Non-contact communication devices

Abstract

To provide a non-contact communication device that suppresses unwanted radiation. [Solution] In the contactless communication device 10, a coil-shaped antenna pattern A is formed on the second surface of the substrate P, a first ground pattern G1 is formed along the periphery of the first surface of the substrate, and a second ground pattern G2 is formed in the air core of the antenna pattern and is connected to the first ground pattern by a ground connection wiring section 6. The first wiring section connects the output terminal 5a of the IC chip 5 to the starting end of the antenna pattern. The second wiring section 2 has a capacitor C and connects the first wiring section to the first ground pattern or the second ground pattern. The third wiring section 3 connects the first ground pattern or the second ground pattern to the ground terminal 5b. The area enclosed by the return path passing through the first wiring section, the second wiring section, the first ground pattern or the second ground pattern and the third wiring section is 25% or less of the first surface.

Description

[[Technical Field]]

[0001] The present technology relates to, for example, a non-contact communication device that performs non-contact wireless communication with another device such as a reader / writer. [[Background Art]]

[0002] In recent years, transportation cards, electronic money cards, credit cards, smartphones and the like are equipped with non-contact wireless communication devices using RFID (Radio Frequency IDentification) technology (see, for example, Patent Document 1 below).

[0003] This type of non-contact wireless communication device generally includes a control unit, a coil-shaped antenna pattern, and the like. The non-contact wireless communication device utilizes an output from another device such as a reader / writer to perform electromagnetic induction via the antenna pattern and generate necessary electric power. Then, the control unit performs necessary processing using this electric power and performs non-contact wireless communication with another device such as a reader / writer via the antenna pattern. [[Prior Art Documents]] [[Patent Documents]]

[0004] [[Patent Document 1]] Japanese Unexamined Patent Application Publication No. 2015-65649 [[Summary of the Invention]] [[Problem to be Solved by the Invention]]

[0005] There is a problem that unnecessary radiation increases in non-contact wireless communication devices.

[0006] In view of the foregoing circumstances, an object of the present technology is to provide a non-contact communication device capable of suppressing unnecessary radiation. [[Means for Solving the Problem]]

[0007] The contactless communication device relating to this technology comprises a substrate, semiconductor components, an antenna pattern, a first ground pattern, a second ground pattern, a first wiring section, a second wiring section, a third wiring section, and a return path. The substrate has a first surface and a second surface opposite to the first surface. The semiconductor component has an output terminal and a ground terminal and is mounted on the first surface. The antenna pattern has a starting end which is the outer circumference end and a ending end which is the inner circumference end, and is a coil-shaped pattern formed on the second surface. The first ground pattern is formed along the periphery of the first surface. The second ground pattern is formed in the air core portion of the antenna pattern on the second surface and is connected to the first ground pattern. The first wiring section connects the output terminal and the starting end. The second wiring section has a capacitor and connects the first wiring section to the first ground pattern or the second ground pattern. The third wiring section connects the first ground pattern or the second ground pattern to the ground terminal. The return path is a return path that passes through the first wiring section, the second wiring section, the first ground pattern or the second ground pattern, and the third wiring section, and the area of ​​the portion enclosed by the path is 25% or less of the area of ​​the first surface.

[0008] This shortens the return path, thus suppressing unwanted radiation.

[0009] In the above-described contactless communication device, the second wiring section may connect the first wiring section to the ground pattern of the first ground pattern and the second ground pattern that is connected to the ground terminal via the third wiring section.

[0010] In the above-described contactless communication device, the second wiring section may connect the first wiring section to the ground pattern of the first ground pattern and the second ground pattern that is not connected to the ground terminal via the third wiring section.

[0011] In the above-described contactless communication device, the second wiring section may connect the first wiring section to the second ground pattern, and the third wiring section may connect the second ground pattern to the ground terminal.

[0012] In the above-described contactless communication device, the second wiring section may connect the first wiring section to the first ground pattern, and the third wiring section may connect the first ground pattern to the ground terminal.

