RF tag

Abstract

Increase the width of the frequency band in which RF tags can send and receive data. [Solution] The RF tag 1 has a plate-shaped substrate 11 made of a dielectric, a loop-shaped upper surface conductive pattern 12 formed on the upper surface of the plate-shaped substrate 11, a semiconductor device 15 provided between one end and the other end of the upper surface conductive pattern 12 and having a circuit for transmitting and receiving data stored in a memory by radio waves, a lower surface conductive pattern 13 formed on the lower surface of the plate-shaped substrate 11, and a connecting conductive pattern 14 connecting the upper surface conductive pattern 12 and the lower surface conductive pattern 13. The width in the short direction of the region inside the loop formed by the upper surface conductive pattern 12 is smaller than the width of the upper surface conductive pattern 12 in the short direction of the plate-shaped substrate 11 and the width of the upper surface conductive pattern 12 in the long direction of the plate-shaped substrate 11.

Description

[Technical Field]

[0001] The present invention relates to an RF tag. [Background technology]

[0002] BACKGROUND ART Conventionally, RF tags that are intended to be used in a state where they are attached to a conductor are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-61275 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, automatic adjustment devices have been used that have the function of automatically adjusting capacitance according to the frequency of radio waves received by RF tags. The RF tag described in Patent Document 1 is intended to be used while attached to a conductor, and is configured with an inverted-F antenna, which has low reactance, and the capacitance is increased by increasing the area of ​​the electrodes. As a result, even if the automatic adjustment device automatically adjusts the capacitance, there is a problem in that the adjustable range of the RF tag's frequency characteristics is narrow, and the width of the frequency band in which the RF tag can transmit and receive data is narrow.

[0005] The present invention has been made in view of these points, and has an object to widen the width of the frequency band in which an RF tag can transmit and receive data. [Means for solving the problem]

[0006] The RF tag of the present invention is an RF tag capable of transmitting and receiving data via radio waves, and comprises: a plate-shaped substrate formed from a dielectric; a loop-shaped upper surface conductive pattern formed on the upper surface of the plate-shaped substrate; a semiconductor device provided between one end and the other end of the upper surface conductive pattern, the semiconductor device storing the data and having a circuit for transmitting and receiving the data via radio waves; a lower surface conductive pattern formed on the lower surface of the plate-shaped substrate; and a connecting conductive pattern connecting the upper surface conductive pattern and the lower surface conductive pattern, wherein the width in the short direction of the region inside the loop formed by the upper surface conductive pattern is smaller than the width of the upper surface conductive pattern in the short direction of the plate-shaped substrate and the width of the upper surface conductive pattern in the long direction of the plate-shaped substrate.

[0007] The top surface conductive pattern may have a first region extending in a first direction, a second region extending parallel to the first region, a third region extending in a second direction perpendicular to the first direction, one end connected to the first region and the other end connected to the second region, and a fourth region extending parallel to the third region, one end connected to the side of the first region opposite to the side to which the third region is connected and the other end connected to the side of the second region opposite to the side to which the third region is connected, the first region having a first sub-region having one end connected to the third region and the other end connected to the semiconductor device, and a second sub-region having one end connected to the fourth region and the other end connected to the semiconductor device, and the connecting conductive pattern may have a region extending in the first direction, connected to the first sub-region at a position on a straight line in the first direction that passes through the first sub-region, the semiconductor device, and the second sub-region.

[0008] The connecting conductive pattern may have a first direction region extending in the first direction from a position connected to the first sub-region, and a second direction region connected to the first direction region and extending in the second direction.

[0009] The relationship between the area of ​​the smallest quadrangle including the top surface conductive pattern and the area of ​​the bottom surface conductive pattern may be such that the difference between the resonant frequency at which the radio wave intensity is maximum when the RF tag is mounted on a non-conductor and the resonant frequency at which the radio wave intensity is maximum when the RF tag is mounted on a conductor is smaller than the frequency bandwidth required to ensure the communication distance required for the RF tag.

