenna according to an embodiment; FIG. 2 is a front perspective view showing an example of a conventional loop antenna; FIG. 3 is a graph showing induced voltages for each offset amount generated in a counterpart loop antenna by the first example and the conventional loop antenna; FIG. 4 is a front perspective view showing a second example of a loop antenna according to an embodiment; FIG. 5 is a graph showing induced voltages for each offset amount generated in a counterpart loop antenna by the second example and the conventional loop antenna; FIG. 6 is a graph showing induced voltages for each offset amount generated in a counterpart loop antenna by the second example and the conventional loop antenna; FIG. 7 is a front perspective view showing a third example of a loop antenna according to an embodiment; FIG. 8 is a front perspective view showing a fourth example of a loop antenna according to an embodiment; FIG. 9 is a graph showing magnetic field strengths of the third example, the fourth example, and the conventional loop antenna; FIG. 10 is a graph showing induced voltages for each offset amount generated in a counterpart loop antenna by the third example, the fourth example, and the conventional loop antenna.

[0010] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present disclosure.

[0011] (Embodiments) Loop antennas according to embodiments will be described below with reference to Fig. 1 to Fig. 10. First to fourth examples will be described below.

[0012] First, the first example will be described.

[0013] FIG. 1 is a front perspective view showing a first example of a loop antenna 1 according to an embodiment. The loop antenna 1 is provided on a substrate, but in FIG. 1, the substrate is made transparent to show only the loop antenna 1. In FIGS. 4, 7, and 8, which will be described later, the substrate is also made transparent to show only the loop antenna 1. For example, the substrate is double-sided, and the loop antenna 1 is provided on both the front and back surfaces of the substrate. Therefore, in FIG. 1, a portion of the loop antenna 1 provided on the front surface of the substrate and a portion provided on the back surface of the substrate are shown partially overlapping. The loop antenna 1 is formed, for example, by a copper foil pattern on the substrate. For example, the loop antenna 1 is provided in a reader / writer to wirelessly transmit power to an IC card and communicate with the IC card wirelessly.

[0014] When a loop portion is a pattern that goes around an arbitrary point on the substrate, the loop antenna 1 has multiple loop portions. The multiple loop portions are formed by a single linear pattern. Each of the multiple loop portions has a rectangular shape. For example, loop antennas on IC cards often have a rectangular shape, and by having the multiple loop portions also have a rectangular shape like the loop antenna on the IC card, the induced voltage generated in the opposing loop antenna (the loop antenna on the IC card) can be increased.

[0015] The multiple loop sections include a first loop section 10 and a second loop section 20. In the first example loop antenna 1, the multiple loop sections are two loop sections, the first loop section 10 and the second loop section 20. In other words, the first loop section 10 and the second loop section 20 are formed by a single pattern. For example, a feed point is provided at one end A of the single pattern, and unbalanced feeding is performed. Note that feed points may also be provided at both one end A and the other end B of the single pattern, and balanced feeding may be performed.

[0016] One pattern is configured from one end A to the other end B, in the order of the first loop portion 10 and the second loop portion 20. Specifically, the first loop portion 10 and the second loop portion 20 are continuous, with one end of the first loop portion 10 being one end A, the other end of the first loop portion 10 being one end of the second loop portion 20, and the other end of the second loop portion being the other end B. For convenience, the boundaries between the first loop portion 10 and the second loop portion 20 are referred to as the other end of the first loop portion 10 and one end of the second loop portion 20, but in reality, the boundaries between the first loop portion 10 and the second loop portion 20 are not visible.

[0017] The first loop portion 10 has a first portion 11 and a second portion 12 that face each other in a first direction. In the first example, the first direction is the up-down direction on the paper surface of FIG. 1 . Because each of the multiple loop portions has a rectangular shape, the first portion 11 and the second portion 12 are sides that face each other in the first direction. The first portion 11 constitutes the one end A side of the first loop portion 10 relative to the second portion 12 (i.e., the one end side of the first loop portion 10).