[0013] In the above-described contactless communication device, the first ground pattern may have a broken portion in which a part of it is broken, and the second wiring portion may be connected to a location corresponding to the end of the first ground pattern formed by the broken portion.

[0014] In the above-described contactless communication device, the second wiring section connects the first wiring section and the first ground pattern, the third wiring section connects the second ground pattern and the ground terminal, and the contactless communication device may further include a fourth wiring section that connects the first ground pattern and the third wiring section.

[0015] In the above-described contactless communication device, the first ground pattern may have a first fractured portion in which a part of it is broken, a second fractured portion in which another part is broken, and an isolated region formed between the first fractured portion and the second fractured portion.

[0016] In the non-contact communication device described above, the second wiring portion may connect between the first wiring portion and the enclave region of the first ground pattern, and the fourth wiring portion may connect between the enclave region of the first ground pattern and the third wiring portion.

[0017] In the non-contact communication device described above, an area of a region enclosed by the return path may be 20% or less of an area of the first surface.

[0018] In the non-contact communication device described above, an area of a region enclosed by the return path may be 15% or less of an area of the first surface.

[0019] In the non-contact communication device described above, an area of a region enclosed by the return path may be 10% or less of an area of the first surface.

[0020] In the non-contact communication device described above, an area of a region enclosed by the return path may be 5% or less of an area of the first surface. [Effects of the Invention]

[0021] As described above, according to the present technology, it is possible to provide a non-contact communication device capable of suppressing unnecessary radiation. [Brief Description of Drawings]

[0022] [Figure 1] FIG. 1 is a plan view of the non-contact communication device according to the first embodiment of the present technology viewed from the front side. [Figure 2] FIG. 2 is a diagram for explaining the basic idea of the present technology. [Figure 3] FIG. 3 is a diagram for explaining the basic idea of the present technology. [Figure 4] FIG. 4 is a diagram showing a non-contact communication device according to a first comparative example. [Figure 5] FIG. 5 is a diagram showing measurement results of unnecessary radiation in the non-contact communication device according to the first comparative example. [Figure 6] This figure shows the measurement results of unwanted radiation in a non-contact communication device according to the first embodiment of this technology. [Figure 7] This is a plan view of a contactless communication device according to a second embodiment of this technology, as seen from the front side. [Figure 8] This figure shows a contactless communication device relating to the second comparative example. [Figure 9] This is a plan view of a contactless communication device according to a third embodiment of this technology, as seen from the front side. [Modes for carrying out the invention]

[0023] The embodiments of this technology will be described below with reference to the drawings.

[0024] ≪First Embodiment≫ <Overall structure and structure of each part> Figure 1 is a plan view of the contactless communication device 10 according to the first embodiment of this technology, as seen from the front side. In Figure 1, the components located on the back surface of the contactless communication device 10 are also shown transparently (similarly in Figures 4, 7 to 9 described later).

[0025] This contactless communication device 10 is a contactless wireless communication device that uses RFID technology to communicate with other devices, such as reader / writers, without physical contact, for example, in the 13.56 MHz frequency band. This contactless communication device 10 can be installed in, for example, transportation cards, electronic money cards, credit cards, smartphones, etc., but it can be installed in any device that is intended to communicate with other devices without physical contact.

[0026] As shown in Figure 1, the contactless communication device 10 has a thin, plate-shaped substrate P (printed wiring board P) that has a rectangular shape in plan view. In the example shown in Figure 1, the shape of the substrate P in plan view is rectangular, but the shape of the substrate P is not particularly limited and may be a polygon other than a rectangle, a circle, etc. The substrate P has a front surface (first surface) and a back surface (second surface) opposite to the front surface.

[0027] "The structure of the reverse side" In describing this embodiment, we will first explain the configuration of the back surface of the substrate P, which is shown transparently in Figure 1.