[0010] Of the four sides of the smallest rectangle including the top surface conductive pattern, the positions of three sides other than the side to which the connecting conductive pattern is connected correspond to the positions of three sides of the four sides of the bottom surface conductive pattern other than the side to which the connecting conductive pattern is connected, and a difference in a first direction among the directions of the four sides of the rectangle between the position of a side of the rectangle in a second direction perpendicular to the first direction and the position of a side of the four sides of the bottom surface conductive pattern in the second direction may be within ±10% of the length in the first direction, and a difference in the second direction between the position of a side of the rectangle in the first direction among the four sides of the rectangle and the position of a side of the bottom surface conductive pattern in the first direction may be within ±10% of the length in the second direction.

[0011] The upper surface conductive pattern may have a first region extending in a first direction, a second region extending parallel to the first region, a third region extending in a second direction perpendicular to the first direction, one end connected to the first region and the other end connected to the second region, and a fourth region extending parallel to the third region, one end connected to the side of the first region opposite to the side to which the third region is connected and the other end connected to the side of the second region opposite to the side to which the third region is connected, the first region having a first sub-region having one end connected to the third region and the other end connected to the semiconductor device, and a second sub-region having one end connected to the fourth region and the other end connected to the semiconductor device, and a ratio of the smallest width to the largest width among the width of the first region in the short direction of the first region, the width of the second region in the short direction of the second region, the width of the third region in the short direction of the third region, and the width of the fourth region in the short direction of the fourth region may be 2 or less.

[0012] The area of ​​the upper surface conductive pattern may be 50% or more of the area of ​​the lower surface conductive pattern. [Effects of the Invention]

[0013] The present invention has the effect of widening the width of the frequency band in which an RF tag can transmit and receive data. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram for explaining an overview of an RF tag 1. [Figure 2] 1 is a diagram showing the configuration of an RF tag 1. FIG. [Figure 3] 10 is a diagram for explaining the width of the upper surface conductive pattern 12. FIG. [Figure 4] FIG. 10 is a diagram for explaining the position of a connecting conductive pattern 14. [Figure 5] 10 is a diagram for explaining the relationship between the shape of the upper surface conductive pattern 12 and the shape of the lower surface conductive pattern 13. FIG. [Figure 6] 10A and 10B are diagrams for explaining the configuration of a connecting conductive pattern 14. FIG. [Figure 7] 10 is a diagram showing another example of the configuration of the RF tag 1. FIG. [Figure 8] FIG. 2 is a diagram showing frequency characteristics of the plate-shaped substrate 11 according to the present embodiment and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0015] [RF tag 1 overview] FIG. 1 is a diagram for explaining the outline of an RF tag 1. The RF tag 1 is a device capable of transmitting and receiving data via radio waves. When attached to a conductor 2, the RF tag 1 operates using power generated by receiving radio waves W1 transmitted from a reader / writer 3. The RF tag 1 emits radio waves W2 onto which data stored in a built-in semiconductor device is superimposed.

[0016] The conductor 2 is an object that can pass an electric current, such as a metal. The conductor 2 is not limited to metal, but may be wood or resin that contains a substance that can pass an electric current. Furthermore, the thickness of the conductor 2 in the attachment direction of the RF tag 1 is optional, and it may be a metal foil that can pass an electric current.

[0017] Because the RF tag 1 and the conductor 2 are capacitively coupled, the radio waves W2 generated by the RF tag 1 are also radiated through the conductor 2. As a result, even if the reader / writer 3 is located in a position where it is difficult to receive the radio waves W2 radiated by the RF tag 1, the reader / writer 3 can receive the radio waves W2 through the conductor 2 and thereby obtain the data stored in the RF tag 1.

[0018] 2A and 2B are diagrams showing the configuration of the RF tag 1. Fig. 2A is a perspective view of the RF tag 1. Fig. 2B is a top view of the RF tag 1. Fig. 2C is a bottom view of the RF tag 1.

[0019] The RF tag 1 has a plate-shaped substrate 11 , an upper surface conductive pattern 12 , a lower surface conductive pattern 13 , a connecting conductive pattern 14 , and a semiconductor device 15 . The plate-shaped substrate 11 is made of a dielectric material. In the example shown in Fig. 2, the upper and lower surfaces of the plate-shaped substrate 11 are rectangular, but the shapes of the upper and lower surfaces of the plate-shaped substrate 11 may be polygonal, oval, or elliptical.