[0018] The second loop portion 20 has a third portion 21 and a fourth portion 22 that face each other in the first direction. Since each of the multiple loop portions has a rectangular shape, the third portion 21 and the fourth portion 22 are sides that face each other in the first direction. The third portion 21 constitutes the second loop portion 20 closer to one end A than the fourth portion 22 (i.e., closer to one end of the second loop portion 20).

[0019] 1 , the first portion 11, the second portion 12, the third portion 21, and the fourth portion 22 are arranged in the first direction in the order of first portion 11, third portion 21, second portion 12, and fourth portion 22. Specifically, when the substrate is viewed in the plan view, the first portion 11, the second portion 12, the third portion 21, and the fourth portion 22 are arranged on a virtual line extending in the first direction in the order of first portion 11, third portion 21, second portion 12, and fourth portion 22. When the substrate is viewed in the plan view, the distance between the first portion 11 and the third portion 21 and the distance between the second portion 12 and the fourth portion 22 (i.e., the amount of deviation in the first direction) is greater than the pattern width of one of the patterns constituting the loop antenna 1. For example, the distance between the first portion 11 and the third portion 21 and the distance between the second portion 12 and the fourth portion 22 may be 4 mm or more, 6 mm or more, or 8 mm or more.

[0020] The effects achieved by forming the loop antenna 1 so that the first part 11, the second part 12, the third part 21, and the fourth part 22 are arranged in the order of first part 11, third part 21, second part 12, fourth part 22 in the first direction, i.e., so that the first loop part 10 and the second loop part 20 are offset in the first direction, will be explained in comparison with conventional loop antennas.

[0021] 2 is a front perspective view showing an example of a conventional loop antenna 100. In the conventional loop antenna 100, each loop portion is provided adjacent to the other loop portion at approximately the same position. Therefore, in the conventional loop antenna 100, the amount of deviation between the loop portions is smaller than the pattern width of one of the patterns constituting the loop antenna 100.

[0022] For example, the vertical size (first direction) of the loop antenna 1 of the first example and the conventional loop antenna 100 is 33 mm, and the horizontal size (second direction intersecting with the first direction) is 36 mm. In addition, the distance between the third portion 21 and the second portion 12 of the loop antenna 1 of the first example is a mm, and the effects were verified for each of the cases where a = 25, a = 21, and a = 17.

[0023] FIG. 3 is a graph showing the induced voltages for each offset amount that are generated in the counterpart loop antenna by the first example and the conventional loop antenna.

[0024] When an IC card and a reader / writer come close to each other, an induced voltage is generated in the loop antenna of the IC card, enabling communication between the IC card, which does not have a power source, and the reader / writer. However, even when the IC card and the reader / writer come close to each other, if the center of the loop antenna of the IC card and the center of the loop antenna of the reader / writer are misaligned, the induced voltage generated in the IC card becomes small, and communication between the IC card and the reader / writer may not be possible. In contrast, the loop antenna 1 of the first example can suppress the decrease in induced voltage caused by misalignment with the other loop antenna (the loop antenna of the IC card).

[0025] 3, the horizontal axis represents the amount of deviation (called the offset) between the center of the loop antenna of the IC card and the center of the loop antenna 1 or 100, and the vertical axis represents the induced voltage generated in the loop antenna of the IC card. For example, the offset is the amount of deviation in the first direction. For example, in this example, the standard value for the induced voltage is 1.5 V, and it is assumed that when an induced voltage of 1.5 V or more is generated, the reader / writer and the IC card can communicate normally.

[0026] 3, with the loop antenna 1 of the first example, whether a = 25, a = 21, or a = 17, it can be seen that the offset amount at which the induced voltage is equal to or greater than the standard value (e.g., 1.5 V) is greater than that of the conventional loop antenna 100. For example, with the conventional loop antenna 100, the induced voltage becomes smaller than the standard value when the offset amount exceeds approximately 12 mm, but with the loop antenna 1 of the first example when a = 17, the induced voltage is equal to or greater than the standard value even when the offset amount is approximately 15 mm.