[0028] The contactless communication device 10 has a coil-shaped antenna pattern A and a plane-shaped second ground pattern G2 located in the center of the substrate P on its back side.

[0029] Antenna pattern A serves two purposes: as a communication antenna and as a power source generated by electromagnetic induction. This antenna pattern A is configured in a spiral shape, with its diameter gradually decreasing from the outer circumference to the inner circumference.

[0030] Antenna pattern A has its starting point at one of the four corners on the outer periphery of substrate P (the upper left corner in Figure 1), and its ending point on the inner periphery of substrate P. The central part of antenna pattern A is an empty space where antenna pattern A does not exist.

[0031] The second ground pattern G2 is located in the air core of antenna pattern A and is electrically connected to the termination of antenna pattern A. In the example shown in Figure 1, the second ground pattern G2 has a rectangular shape in plan view. However, the shape of the second ground pattern G2 is not limited to a rectangle; it may be a polygon or circular shape, etc.

[0032] "Surface composition" Next, the surface configuration of the substrate P will be described. The contactless communication device 10 has a strip-shaped first ground pattern G1 formed along the outer edge of the substrate P on its surface side. The contactless communication device 10 also has various electronic components that constitute the control unit of the contactless communication device 10, as well as various necessary wirings, etc., on its surface side.

[0033] The first ground pattern G1 is formed in a narrow strip shape and is provided on the surface side of the substrate P so as to encircle the outer edge of the substrate P. The first ground pattern G1 is electrically connected to the second ground pattern G2 via a ground connection wiring section 6.

[0034] The ground connection wiring section 6 is formed on the surface side of the substrate P and connects the first ground pattern G1 and the second ground pattern G2. Specifically, one end of the ground connection wiring section 6 is connected to the first ground pattern G1, and the other end is connected to the second ground pattern G2 via a hole (e.g., a via) that penetrates the substrate P in the vertical direction.

[0035] The various electronic components and necessary wiring that constitute the control unit of the contactless communication device 10 are arranged in the area enclosed by the first ground pattern G1. In the example shown in Figure 1, only the electronic components and wiring necessary to explain this technology are shown among the various electronic components and necessary wiring that constitute the control unit, and the other parts are omitted from the illustration. In other words, in reality, many electronic components and wiring other than those shown are provided on the surface of the substrate P.

[0036] As an electronic component constituting the control unit, a communication IC (Integrated Circuit) chip 5 (semiconductor component) is provided on the surface side of the substrate P. This IC chip 5 performs the processing necessary for communication with other devices such as a reader / writer, and performs contactless communication with other devices via the antenna pattern A.

[0037] The IC chip 5 has multiple terminals, including an output terminal 5a that outputs a signal (output waveform) for communication and a ground terminal 5b that is connected to ground.

[0038] One end of the first wiring section 1 is connected to the output terminal 5a of the IC chip 5. The first wiring section 1 is provided on the surface side of the substrate P and connects the output terminal 5a of the IC chip 5 to the starting end of the antenna pattern A. Specifically, one end of the first wiring section 1 is connected to the output terminal 5a of the IC chip 5, and the other end is connected to the starting end of the antenna pattern A through a hole (for example, a via) that penetrates the substrate P in the vertical direction.

[0039] A second wiring section 2 is connected to the first wiring section 1, branching off from it. The second wiring section 2 is located on the surface side of the substrate P and connects the first wiring section 1 to the second ground pattern G2 (the ground pattern of the first ground pattern G1 and the second ground pattern G2 that is connected to the ground terminal 5b of the IC chip 5 via the third wiring section 3). Specifically, one end of the second wiring section 2 is connected to an intermediate position on the first wiring section 1, and the other end is connected to the second ground pattern G2 via a hole (e.g., a via) that penetrates the substrate P in the vertical direction.

[0040] A capacitor C is provided in the second wiring section 2. This capacitor C is used to cut out unwanted high-frequency components from the signal output from the output terminal 5a of the IC chip 5.