[0020] Furthermore, the dielectric constituting plate-shaped substrate 11 may be composed of multiple types of members. Plate-shaped substrate 11 may have a plate-shaped dielectric to which a sheet-shaped dielectric member is bonded, on which upper surface conductive patterns 12, lower surface conductive patterns 13, connecting conductive patterns 14, and semiconductor devices 15 are provided.

[0021] The upper surface conductive pattern 12 is a loop-shaped conductive pattern formed on the upper surface of the plate-shaped substrate 11. The plate-shaped substrate 11 is exposed inside the loop formed by the upper surface conductive pattern 12. Part of the loop formed by the upper surface conductive pattern 12 has an area where no conductive pattern is formed, and a semiconductor device 15 is provided in this area.

[0022] The lower surface conductive pattern 13 is a conductive pattern formed on the lower surface of the plate-shaped substrate 11. The lower surface conductive pattern 13 has, for example, a rectangular shape. The area of ​​the lower surface conductive pattern 13 is larger than the area of ​​the upper surface conductive pattern 12 and smaller than the area of ​​the lower surface of the plate-shaped substrate 11.

[0023] The connecting conductive pattern 14 is a conductive pattern that connects the top surface conductive pattern 12 and the bottom surface conductive pattern 13. The connecting conductive pattern 14 is configured to start from a partial region of the top surface conductive pattern 12, pass through the side surface of the plate-shaped substrate 11, and end at a partial region of the bottom surface conductive pattern 13. In the example shown in Fig. 2, the connecting conductive pattern 14 passes through one end of the top surface conductive pattern 12, the semiconductor device 15, and the other end of the top surface conductive pattern 12, and is connected to the top surface conductive pattern 12 at a position on a straight line parallel to the longitudinal direction of the plate-shaped substrate 11.

[0024] Fig. 4 is a diagram for explaining the position of the connecting conductive pattern 14. Fig. 4(a) is a diagram showing the top surface conductive pattern 12 in a state where the semiconductor device 15 is not provided on the RF tag 1. Fig. 4(a) shows one end T1 and the other end T2 of the top surface conductive pattern 12. Although convex portions are formed at the one end T1 and the other end T2 in the example shown in Fig. 4(a), convex portions do not necessarily have to be formed at the one end T1 and the other end T2.

[0025] As shown by the thick line in Fig. 4(b), the connecting conductive pattern 14 is connected to the top surface conductive pattern 12 at a position including a straight line L that passes through the rectangle including the semiconductor device 15 and is parallel to the longitudinal direction of the plate-like substrate 11. As long as the straight line L is included in the range where the connecting conductive pattern 14 and the top surface conductive pattern 12 are connected, the width of the connecting conductive pattern 14 may be larger or smaller than the width in the short direction of the region indicated by the thick line. Note that although the straight line L is drawn near the center of the region indicated by the thick line in Fig. 4(b), the position of the straight line L may be any position in the short direction of the region indicated by the thick line.

[0026] The semiconductor device 15 has a memory that stores data to be transmitted to the reader / writer 3. The semiconductor device 15 is provided between one end and the other end of the upper surface conductive pattern 12. Specifically, the semiconductor device 15 is provided between one end and the other end of the upper surface conductive pattern 12 in a region extending in the longitudinal direction of the plate-shaped substrate 11.

[0027] The semiconductor device 15 also has a circuit for transmitting and receiving data stored in the memory via radio waves. The semiconductor device 15 has multiple built-in capacitors, and can adjust the capacitance between one end and the other end of the top surface conductive pattern 12 by switching one or more capacitors connected between one end and the other end of the top surface conductive pattern 12. The semiconductor device 15 adjusts the capacitance so that the strength of the received radio waves is maximized, for example.

[0028] If the reactance of the RF tag 1 is L and the capacitance is C, the resonant frequency f is expressed as 1 / (2π√(LC)). In order to change the resonant frequency as much as possible by adjusting the capacitance of the semiconductor device 15, it is desirable to make the capacitance of the RF tag as small as possible when the semiconductor device 15 is not installed.