[0027] Furthermore, with respect to the loop antenna 1 of the first example, when the offset amount is approximately 13 mm or less, the induced voltage tends to increase as the value of a increases, whereas when the offset amount is greater than approximately 13 mm, the induced voltage tends to decrease as the value of a increases. Since the ideal characteristic is one that can maintain an induced voltage equal to or greater than the standard value even when the offset amount increases, the characteristics when a = 17, i.e., when the distance between the first portion 11 and the third portion 21 and the distance between the second portion 12 and the fourth portion 22 are 8 mm, are the best among a = 25, a = 21, and a = 17.

[0028] As described above, in the first example, the loop antenna 1 is formed so that the first loop portion 10 and the second loop portion 20 are shifted in the first direction, thereby suppressing the decrease in induced voltage due to positional shift with the opposing loop antenna.

[0029] Next, a second example will be described.

[0030] 4 is a front perspective view showing a second example of the loop antenna 1 according to the embodiment. The following description will focus on the differences from the first example.

[0031] The multiple loop portions include a first loop portion 10, a second loop portion 20, and a third loop portion 30. In the loop antenna 1 of the second example, the multiple loop portions are three loop portions: the first loop portion 10, the second loop portion 20, and the third loop portion 30. In other words, the first loop portion 10, the second loop portion 20, and the third loop portion 30 are formed by a single pattern.

[0032] One pattern is configured in the order of the first loop portion 10, the second loop portion 20, and the third loop portion 30 from one end A to the other end B. Specifically, the first loop portion 10 and the second loop portion 20 are continuous, and the second loop portion 20 and the third loop portion 30 are continuous, with one end of the first loop portion 10 being one end A and the other end of the first loop portion 10 being one end of the second loop portion 20. Furthermore, the other end of the second loop portion 20 is one end of the third loop portion 30, and the other end of the third loop portion 30 is the other end B. For convenience, the boundaries between the first loop portion 10 and the second loop portion 20 are referred to as the other end of the first loop portion 10 and one end of the second loop portion 20, but in reality, the boundaries between the first loop portion 10 and the second loop portion 20 are not visible. Similarly, the boundary between the second loop portion 20 and the third loop portion 30 is referred to as the other end of the second loop portion 20 and one end of the third loop portion 30, but in reality, the boundary between the second loop portion 20 and the third loop portion 30 is not visibly defined.

[0033] The first loop portion 10 has a first portion 11 and a second portion 12 that face each other in a first direction. In the second example, the first direction is the left-right direction on the paper surface of FIG. 4 . Because each of the multiple loop portions has a rectangular shape, the first portion 11 and the second portion 12 are sides that face each other in the first direction. The first portion 11 constitutes the one end A side of the first loop portion 10 relative to the second portion 12 (i.e., the one end side of the first loop portion 10).

[0034] The second loop portion 20 has a third portion 21 and a fourth portion 22 that face each other in the first direction. Since each of the multiple loop portions has a rectangular shape, the third portion 21 and the fourth portion 22 are sides that face each other in the first direction. The third portion 21 constitutes the second loop portion 20 closer to one end A than the fourth portion 22 (i.e., closer to one end of the second loop portion 20).

[0035] The second loop portion 20 has a fifth portion 23 and a sixth portion 24 that face each other in a second direction that intersects with the first direction. In the second example, the second direction is the vertical direction on the paper surface of FIG. 4 . Because each of the multiple loop portions has a rectangular shape, the fifth portion 23 and the sixth portion 24 are opposite sides in the second direction. The fifth portion 23 constitutes the one end A side of the second loop portion 20 relative to the sixth portion 24 (i.e., the one end side of the second loop portion 20). The fifth portion 23 also constitutes the one end A side of the second loop portion 20 relative to the third portion 21. The third portion 21 also constitutes the one end A side of the second loop portion 20 relative to the sixth portion 24. The sixth portion 24 also constitutes the one end A side of the second loop portion 20 relative to the fourth portion 22.