[0041] Furthermore, one end of the third wiring section 3 is connected to the ground terminal 5b of the IC chip 5. The third wiring section 3 is provided on the surface side of the substrate P and connects the ground terminal 5b of the IC chip 5 to the second ground pattern G2. Specifically, one end of the third wiring section 3 is connected to the ground terminal 5b of the IC chip 5, and the other end is connected to the second ground pattern G2 via a hole (for example, a via) that penetrates the substrate P vertically.

[0042] In this embodiment, a portion of the output (current) from the output terminal 5a of the IC chip 5 returns to the ground terminal 5b of the IC chip 5 via the various wiring sections. This forms a return path. Specifically, in the first embodiment, this return path passes through a portion of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, a portion of the second ground pattern G2 (see dashed line), and the third wiring section 3.

[0043] In Figure 1, the region downstream of capacitor C in the return path is shown by a dashed line. In this region downstream of capacitor C, extra high-frequency components are generated, which can cause unwanted radiation.

[0044] However, in this embodiment, the configuration of the return path is designed to make the return path as short as possible. Typically, the area enclosed by this return path is 25% or less of the area of ​​the surface (or back) of the substrate P (or the area enclosed by the first ground pattern G1). Alternatively, the area enclosed by the return path may be 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, etc., of the area of ​​the surface (or back) of the substrate P.

[0045] Furthermore, the smaller the ratio of the area due to the return path to the surface area of ​​the substrate P (or the area enclosed by the first ground pattern G1), the greater the effect of suppressing unwanted radiation. However, due to the arrangement of ground patterns G1 and G2, IC chip 5, wiring sections 1-3, etc., there are limits to how small this ratio can be.

[0046] <Basic Concepts and Functions of This Technology> Next, we will explain the basic concepts of this technology and then describe its operation. Figures 2 and 3 are diagrams illustrating the basic concepts of this technology.

[0047] In order to stabilize the antenna characteristics, it is common practice to separate antenna pattern A from the various electronic components and wiring that constitute the control unit. Furthermore, in order to avoid increasing the stray capacitance of the antenna, power supplies and a plane-shaped ground pattern cannot be placed on the back side of antenna pattern A.

[0048] Therefore, in the contactless communication device 40 shown in Figure 2, the antenna pattern A and the electronic components and wiring for the control unit are arranged separately on the same plane of the substrate P. However, this configuration, as shown in Figure 2, has the problem of being large in size.

[0049] To address this size issue, in the contactless communication device 50 shown in Figure 3, the antenna pattern A is arranged on the back side of the substrate P, while the electronic components for the control unit, wiring, etc., are arranged on the front side of the substrate P. In this case, a plain ground pattern G2 is placed in the air core at the center of the antenna pattern A, and a strip-shaped ground pattern G1 (in the example in Figure 3, it is a loop that goes all the way around, but it does not have to be a loop) is placed around the area where the electronic components for the control unit, wiring, etc., are arranged, thereby addressing the problem of stray capacitance.

[0050] Furthermore, the contactless communication device 10 according to this embodiment, like the contactless communication device 10 shown in Figure 3, can also resolve the issues of stray capacitance (no plane-shaped ground pattern G2, etc., is placed on the back side of the antenna pattern A) and size (the antenna pattern A and the control unit are separated on the back and front sides).

[0051] On the other hand, there is the problem of unwanted radiation in wireless communication. This problem of unwanted radiation will be explained with reference to the non-contact communication device 60 of the first comparative example. Figure 4 is a diagram showing the non-contact communication device 60 of the first comparative example.

[0052] The contactless communication device 60 according to the first comparative example and the contactless communication device 10 according to the first embodiment differ in the configuration of the second wiring section 2, but the other configurations are basically the same.

[0053] As shown in Figure 4, in the first comparative example, one end of the second wiring section 2 is connected to an intermediate position of the first wiring section 1, and the other end is connected to the first ground pattern G1 (in the first embodiment, the other end is connected to the second ground pattern G2).