[0029] However, the frequency band of radio waves that allows the RF tag 1 to communicate with the reader / writer 3 is set within a predetermined range, so in order to reduce the capacitance of the RF tag 1, it is necessary to increase the reactance of the RF tag 1. Therefore, the RF tag 1 has various features to increase the reactance. The features of the RF tag 1 are explained below.

[0030] [Features of RF tag 1] FIG. 3 is a diagram illustrating the width of the top surface conductive pattern 12. The top surface conductive pattern 12 has a first region (12a in FIG. 3) extending in a first direction and a second region (12b in FIG. 3) extending parallel to the first region. The top surface conductive pattern 12 also has a third region (12c in FIG. 3) extending in a second direction perpendicular to the first direction, one end of which is connected to the first region and the other end of which is connected to the second region. The top surface conductive pattern 12 also has a fourth region (12d in FIG. 3) extending parallel to the third region, one end of which is connected to the first region on the side opposite to the side where the third region is connected and the other end of which is connected to the second region on the side opposite to the side where the third region is connected. In other words, the top surface conductive pattern 12 has first and second regions parallel to the longitudinal direction of the plate-shaped substrate 11, and third and fourth regions parallel to the lateral direction of the plate-shaped substrate 11.

[0031] The first region has a first sub-region 12a' having one end connected to the third region and the other end connected to the semiconductor device 15, and a second sub-region 12a'' having one end connected to the fourth region and the other end connected to the semiconductor device 15. The connecting conductive pattern 14 is connected to the first sub-region at a position on a straight line in the first direction that passes through the first sub-region, the semiconductor device 15, and the second sub-region, and has a region that extends in the first direction.

[0032] The width in the short-side direction of the region inside the loop formed by the upper surface conductive pattern 12 (E in Figure 3) is smaller than the width of the upper surface conductive pattern 12 in the long-side direction of the plate-shaped substrate 11 (A and B in Figure 3) and the width of the upper surface conductive pattern 12 in the short-side direction of the plate-shaped substrate 11 (C and D in Figure 3).

[0033] By providing top surface conductive pattern 12 with such a shape, the reactance of top surface conductive pattern 12 is sufficiently large, thereby enabling the capacitance at the resonant frequency to be reduced. As a result, by varying the capacitance of semiconductor device 15 within the adjustable range of the capacitance of semiconductor device 15, the resonant frequency can be adjusted over a wider frequency range than when the reactance of top surface conductive pattern 12 is small. As a result, RF tag 1 can transmit and receive data over a wider frequency band than conventional RF tags. Note that this frequency band is a frequency band in which data can be transmitted and received between RF tag 1 and reader / writer 3 at a required distance, and the width of this frequency band is, for example, 40 MHz.

[0034] The ratio of the smallest width to the largest width among the width of first region 12a in the short-side direction of first region 12a (A in FIG. 3), the width of second region 12b in the short-side direction of second region 12b (B in FIG. 3), the width of third region 12c in the short-side direction of third region 12c (C in FIG. 3), and the width of fourth region 12d in the short-side direction of fourth region 12d (D in FIG. 3) is not more than 2. When the ratio of the smallest width to the largest width in top surface conductive pattern 12 is not more than 2, it is possible to suppress an increase in capacitance caused by a decrease in current density in a wide region, and the effective loop area of ​​top surface conductive pattern 12 is increased.

[0035] 5A and 5B are diagrams for explaining the relationship between the shape of the upper surface conductive pattern 12 and the shape of the lower surface conductive pattern 13. Fig. 5(a) is a top view of the RF tag 1. The thick line in Fig. 5(a) indicates the outline of the smallest quadrilateral that includes the upper surface conductive pattern 12. Fig. 5(b) is a bottom view of the RF tag 1.

[0036] Of the four sides of the smallest quadrilateral including the upper surface conductive pattern 12, the positions of three sides (121a, 121b, 121c in Figure 5(a)) other than the side to which the connecting conductive pattern 14 is connected correspond to the positions of three sides (131a, 131b, 131c in Figure 5(b)) of the four sides of the lower surface conductive pattern 13 other than the side to which the connecting conductive pattern 14 is connected.