[0036] The third loop portion 30 has a seventh portion 31 and an eighth portion 32 that face each other in the second direction. Because each of the multiple loop portions has a rectangular shape, the seventh portion 31 and the eighth portion 32 are sides that face each other in the second direction. The seventh portion 31 constitutes the third loop portion 30 closer to one end A than the eighth portion 32 (i.e., closer to one end of the third loop portion 30).

[0037] When the substrate is viewed in a plane, the first portion 11, the second portion 12, the third portion 21, and the fourth portion 22 are arranged in the first direction in the order of first portion 11, third portion 21, second portion 12, fourth portion 22, as shown in Fig. 4. Specifically, when the substrate is viewed in a plane, the first portion 11, the second portion 12, the third portion 21, and the fourth portion 22 are arranged on a virtual line extending in the first direction in the order of first portion 11, third portion 21, second portion 12, fourth portion 22. When the substrate is viewed in a plane, the distance between the first portion 11 and the third portion 21 and the distance between the second portion 12 and the fourth portion 22 (i.e., the amount of deviation in the first direction) is greater than the pattern width of one of the patterns constituting the loop antenna 1. For example, the distance between the first portion 11 and the third portion 21 and the distance between the second portion 12 and the fourth portion 22 may be 5.5 mm or more, 7.5 mm or more, or 9.5 mm or more.

[0038] When the substrate is viewed in a plan view, the fifth portion 23, the sixth portion 24, the seventh portion 31, and the eighth portion 32 are arranged in the second direction in the order of the fifth portion 23, the seventh portion 31, the sixth portion 24, and the eighth portion 32. Specifically, when the substrate is viewed in a plan view, the fifth portion 23, the sixth portion 24, the seventh portion 31, and the eighth portion 32 are arranged on a virtual line extending in the second direction in the order of the fifth portion 23, the seventh portion 31, the sixth portion 24, and the eighth portion 32. When the substrate is viewed in a plan view, the distance between the fifth portion 23 and the seventh portion 31 and the distance between the sixth portion 24 and the eighth portion 32 (i.e., the amount of deviation in the second direction) is greater than the pattern width of one of the patterns constituting the loop antenna 1. For example, the distance between the fifth portion 23 and the seventh portion 31 and the distance between the sixth portion 24 and the eighth portion 32 may be 2 mm or more, 3 mm or more, or 4 mm or more.

[0039] The effects achieved by forming the loop antenna 1 so that the first part 11, the second part 12, the third part 21, and the fourth part 22 are arranged in the order of first part 11, third part 21, second part 12, fourth part 22 in the first direction, and the fifth part 23, sixth part 24, seventh part 31, and eighth part 32 are arranged in the order of fifth part 23, seventh part 31, sixth part 24, eighth part 32 in the second direction, i.e., so that the first loop part 10 and the second loop part 20 are shifted in the first direction and the second loop part 20 and the third loop part 30 are shifted in the second direction, will be explained in comparison with a conventional loop antenna 100.

[0040] For example, the vertical size (second direction) of the loop antenna 1 of the second example and the conventional loop antenna 100 is 33 mm, and the horizontal size (first direction) is 36 mm. Furthermore, the distance between the seventh portion 31 and the sixth portion 24 of the loop antenna 1 of the second example is a mm, and the distance between the third portion 21 and the second portion 12 is b mm. When b is fixed at 25, the effects were verified for a = 25, a = 21, and a = 17, and when a is fixed at 25, the effects were verified for b = 25, b = 21, and b = 17.

[0041] 5 and 6 are graphs showing the induced voltages for each offset amount generated in the opposing loop antenna by the loop antenna of the second example and the conventional example. Fig. 5 shows the verification results when b is fixed at 25, and Fig. 6 shows the verification results when a is fixed at 25.

