Electronic device

Abstract

Provided is an electronic device comprising: a substrate (10); a first antenna (20) and a second antenna (30) that are formed on the substrate (10) and that each perform wireless communication; a ground pattern (11) formed by a single conductor layer of the substrate (10); and a slit (40) that is formed by cutting out the conductor layer and has a base point that is a point on the outer periphery of the ground pattern (11), in a plan view, the first antenna (20) is provided within a first antenna region (21) surrounded by the outer periphery of the substrate (10) and the conductor layer, and in a plan view, the second antenna (30) is provided within a second antenna region (31) surrounded by the outer periphery of the substrate (10) and the conductor layer. A base point of the slit (40) is located between the first antenna region (21) and the second antenna region (31) in a plan view, and the slit (40) has a portion facing an end portion of the first antenna region (21) on the side opposite the outer peripheral side of the substrate (10) in the plan view.

Description

Technical Field

[0001] This invention relates to electronic devices including antennas for wireless communication. Background Technology

[0002] Electronic devices, including those with antennas for performing wireless communication connections with other communication devices (such as wireless local area network (LAN) communication based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard or wireless communication based on the Bluetooth (registered trademark) standard), are already known. One type of such antenna has a patterned antenna formed of a conductor layer on the front surface of a printed circuit board or similar surface. Summary of the Invention

[0003] Technical issues

[0004] In the electronic devices described above, some include multiple antennas. When multiple antennas are formed on a single substrate, there is a risk that these antennas may interfere with each other due to radiated currents propagating through the conductor layers on the printed circuit board, thereby adversely affecting wireless communication.

[0005] The present invention was made in view of the above circumstances, and its object is to provide an electronic device that can suppress the propagation of radiated current by means of an antenna mounted on a substrate.

[0006] Solution to the problem

[0007] An electronic device according to the invention includes a substrate, a first antenna and a second antenna formed on the substrate and respectively configured to perform wireless communication, a ground pattern formed by a single conductor layer of the substrate, and a slit formed by cutting out the conductor layer, the slit having a base point, the base point being a point on the outer periphery of the ground pattern, wherein the first antenna is arranged in a plan view within a first antenna region surrounded by the outer periphery of the substrate and the conductor layer, the second antenna is arranged in a plan view within a second antenna region surrounded by the outer periphery of the substrate and the conductor layer, the base point of the slit is located between the first antenna region and the second antenna region in the plan view, and the slit has an end on a side opposite to one side of the outer periphery of the substrate of the first antenna region in the plan view. Attached Figure Description

[0008] Figure 1 This is a perspective view illustrating the appearance of a substrate of an electronic device incorporated in an embodiment of the present invention.

[0009] Figure 2 This is a partial top view illustrating the substrate of an electronic device incorporated in an embodiment of the present invention.

[0010] Figure 3A diagram depicting an example of the distribution of radiated current in an electronic device according to an embodiment of the present invention is shown.

[0011] Figure 4 This is a diagram illustrating an example of simulation results for antenna-to-antenna isolation in an electronic device according to an embodiment of the present invention.

[0012] Figure 5 This is a partial top view of the substrate of an electronic device incorporated in a variation of the present invention.

[0013] Figure 6 This is a partial top view of the substrate of an electronic device incorporated in other variations of the present invention.

[0014] Figure 7 This is a top view of a portion of the substrate of an electronic device incorporated in a variation of the present invention, which has a meandering slit.

[0015] Figure 8 This is a partial top view of the surface side of a substrate in a variation of the present invention in which antennas and slits are formed in different conductor layers.

[0016] Figure 9 This is a partial plan view of the back side of the substrate in a variation of the present invention, wherein the antenna and the slit are formed in different conductor layers.