[0037] That is, side 121a is parallel to side 131a, and the distance from side 111a to side 121a in the longitudinal direction of plate-shaped substrate 11 is approximately equal to the distance from side 111a to side 131a. Side 121b is parallel to side 131b, and the distance from side 111b to side 121b in the lateral direction of plate-shaped substrate 11 is approximately equal to the distance from side 111b to side 131b. Side 121c is parallel to side 131c, and the distance from side 111c to side 121c in the longitudinal direction of plate-shaped substrate 11 is approximately equal to the distance from side 111c to side 131c.

[0038] Incidentally, since capacitance occurs between top surface conductive pattern 12 and bottom surface conductive pattern 13, the provision of bottom surface conductive pattern 13 suppresses fluctuations in capacitance due to the influence of conductor 2. However, if top surface conductive pattern 12 is attached to conductor 2 in a state where it protrudes significantly beyond bottom surface conductive pattern 13, the capacitance generated between the protruding area and conductor 2 will cause the resonant frequency to fluctuate downward.

[0039] If the amount of variation in the resonant frequency is large, depending on the characteristics of the conductor 2 on which the RF tag 1 is attached, the RF tag 1 may not resonate at a frequency that can ensure the communication distance required for the RF tag 1, and the RF tag 1 may not be able to transmit or receive data over that communication distance. Therefore, it is desirable that the relationship between the area of ​​the smallest quadrangle including the top surface conductive pattern 12 and the area of ​​the bottom surface conductive pattern 13 satisfy the condition that the difference between the resonant frequency f1 when the RF tag 1 has the highest resonant frequency and the resonant frequency f2 when the RF tag 1 has the lowest resonant frequency is smaller than the frequency bandwidth required to ensure the communication distance required for the RF tag 1.

[0040] As an example, the relationship between the area of ​​the smallest quadrangle including the top surface conductive pattern 12 and the area of ​​the bottom surface conductive pattern 13 desirably satisfies the condition that the difference between the resonant frequency f1 at which the radio wave intensity of the RF tag 1 is maximized when the RF tag 1 is mounted on a non-conductor (e.g., resin) and the resonant frequency f2 at which the radio wave intensity of the RF tag 1 is maximized when the RF tag 1 is mounted on a conductor (e.g., metal) is smaller than the frequency bandwidth required to ensure the communication distance required for the RF tag 1. With this relationship between the area of ​​the smallest quadrangle including the top surface conductive pattern 12 and the area of ​​the bottom surface conductive pattern 13, the required communication distance can be ensured regardless of the environment in which the RF tag 1 is used.

[0041] Specifically, the difference in the short-side direction of the plate-shaped substrate 11 between the position of side 121a in the long-side direction of the plate-shaped substrate 11, of the four sides of the smallest quadrangle including the top-surface conductive pattern 12, and the position of side 131a in the long-side direction of the plate-shaped substrate 11, of the four sides of the bottom-surface conductive pattern 13, is preferably within ±10% of the length of the short-side direction of the plate-shaped substrate 11. Similarly, the difference in the position of side 121c and the position of side 131c is preferably within ±10% of the length of the short-side direction of the plate-shaped substrate 11. Furthermore, the difference in the long-side direction of the plate-shaped substrate 11 between the position of side 121b in the short-side direction of the plate-shaped substrate 11, of the four sides of the quadrangle, and the position of side 131c in the short-side direction of the plate-shaped substrate 11, of the four sides of the bottom-surface conductive pattern 13, is preferably within ±10% of the length of the long-side direction of the plate-shaped substrate 11.

[0042] Furthermore, it is desirable that the area of ​​the upper surface conductive pattern 12 be 50% or more of the area of ​​the lower surface conductive pattern 13. By making the area of ​​the upper surface conductive pattern 12 50% or more of the area of ​​the lower surface conductive pattern 13 in this manner, the reactance of the upper surface conductive pattern 12 can be made sufficiently large.

[0043] Fig. 6 is a diagram for explaining the configuration of the connecting conductive pattern 14. Fig. 6(a) shows the same shape as the plate-like substrate 11 shown in Fig. 2(b), and Fig. 6(b) shows a modified example of the connecting conductive pattern 14.