[0054] Furthermore, the first comparative example has two return paths: a first return path and a second return path.

[0055] The first return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, the right side of the first ground pattern G1 (clockwise from the connection point with the second wiring section 2 to the connection point with the ground connection wiring section 6), the ground connection wiring section 6, a part of the second ground pattern G2 (see dashed line), and the third wiring section 3.

[0056] On the other hand, the second return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, the left side of the first ground pattern G1 (counterclockwise from the connection point with the second wiring section 2 to the connection point with the ground connection wiring section 6), the ground connection wiring section 6, a part of the second ground pattern G2 (see dashed line), and the third wiring section 3.

[0057] In Figure 4, the regions downstream of capacitor C in the first and second return paths are shown by dashed lines. In these regions downstream of capacitor C, extra high-frequency components are generated, which can cause unwanted radiation. This can lead to problems such as failing to meet the requirements of radio wave standards.

[0058] In the first comparative example, there are problems such as a long return path and, consequently, large amounts of unwanted radiation. Therefore, in this embodiment, the configuration of the return path is designed to make the return path as short as possible.

[0059] In the first comparative example, the area enclosed by the first return path is approximately 50% of the surface area of ​​substrate P, and the area enclosed by the second return path is also approximately 50% of the surface area of ​​substrate P. Therefore, the sum of the areas enclosed by the first return path and the areas enclosed by the second return path is approximately 100% of the surface area of ​​substrate P.

[0060] In contrast, in this embodiment, the area enclosed by this return path is set to 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, etc., relative to the surface (or back) area of ​​the substrate P. As a result, the return path is shortened, and excess high-frequency components can be suppressed, thereby suppressing unwanted radiation.

[0061] Figure 5 shows the measurement results of unwanted radiation in a non-contact communication device 60 according to the first comparative example. Figure 6 shows the measurement results of unwanted radiation in a non-contact communication device 10 according to the first embodiment of this technology.

[0062] In Figures 5 and 6, the horizontal axis represents the frequency [MHz] of unwanted radiation, and the vertical axis represents the noise level [dB(μV / m)] of unwanted radiation. As can be seen from the comparison of Figures 5 and 6, the non-contact communication device 10 according to the first embodiment shown in Figure 6 has a lower noise level of unwanted radiation in all frequency ranges compared to the non-contact communication device 60 according to the first comparative example shown in Figure 5. As a result, the non-contact communication device 10 according to the first embodiment can meet the standards of radio wave standards.

[0063] ≪Second Embodiment≫ Next, a contactless communication device 20 according to the second embodiment of this technology will be described. In the second embodiment and subsequent embodiments, the description of parts having the same functions and configurations as those of the first embodiment described above will be omitted or simplified.

[0064] Figure 7 is a plan view of the contactless communication device 20 according to the second embodiment of this technology, as seen from the front side. In Figure 7, the components located on the back surface of the contactless communication device 10 are also shown transparently.

[0065] In the description of the second embodiment, we will focus on the differences from the first embodiment described above.

[0066] In the first embodiment described above, the second wiring section 2 connected the first wiring section 1 and the second ground pattern G2. In contrast, in the second embodiment, the second wiring section 2 connects the first wiring section 1 and the first ground pattern G1 (the ground pattern of the first ground pattern G1 and the second ground pattern G2 that is connected to the ground terminal 5b of the IC chip 5 via the third wiring section 3). Specifically, one end of the second wiring section 2 is connected to an intermediate position of the first wiring section 1, and the other end is connected to the first ground pattern G1.

[0067] Furthermore, in the first embodiment described above, the third wiring section 3 connected the ground terminal 5b of the IC chip 5 to the second ground pattern G2. In contrast, in the second embodiment, the third wiring section 3 connects the ground terminal 5b of the IC chip 5 to the first ground pattern G1. Specifically, one end of the third wiring section 3 is connected to the ground terminal 5b of the IC chip 5, and the other end is connected to the first ground pattern G1.