[0017] Figure 10 This is a top view of a substrate of an electronic device incorporated in a variation of the present invention, which has a plurality of slits formed. Detailed Implementation

[0018] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0019] An electronic device 1 according to an embodiment of the present invention is, for example, a personal computer, a home video game console, a handheld game console, or a smartphone, and includes a substrate 10, a first antenna 20, and a second antenna 30. Figure 1 This is a perspective view illustrating an example of the appearance of the substrate 10 built into the electronic device 1. Further, Figure 2 This is a partial plan view of a portion of the substrate 10, shown in an enlarged manner. Note that all figures below are schematic diagrams illustrating the features of the electronic device 1 according to this embodiment, and the scale, etc., differ from the actual figures. Furthermore, parts not directly related to the description herein have been appropriately omitted.

[0020] The substrate 10 is an electronic circuit board on which various circuit elements for implementing the functions of the electronic device 1 are mounted. In this embodiment, the substrate 10 has, as shown in the example below, Figure 1The illustrated flat plate shape is rectangular in plan view. In the following description, for ease of description, the horizontal direction of substrate 10 is defined as the X-axis, and the vertical direction as the Y-axis, and it is assumed that substrate 10 is positioned in a direction parallel to the XY plane. Furthermore, the direction orthogonal to substrate 10 is defined as the Z-axis, the direction toward the front surface of substrate 10 is defined as the positive Z-axis direction, and the direction toward the rear surface is defined as the negative Z-axis direction. On the front surface of substrate 10, a ground pattern 11 is formed on approximately the entire surface by a conductor layer. Note that in... Figure 2 In the image, the portion of the front surface of the substrate 10 in which the conductor layer is formed is indicated by a shaded line.

[0021] The first antenna 20 and the second antenna 30 are both circuit elements used to enable electronic device 1 to communicate wirelessly with other electronic devices. The first antenna 20 and the second antenna 30 can be antennas used to perform wireless communication according to different communication standards, or they can be antennas used to perform wireless communication according to the same communication standard.

[0022] In this embodiment, similar to the grounding pattern 11, it is assumed that the first antenna 20 and the second antenna 30 are patterned antennas formed by a conductor layer on the front surface of the substrate 10. Furthermore, both the first antenna 20 and the second antenna 30 are disposed along one side of the substrate 10. Hereinafter, among the four sides forming the outer periphery of the substrate 10, the side where the first antenna 20 and the second antenna 30 are disposed will be referred to as side N. Here, side N is the side along the X-axis direction.

[0023] More specifically, the first antenna 20 is formed by a conductive layer within the first antenna region 21. The first antenna region 21 is the area on the front surface of the substrate 10 that includes the first antenna 20, and is the area where no conductive layer is formed except for the first antenna 20. The first antenna region 21 is a generally rectangular area surrounded by the ground pattern 11 and the outer periphery of the substrate 10 in a plan view. The lower side of the first antenna region 21 faces side N of the substrate 10, and the other three sides are adjacent to the ground pattern 11.

[0024] The feed point P1 of the first antenna 20 is located on the upper side of the first antenna region 21 (i.e., on the outer periphery of the first antenna region 21, on the side opposite to the outer periphery of the substrate 10 where an end is formed). Furthermore, one end of the first antenna 20 is connected to the grounding pattern 11 at the right side of the first antenna region 21 (i.e., on the outer periphery of the first antenna region 21, on the side closer to the second antenna 30 where an end is formed). Figure 2 Point P2 in the middle).

[0025] The second antenna 30 is formed by a conductive layer within the second antenna region 31. Similar to the first antenna region 21, the second antenna region 31 is the area on the front surface of the substrate 10 that includes the second antenna 30, and is the area where no conductive layer is formed except for the second antenna 30. The second antenna region 31 is a generally rectangular area surrounded by the ground pattern 11 and the outer periphery of the substrate 10 in a plan view. The lower side of the second antenna region 31 faces side N of the substrate 10, and the other three sides are adjacent to the ground pattern 11.