[0042] 5 and 6, the horizontal axis represents the amount of deviation (called the offset) between the center of the loop antenna of the IC card and the center of the loop antenna 1 or 100, and the vertical axis represents the induced voltage generated in the loop antenna of the IC card. For example, the offset is the amount of deviation in the second direction. For example, here, the standard value for the induced voltage is 1.5 V, and it is assumed that when an induced voltage of 1.5 V or more is generated, the reader / writer and the IC card can communicate normally.

[0043] 5, with the loop antenna 1 of the second example, when b is fixed at 25, whether a = 25, a = 21, or a = 17, the offset amount at which the induced voltage is equal to or greater than the standard value (e.g., 1.5 V) is greater than that of the conventional loop antenna 100. For example, with the conventional loop antenna 100, the induced voltage becomes smaller than the standard value when the offset amount exceeds approximately 12 mm, but with the loop antenna 1 of the second example when a = 17, the induced voltage is equal to or greater than the standard value even when the offset amount is approximately 17 mm.

[0044] Furthermore, for the loop antenna 1 of the second example, when the offset amount is approximately 10 mm or less, the induced voltage tends to increase as the value of a increases, and when the offset amount is greater than approximately 10 mm, the induced voltage tends to decrease as the value of a increases. Since the ideal characteristic is one that can maintain an induced voltage above the standard value even when the offset amount is large, the best characteristic is obtained when the value of a is 17 out of the values ​​of a = 25, a = 21, and a = 17.

[0045] 6, with the loop antenna 1 of the second example, when a is fixed at 25, whether b is 25, b is 21, or b is 17, the offset amount at which the induced voltage exceeds the standard value (e.g., 1.5 V) is larger than that of the conventional loop antenna 100. Furthermore, with respect to the loop antenna 1 of the second example, since the induced voltage tends to increase as b increases, the characteristics are best when b is 25 out of b=25, b=21, and b=17.

[0046] As described above, in the second example, the loop antenna 1 is formed so that the first loop portion 10 and the second loop portion 20 are shifted in the first direction, and the second loop portion 20 and the third loop portion 30 are shifted in the second direction, thereby further suppressing the decrease in induced voltage due to misalignment with the opposing loop antenna.

[0047] Next, a third and fourth example will be described.

[0048] 7 is a front perspective view showing a third example of the loop antenna 1 according to the embodiment. The following description will focus on the differences from the first example.

[0049] The multiple loop portions include a first loop portion 10 and a second loop portion 20. In the loop antenna 1 of the third example, the multiple loop portions are three loop portions: the first loop portion 10, the fourth loop portion 40, and the second loop portion 20. In other words, the first loop portion 10, the fourth loop portion 40, and the second loop portion 20 are formed by a single pattern.

[0050] One pattern is configured in the order of the first loop portion 10, the fourth loop portion 40, and the second loop portion 20 from one end A to the other end B. Specifically, the first loop portion 10 and the fourth loop portion 40 are continuous, and the fourth loop portion 40 and the second loop portion 20 are continuous, with one end of the first loop portion 10 being one end A and the other end of the first loop portion 10 being one end of the fourth loop portion 40. Furthermore, the other end of the fourth loop portion 40 is one end of the second loop portion 20, and the other end of the second loop portion 20 is the other end B. For convenience, the boundaries between the first loop portion 10 and the fourth loop portion 40 are referred to as the other end of the first loop portion 10 and the one end of the fourth loop portion 40, but in reality, the boundaries between the first loop portion 10 and the fourth loop portion 40 are not visible. Similarly, the boundary between the fourth loop portion 40 and the second loop portion 20 is referred to as the other end of the fourth loop portion 40 and one end of the second loop portion 20, but in reality, the boundary between the fourth loop portion 40 and the second loop portion 20 is not visibly defined.