[0068] In the second embodiment, the first ground pattern G1 has a fractured portion B in which a part of it is broken. In other words, in the second embodiment, unlike the first embodiment, the first ground pattern G1 is not configured to completely encircle the ground.

[0069] The break B in the first ground pattern G1 is located at a position corresponding to the connection point where the second wiring section 2 and the first ground pattern G1 are connected. Correspondingly, the other end of the second wiring section 2 is connected to a location corresponding to the end of the first ground pattern G1 formed by the break B.

[0070] In the second embodiment, the return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, a part of the first ground pattern G1 (see dashed line), and the third wiring section 3.

[0071] In Figure 7, the region downstream of capacitor C in the return path is shown by a dashed line. In this region downstream of capacitor C, extra high-frequency components are generated, which can cause unwanted radiation.

[0072] However, in the second embodiment as well, the area of ​​the region enclosed by the return path is typically 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, etc., of the area of ​​the surface (or back) of the substrate P (or the area enclosed by the first ground pattern G1).

[0073] Therefore, in the second embodiment, as in the first embodiment, the return path is shortened and excess high-frequency components can be suppressed, thus suppressing unwanted radiation. Consequently, the standards of radio wave specifications can be met.

[0074] Figure 8 shows a contactless communication device 70 according to the second comparative example. Unlike the contactless communication device 20 according to the second embodiment, the contactless communication device 70 according to the second comparative example does not have a break B in the first ground pattern G1. Also, unlike the second embodiment, in the second comparative example the third wiring section 3 connects the ground terminal 5b of the IC chip 5 and the first ground pattern G1. In other respects, the second comparative example is basically the same as the second embodiment.

[0075] In the second comparative example, since the fracture section B is not provided with respect to the first ground pattern G1, the return path becomes longer. The second comparative example has two return paths, the first return path and the second return path.

[0076] The first return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, a part of the first ground pattern G1 (clockwise from the connection point with the second wiring section 2 to the connection point with the ground connection wiring section 6), the ground connection wiring section 6, a part of the second ground pattern G2 (see dashed line), and the third wiring section 3.

[0077] Furthermore, the second return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, another part of the first ground pattern G1 (counterclockwise from the connection point with the second wiring section 2 to the connection point with the ground connection wiring section 6), the ground connection wiring section 6, a part of the second ground pattern G2 (see dashed line), and the third wiring section 3.

[0078] In Figure 8, the regions downstream of capacitor C in the first and second return paths are shown by dashed lines. In these regions downstream of capacitor C, extra high-frequency components are generated, which can cause unwanted radiation. This can lead to problems such as failing to meet the requirements of radio wave standards.

[0079] In the second comparative example, the area enclosed by the first return path is approximately 70% of the surface area of ​​substrate P, and the area enclosed by the second return path is approximately 30% of the surface area of ​​substrate P. Therefore, the sum of the areas enclosed by the first and second return paths is approximately 100% of the surface area of ​​substrate P.

[0080] In contrast, in the second embodiment, the area enclosed by this return path is set to 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, etc., relative to the surface (or back) area of ​​the substrate P. This shortens the return path and suppresses excess high-frequency components, thereby suppressing unwanted radiation.

[0081] ≪Third Embodiment≫ Next, a contactless communication device 30 according to a third embodiment of this technology will be described.

[0082] Figure 9 is a plan view of the contactless communication device 30 according to the third embodiment of this technology, as seen from the front side. In Figure 9, the components located on the back surface of the contactless communication device 10 are also shown transparently.

[0083] The description of the third embodiment will focus on the differences from the first embodiment (rather than the second embodiment).