[0044] 6(a) and 6(b), the connecting conductive pattern 14 has a first direction region 14a extending in a first direction from a position connected to the first sub-region 12a', and a second direction region 14b connected to the first direction region 14a and extending in a second direction. That is, the connecting conductive pattern 14 has a first direction region (14a in FIG. 6) extending in the longitudinal direction of the plate-shaped substrate 11 from a position connected to the top surface conductive pattern 12, and a second direction region (14b or 14d in FIG. 6) connected to the longitudinal direction region and extending in the lateral direction of the plate-shaped substrate 11. In this way, the connecting conductive pattern 14 has at least one bent portion where the direction of the pattern changes, but the number of bent portions the connecting conductive pattern 14 has is arbitrary.

[0045] 6(a), the connecting conductive pattern 14 may have two or more bent portions by further including a first direction region 14c connected to the second direction region 14b. By providing a bent portion in the connecting conductive pattern 14 in this way and changing the lengths of the regions before and after the bent portion, it is possible to easily design multiple types of plate-like substrates 11 with different reactances and capacitances according to the characteristics of the semiconductor device 15 mounted on the RF tag 1.

[0046] Fig. 7 is a diagram showing another example of the configuration of the RF tag 1. In the upper surface conductive pattern 12 of the RF tag 1 shown in Fig. 2, the semiconductor device 15 is provided at the center position of the first region 12a, but in the upper surface conductive pattern 12 of the RF tag 1 shown in Fig. 7, the semiconductor device 15 is provided at a position on the side farther from the connecting conductive pattern 14 than the center position of the first region 12a. In this way, the position in the longitudinal direction of the first region 12a where the semiconductor device 15 is provided is arbitrary.

[0047] [Frequency characteristics comparison] Fig. 8 is a diagram showing the frequency characteristics of the plate-shaped substrate 11 according to this embodiment and a comparative example. Fig. 8(a) shows the frequency characteristics of the plate-shaped substrate 11 shown in Fig. 2, and Fig. 8(b) shows the frequency characteristics of the RF tag of the comparative example. The horizontal axis of Fig. 8 represents the frequency, and the vertical axis represents the readable distance.

[0048] The plate-shaped substrate 11 corresponding to FIG. 8(a) has outer dimensions of 10 mm × 51 mm × 4.3 mm, and the areas of the upper and lower surfaces are 918 mm 2 Furthermore, the capacitance (electrostatic capacity) of the plate-shaped substrate 11 without the semiconductor device 15 was 2.95 pF, and the inductance was 10.2 nH.

[0049] The capacitance of the semiconductor device 15 was adjustable within a range of 0.16 pF, and the resonant frequency when the capacitance of the semiconductor device 15 was maximum was 24.7 MHz lower than the resonant frequency when the capacitance of the semiconductor device 15 was minimum. In other words, the adjustable range of the resonant frequency was 24.7 MHz. As a result, as shown in Figure 8(a), the bandwidth over which the readable distance was 10 m or more was approximately 40 MHz.

[0050] On the other hand, the RF tag of the comparative example corresponding to FIG. 8(b) has external dimensions of 14 mm × 55 mm × 2 mm, and the area of ​​the top and bottom surfaces is 770 mm 2 The capacitance of the RF tag was 6.86 pF and the inductance was 4.36 nH.

[0051] The RF tag of the comparative example has a smaller inductance and a larger capacitance than the plate-shaped substrate 11 of this embodiment, and therefore the adjustable range of the resonant frequency was 12.0 MHz, even though the IC device capable of adjusting capacitance was able to adjust the capacitance within a range of 0.18 pF. As a result, as shown in Figure 8(b), the bandwidth at which the readable distance is 10 m or more is approximately 15 MHz.

[0052] As described above, it has been confirmed that the plate-shaped substrate 11 of this embodiment has an inductance of 5 nH or more and a capacitance of 6 pF or less, and therefore can widen the frequency band of radio waves that allows the reader / writer 3 to read data from the RF tag at a specified distance compared to the RF tag of the comparative example.