[0051] In the loop antenna 1 of the first example, the first loop portion 10 and the second loop portion 20 are continuous, but as in the loop antenna 1 of the third example, the first loop portion 10 and the second loop portion 20 do not have to be continuous, and another loop portion such as the fourth loop portion 40 may be provided between them. Even if another loop portion is provided between the first loop portion 10 and the second loop portion 20, when focusing on the first loop 10 and the second loop portion 20, one pattern will be configured in the order of the first loop portion 10 and the second loop portion 20 from one end A to the other end B.

[0052] Regarding the first part 11 and the second part 12 of the first loop section 10 and the third part 21 and the fourth part 22 of the second loop section 20 in the third example loop antenna 1, they are basically in the same positional relationship as those in the first example loop antenna 1, so explanations will be omitted.

[0053] FIG. 8 is a front perspective view showing a fourth example of the loop antenna 1 according to the embodiment.

[0054] The multiple loop portions include a first loop portion 10, a second loop portion 20, and a third loop portion 30. The loop antenna 1 of the fourth example has a different shape from the loop antenna 1 of the second example, but the positional relationships between the first portion 11 and the second portion 12 of the first loop portion 10, the third portion 21, the fourth portion 22, the fifth portion 23, and the sixth portion of the second loop portion 20, and the seventh portion 31 and the eighth portion 32 of the third loop portion 30 are basically the same as those in the loop antenna 1 of the second example, and therefore will not be described again.

[0055] The magnetic field strength of the third example, the fourth example, and the conventional loop antenna will be explained using FIG. 9, and the induced voltage generated in the opposing loop antenna by the third example, the fourth example, and the conventional loop antenna will be explained using FIG. 10.

[0056] Fig. 9 is a graph showing the magnetic field strength of the third example, the fourth example, and the conventional loop antenna. The horizontal axis of Fig. 9 represents the distance in the left-right direction on the paper of Figs. 2, 7, and 8, with 26 mm corresponding to the center of the third example, the fourth example, and the conventional loop antenna. Fig. 9 is a graph showing the magnetic field strength on a line in the left-right direction on the paper at a position offset by 15 mm (i.e., a position shifted 15 mm in the vertical direction on the paper from the center of each loop antenna in Figs. 2, 7, and 8).

[0057] As shown in Figure 9, the magnetic field strength at the 26 mm position of the conventional loop antenna 100 is 3.16 A / m, the magnetic field strength at the 26 mm position of the loop antenna 1 of the third example is 6.81 A / m, and the magnetic field strength at the 26 mm position of the loop antenna 1 of the fourth example is 6.47 A / m.

[0058] FIG. 10 is a graph showing the induced voltages for each offset amount that are generated in the counterpart loop antenna by the loop antennas of the third example, the fourth example, and the conventional example.

[0059] 10, the horizontal axis represents the amount of deviation (called the offset) between the center of the IC card's loop antenna and the center of loop antenna 1, and the vertical axis represents the induced voltage generated in the IC card's loop antenna. For example, the offset is the amount of deviation in the first direction (vertical direction) in the third example, and the amount of deviation in the second direction (vertical direction) in the fourth example. For example, the standard value for the induced voltage is 1.5 V, and it is assumed that when an induced voltage of 1.5 V or more is generated, the reader / writer and IC card can communicate normally.

[0060] As shown in Fig. 9, it can be seen that the loop antennas 1 of the third and fourth examples have a stronger magnetic field strength at the center than the conventional loop antenna 100. Also, as shown in Fig. 10, it can be seen that the loop antennas 1 of the third and fourth examples can tolerate a larger offset amount than the conventional loop antenna 100. Furthermore, it can be seen that the loop antenna 1 of the fourth example, in which the first loop portion 10 and the second loop portion 20 are offset in the first direction and the second loop portion 20 and the third loop portion 30 are offset in the second direction, can tolerate a larger offset amount than the loop antenna 1 of the third example, in which the first loop portion 10 and the second loop portion 20 are offset in the first direction.