[0084] In the first embodiment described above, the second wiring section 2 connected the first wiring section 1 and the second ground pattern G2. In contrast, in the third embodiment (similar to the second embodiment), the second wiring section 2 connects the first wiring section 1 and the first ground pattern G1 (the ground pattern of the first ground pattern G1 and the second ground pattern G2 that is not connected to the ground terminal 5b of the IC chip 5 via the third wiring section 3). Specifically, one end of the second wiring section 2 is connected to the first wiring section 1, and the other end is connected to the first ground pattern G1.

[0085] Furthermore, in the third embodiment, unlike the first embodiment (and the second embodiment), a fourth wiring section 4 is added. This fourth wiring section 4 connects the first ground pattern G1 and the third wiring section 3. Specifically, one end of the fourth wiring section 4 is connected to the first ground pattern G1, and the other end is connected to an intermediate position in the third wiring section 3.

[0086] Furthermore, in the third embodiment, unlike the first embodiment, the first ground pattern G1 is provided with two fractured portions B1 and B2. That is, the first ground pattern G1 has a first fractured portion B1 in which a part is fractured, and a second fractured portion B2 in which the other part is fractured. Therefore, in the third embodiment, unlike the first embodiment (and similar to the second embodiment), the first ground pattern G1 is not configured to completely encircle the entire surface.

[0087] The first break in the first ground pattern G1 is located at a position corresponding to the connection point where the second wiring section 2 and the first ground pattern G1 are connected. The second break in the first ground pattern G1 is located at a position corresponding to the connection point where the fourth wiring section 4 and the first ground pattern G1 are connected.

[0088] In the third embodiment, in the first ground pattern G1, an isolated region E is formed in the region between the first fracture B1 and the second fracture B2. This isolated region E is separated from the main part of the first ground pattern G1, but is connected to the second ground pattern G2 via the fourth wiring section 4 and a part of the third wiring section 3, and is therefore brought down to ground potential.

[0089] The second wiring section 2 connects the first wiring section and the isolated region E of the first ground pattern. Specifically, one end of the second wiring section 2 is connected to an intermediate position of the first wiring section 1, and the other end is connected to a location corresponding to one end of the isolated region E of the first ground pattern G1.

[0090] Furthermore, the fourth wiring section 4 connects the isolated region E of the first ground pattern G1 with the third wiring section 3. Specifically, one end of the fourth wiring section 4 is connected to a location corresponding to the other end of the isolated region E of the first ground pattern G1, and the other end is connected to an intermediate position of the third wiring section.

[0091] In the third embodiment, the return path is a path that passes through a part of the first wiring section 1 (from the connection point with the IC chip 5 to the connection point with the second wiring section 2), the second wiring section 2, the isolated region E of the first ground pattern G1 (see dashed line), the fourth wiring section 4, and a part of the third wiring section 3 (from the connection point with the fourth wiring section 4 to the connection point with the IC chip 5).

[0092] In Figure 9, the region downstream of capacitor C in the return path is shown by a dashed line. In this region downstream of capacitor C, extra high-frequency components are generated, which can cause unwanted radiation.

[0093] Here, in describing the operation of the third embodiment, we will refer to the contactless communication device 60 according to the first comparative example shown in Figure 4. If the first broken portion B1, the second broken portion B2 in the first ground pattern G1, and the fourth wiring portion 4 are omitted from the contactless communication device 30 according to the third embodiment, the contactless communication device 30 according to the third embodiment will have the same configuration as the contactless communication device 60 according to the first comparative example.

[0094] As described above, the contactless communication device 10 according to the first comparative example has two return paths: a first return path and a second return path. The sum of the area enclosed by the first return path and the area enclosed by the second return path is approximately 100% of the surface (or back) area of ​​the substrate P. Therefore, in the first comparative example, the return path is long, and consequently, unwanted radiation is large.

[0095] On the other hand, in the third embodiment, similar to the first embodiment (and the second embodiment), the area of ​​the region enclosed by the return path is typically 25% or less, 20% or less, 15% or less, 10% or less, 5% or less, 4% or less, 3% or less, etc., of the area of ​​the surface (or back surface) of the substrate P (or the area enclosed by the first ground pattern G1).