[0053] [Effects of RF tag 1] As described above, in the RF tag 1, the width in the short-side direction of the region inside the loop formed by the top surface conductive pattern 12 is smaller than the width of the top surface conductive pattern 12 in the short-side direction of the plate-shaped substrate 11 and the width of the top surface conductive pattern 12 in the long-side direction of the plate-shaped substrate 11. Since the RF tag 1 has the top surface conductive pattern 12 with such a shape, the reactance of the RF tag 1 increases, and therefore, by adjusting the capacitance of the semiconductor device 15, it becomes possible to widen the width of the frequency band in which data can be transmitted and received to and from the reader / writer 3.

[0054] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments. [Explanation of symbols]

[0055] 1. RF tag 2 conductors 3 Reader / Writer 11 Plate-shaped substrate 12 Top surface conductive pattern 13 Bottom conductive pattern 14 Connecting conductive pattern 15 Semiconductor Devices

Claims

1. An RF tag capable of transmitting and receiving data by radio waves, a plate-shaped substrate formed of a dielectric material; a loop-shaped upper surface conductive pattern formed on the upper surface of the plate-shaped substrate; a semiconductor device provided between one end and the other end of the upper surface conductive pattern, the semiconductor device having a circuit for storing the data and transmitting and receiving the data by radio waves; a lower surface conductive pattern formed on the lower surface of the plate-shaped substrate; a connecting conductive pattern connecting the upper surface conductive pattern and the lower surface conductive pattern; It has The upper surface conductive pattern is a first region extending in a first direction; a second region extending parallel to the first region; a third region extending in a second direction perpendicular to the first direction, one end of which is connected to the first region and the other end of which is connected to the second region; a fourth region extending parallel to the third region, one end of which is connected to the first region on the side opposite to the side where the third region is connected, and the other end of which is connected to the second region on the side opposite to the side where the third region is connected, The first region is a first sub-region having one end connected to the third region and another end connected to the semiconductor device; a second sub-region having one end connected to the fourth region and the other end connected to the semiconductor device; and the connecting conductive pattern is connected to the first sub-region at a position on a straight line in the first direction that passes through the first sub-region, the semiconductor device, and the second sub-region, and has a region that extends in the first direction; RF tag.

2. The connecting conductive pattern is a first direction region extending in the first direction from a position connected to the first sub-region; a second direction region connected to the first direction region and extending in the second direction; having The RF tag according to claim 1.

3. An RF tag capable of transmitting and receiving data by radio waves, a plate-shaped substrate formed of a dielectric material; a loop-shaped upper surface conductive pattern formed on the upper surface of the plate-shaped substrate; a semiconductor device provided between one end and the other end of the upper surface conductive pattern, the semiconductor device having a circuit for storing the data and transmitting and receiving the data by radio waves; a lower surface conductive pattern formed on the lower surface of the plate-shaped substrate; a connecting conductive pattern connecting the upper surface conductive pattern and the lower surface conductive pattern; It has The relationship between the area of ​​the smallest quadrangle including the top surface conductive pattern and the area of ​​the bottom surface conductive pattern satisfies the condition that the difference between the resonant frequency at which the radio wave intensity is maximized when the RF tag is mounted on a non-conductor and the resonant frequency at which the radio wave intensity is maximized when the RF tag is mounted on a conductor is smaller than the frequency bandwidth required to ensure the communication distance required for the RF tag. RF tag.

4. positions of three of the four sides of a smallest rectangle including the top surface conductive pattern other than the side to which the connecting conductive pattern is connected correspond to positions of three of the four sides of the bottom surface conductive pattern other than the side to which the connecting conductive pattern is connected; a difference in a first direction among the directions of the four sides of the rectangle between a position of one of the four sides of the rectangle in a second direction orthogonal to the first direction and a position of one of the four sides of the lower surface conductive pattern in the second direction is within ±10% of the length in the first direction, and a difference in the second direction between a position of one of the four sides of the rectangle in the first direction and a position of one of the four sides of the lower surface conductive pattern in the first direction is within ±10% of the length in the second direction. The RF tag according to claim 3.

Images