[0061] While the loop antenna 1 of the present disclosure has been described above based on the embodiments, the present disclosure is not limited to the above-described embodiments. As long as they do not deviate from the spirit of the present disclosure, various modifications conceivable by those skilled in the art to the present embodiments and configurations constructed by combining components of different embodiments are also included within the scope of the present disclosure.

[0062] For example, in the above embodiment, an example was described in which the loop antenna 1 is provided in a reader / writer and the communication partner is an IC card, but the loop antenna 1 may also be provided in a notebook PC (Personal Computer) or a smartphone, and the communication partner is not limited to an IC card but may also be an IC tag, etc.

[0063] For example, in the above embodiment, the loop portions each have a rectangular shape, but they may also have a circular shape.

[0064] For example, in the above embodiment, the substrate on which the loop antenna 1 is provided is a double-sided substrate, but it may be a multi-layer substrate.

[0065] In addition, this disclosure also includes forms obtained by making various modifications to the embodiments that a person skilled in the art would think of, and forms realized by arbitrarily combining the components and functions in each embodiment within the scope of the present disclosure.

[0066] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0067] (Technology 1) A loop antenna provided on a substrate, wherein when a loop portion is a pattern that goes around once around an arbitrary point on the substrate, the loop antenna has a plurality of the loop portions, the plurality of loop portions are formed by a single linear pattern, the plurality of loop portions include a first loop portion and a second loop portion, the single pattern is configured in the order of the first loop portion and the second loop portion from one end to the other end of the single pattern, the first loop portion has a first portion and a second portion that face each other in a first direction, the second loop portion has a third portion and a fourth portion that face each other in the first direction, and when the substrate is viewed in a plane, the first portion, the second portion, the third portion, and the fourth portion are arranged in the order of the first portion, the third portion, the second portion, and the fourth portion in the first direction.

[0068] In this way, by forming the loop antenna so that the first loop portion and the second loop portion are misaligned in the first direction, it is possible to suppress a decrease in induced voltage due to misalignment with the counterpart loop antenna.

[0069] (Technology 2) A loop antenna described in Technology 1, wherein the plurality of loop portions each have a rectangular shape, the first portion and the second portion are opposite sides in the first direction, and the third portion and the fourth portion are opposite sides in the first direction.

[0070] For example, the loop antenna of an IC card often has a rectangular shape, and if the multiple loop portions also have a rectangular shape like the loop antenna of the IC card, the induced voltage generated in the opposing loop antenna can be increased.

[0071] (Technology 3) A loop antenna described in Technology 1 or 2, wherein when the substrate is viewed in a plane, the distance between the first portion and the third portion and the distance between the second portion and the fourth portion are greater than the pattern width of the single pattern.

[0072] In this way, by making the amount of misalignment between the first loop portion and the second loop portion in the first direction larger than the pattern width, it is possible to suppress a decrease in induced voltage due to misalignment with the counterpart loop antenna.

[0073] (Technology 4) The loop antenna according to Technology 1, wherein the plurality of loop portions further include a third loop portion, the single pattern is configured in the order of the first loop portion, the second loop portion, and the third loop portion from one end of the single pattern to the other end, the second loop portion has a fifth portion and a sixth portion that face each other in a second direction that intersects with the first direction, the third loop portion has a seventh portion and an eighth portion that face each other in the second direction, and when the substrate is viewed in a plane, the fifth portion, the sixth portion, the seventh portion, and the eighth portion are arranged in the order of the fifth portion, the seventh portion, the sixth portion, and the eighth portion in the second direction.

[0074] In this way, by forming the loop antenna so that the first loop portion and the second loop portion are shifted in the first direction and the second loop portion and the third loop portion are shifted in the second direction, the decrease in induced voltage due to misalignment with the opposing loop antenna can be further suppressed.