[0096] Therefore, in the third embodiment, as in the first embodiment (and the second embodiment), the return path is shortened, and excess high-frequency components can be suppressed, thus suppressing unwanted radiation. Consequently, the standards of radio wave regulations can be met. [Explanation of Symbols]

[0097] 1...First wiring section 2…Second wiring section 3…Third wiring section 4…Fourth wiring section 5…IC chip 6…Wiring section for ground connection 10, 20, 30…Contactless communication device A... Antenna pattern B...Fracture C... Capacitor E... Enclave G1...First ground pattern G2...Second ground pattern P...Substrate

Claims

1. A substrate having a first surface and a second surface opposite to the first surface, A semiconductor component having an output terminal and a ground terminal, mounted on the first surface, A coil-shaped antenna pattern formed on the second surface has a starting end which is the outer peripheral end and a terminal end which is the inner peripheral end, A first ground pattern formed along the periphery of the first surface, A second ground pattern is formed in the air core portion of the antenna pattern on the second surface and is connected to the first ground pattern, A first wiring section connecting the output terminal and the starting end, A capacitor is included, and a second wiring section connects the first wiring section and the first ground pattern or the second ground pattern, A third wiring section connecting the first ground pattern or the second ground pattern to the ground terminal, A return path passing through the first wiring section, the second wiring section, the first ground pattern or the second ground pattern, and the third wiring section, wherein the area of ​​the portion enclosed by the return path is 25% or less of the area of ​​the first surface. A contactless communication device.

2. A contactless communication device according to claim 1, The second wiring section connects the first wiring section to the ground pattern of the first ground pattern and the second ground pattern that is connected to the ground terminal via the third wiring section. Contactless communication device.

3. A contactless communication device according to claim 1, The second wiring section connects the first wiring section to the first ground pattern and the ground pattern of the second ground pattern that is not connected to the ground terminal via the third wiring section. Contactless communication device.

4. A contactless communication device according to claim 2, The second wiring section connects the first wiring section and the second ground pattern. The third wiring section connects the second ground pattern and the ground terminal. Contactless communication device.

5. A contactless communication device according to claim 2, The second wiring section connects the first wiring section and the first ground pattern. The third wiring section connects the first ground pattern and the ground terminal. Contactless communication device.

6. A contactless communication device according to claim 5, The first ground pattern has a fractured portion in which a part of it is broken, The second wiring section is connected to a location corresponding to the end of the first ground pattern formed by the break. Contactless communication device.

7. A contactless communication device according to claim 3, The second wiring section connects the first wiring section and the first ground pattern. The third wiring section connects the second ground pattern and the ground terminal. The contactless communication device further comprises a fourth wiring section that connects the first ground pattern and the third wiring section. Contactless communication device.

8. A contactless communication device according to claim 7, The first ground pattern has a first fractured portion in which a part of it is broken, a second fractured portion in which another part is broken, and an isolated region formed between the first fractured portion and the second fractured portion. Contactless communication device.

9. A contactless communication device according to claim 7, The second wiring section connects the first wiring section to the isolated region of the first ground pattern, The fourth wiring section connects the isolated region of the first ground pattern and the third wiring section. Contactless communication device.

10. A contactless communication device according to claim 1, The return path is such that the area enclosed by the path is 20% or less of the area of ​​the first surface. Contactless communication device.

11. A contactless communication device according to claim 10, The return path is such that the area enclosed by the path is 15% or less of the area of ​​the first surface. Contactless communication device.

12. A contactless communication device according to claim 11, The return path is such that the area enclosed by the path is 10% or less of the area of ​​the first surface. Contactless communication device.

13. A contactless communication device according to claim 12, The return path is defined such that the area enclosed by the path is 5% or less of the area of ​​the first surface. Contactless communication device.

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