[0075] (Technology 5) A loop antenna described in Technology 4, wherein the multiple loop portions each have a rectangular shape, the first portion and the second portion are opposite sides in the first direction, the third portion and the fourth portion are opposite sides in the first direction, the fifth portion and the sixth portion are opposite sides in the second direction, and the seventh portion and the eighth portion are opposite sides in the second direction.

[0076] For example, the loop antenna of an IC card often has a rectangular shape, and if the multiple loop portions also have a rectangular shape like the loop antenna of the IC card, the induced voltage generated in the opposing loop antenna can be increased.

[0077] (Technology 6) A loop antenna described in Technology 4 or 5, wherein, when the substrate is viewed in a plane, the distance between the first portion and the third portion, the distance between the second portion and the fourth portion, the distance between the fifth portion and the seventh portion, and the distance between the sixth portion and the eighth portion are greater than the pattern width of the single pattern.

[0078] In this way, the amount of deviation in the first direction between the first loop portion and the second loop portion is greater than the pattern width, and the amount of deviation in the second direction between the second loop portion and the third loop portion is greater than the pattern width, so that the decrease in induced voltage due to positional deviation with the opposing loop antenna can be suppressed.

[0079] The present disclosure can be applied to a reader / writer for communicating with an IC card.

[0080] 1, 100 Loop antenna 10 First loop portion 11 First portion 12 Second portion 20 Second loop portion 21 Third portion 22 Fourth portion 23 Fifth portion 24 Sixth portion 30 Third loop portion 31 Seventh portion 32 Eighth portion A One end B Other end

Claims

1. A loop antenna provided on a substrate, wherein when a loop portion is a pattern that goes around an arbitrary point on the substrate, the loop antenna has a plurality of the loop portions, the plurality of loop portions are formed by a single linear pattern, the plurality of loop portions include a first loop portion and a second loop portion, the single pattern is configured in the order of the first loop portion and the second loop portion from one end to the other end of the single pattern, the first loop portion has a first portion and a second portion that face each other in a first direction, the second loop portion has a third portion and a fourth portion that face each other in the first direction, and when the substrate is viewed in a plane, the first portion, the second portion, the third portion, and the fourth portion are arranged in the order of the first portion, the third portion, the second portion, and the fourth portion in the first direction.

2. The loop antenna as described in claim 1, wherein each of the multiple loop portions has a rectangular shape, the first portion and the second portion are opposite sides in the first direction, and the third portion and the fourth portion are opposite sides in the first direction.

3. The loop antenna as described in claim 1 or 2, wherein the distance between the first portion and the third portion and the distance between the second portion and the fourth portion when the substrate is viewed in a plan view are greater than the pattern width of the single pattern.

4. The loop antenna as described in claim 1, wherein the multiple loop portions further include a third loop portion, the single pattern is configured in the order of the first loop portion, the second loop portion, and the third loop portion from one end of the single pattern to the other end, the second loop portion has a fifth portion and a sixth portion facing each other in a second direction intersecting the first direction, the third loop portion has a seventh portion and an eighth portion facing each other in the second direction, and when the substrate is viewed in a plane, the fifth portion, the sixth portion, the seventh portion, and the eighth portion are arranged in the second direction in the order of the fifth portion, the seventh portion, the sixth portion, and the eighth portion.

5. A loop antenna as described in claim 4, wherein each of the multiple loop portions has a rectangular shape, the first portion and the second portion are opposite sides in the first direction, the third portion and the fourth portion are opposite sides in the first direction, the fifth portion and the sixth portion are opposite sides in the second direction, and the seventh portion and the eighth portion are opposite sides in the second direction.

6. A loop antenna as described in claim 4 or 5, wherein, when the substrate is viewed in a plan view, the distance between the first portion and the third portion, the distance between the second portion and the fourth portion, the distance between the fifth portion and the seventh portion, and the distance between the sixth portion and the eighth portion are greater than the pattern width of the one pattern.

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