[0026] Furthermore, the second antenna 30 has a shape that is approximately symmetrical to the shape of the first antenna 20, and its center line is a line parallel to the Y-axis. Specifically, the feed point P3 of the second antenna 30 is arranged on the upper side of the second antenna region 31 (i.e., on the outer periphery of the second antenna region 31, on the side opposite to the outer periphery of the substrate 10 where the end is formed). Additionally, one end of the second antenna 30 is connected to the ground pattern 11 at the left side of the second antenna region 31 (i.e., on the outer periphery of the second antenna region 31, on the side closer to the first antenna 20 where the end is formed). Figure 2 Point P4 in the middle.

[0027] Assume that the first antenna 20 and the second antenna 30 each perform wireless communication at at least a portion of the same frequency. For example, assume that the first antenna 20 performs wireless LAN communication based on the IEEE 802.11 standard, and the second antenna 30 performs wireless communication based on the Bluetooth standard. In this case, both use frequencies around 2.4 GHz for wireless communication. Hereinafter, λ represents the wavelength corresponding to the frequency shared by the first antenna 20 and the second antenna 30.

[0028] The first antenna 20 and the second antenna 30 each generate radiated currents that propagate along the grounding pattern 11 during wireless communication. Such radiated currents pose a risk of becoming noise relative to each other and interfering with each other's wireless communication. Therefore, in this embodiment, the grounding pattern 11 between the first antenna 20 and the second antenna 30 is formed by cutting out a conductor layer in an elongated shape to create a slit 40. The radiated current primarily propagates along the outer periphery of the grounding pattern 11, but with the arrangement of the slit 40, the current propagates in a meandering manner along the outer periphery of the slit 40. At this time, the current flows in opposite directions on the corresponding sides of the slit 40, thus preventing the radiated current from propagating to the opposite side of the slit 40.

[0029] A base point P5 of a slit 40 is located on the outer periphery of the grounding pattern 11 between the first antenna region 21 and the second antenna region 31. The slit 40 has a straight base 41 extending from the base point P5 in the positive Y-axis direction (i.e., the rear side of the substrate 10). At the distal end of the base 41 (the end opposite to the base point P5), the slit 40 bends at approximately a right angle and extends further in the negative X-axis direction (i.e., towards the side closer to the first antenna 20). The portion extending further from the distal end of the base 41 of the slit 40 in a bent manner is referred to hereinafter as the bent portion 42. And, hereinafter, the distal end of the bent portion 42 (i.e., the innermost part of the slit 40) is referred to as the distal end P6. The slit 40 has a generally constant width, and its width is much smaller than the total length of the slit 40.

[0030] The slit 40 can suppress the propagation of radiated current at a wavelength corresponding to the electrical length Le of the slit 40. Therefore, in this embodiment, the total length L of the slit 40 (i.e., the sum of the length of the base 41 and the length of the bend 42) is set to a length corresponding to the wavelength λ of the wireless communication used by the first antenna 20 and the second antenna 30. In this way, the slit 40 can suppress the propagation of radiated current that may adversely affect wireless communication and occur between the first antenna 20 and the second antenna 30.

[0031] Specifically, the electrical length Le of the slit 40 is preferably at least (1 / 8)λ but less than (3 / 8)λ, and more preferably a length approximately matching (1 / 4)λ, to correspond to the wavelength λ of wireless communication. In this embodiment, since the slit 40 is formed by cutting out a portion of a conductor layer disposed on the substrate of the substrate 10, the electrical length Le is calculated by the following formula, where ε represents the relative permittivity of the dielectric of the substrate forming the substrate 10.

[0032]

[0033] That is, by forming a slit 40 on a dielectric with a relative permittivity ε, it is possible to shorten the physical length L of the slit 40 required to suppress radiation current of the same wavelength.

[0034] Furthermore, in this embodiment, the distal end of the slit 40 extends to the left side (first antenna 20 side) of the right side of the first antenna region 21 (i.e., the side closer to the slit 40). This design creates a portion where, in a plan view, the lower side of the distal end of the slit 40 (i.e., the side closer to the first antenna region 21) and the upper side of the first antenna region 21 (i.e., the side closer to the distal end of the slit 40, and the side where the end is formed on the side opposite to side N of the substrate 10) both extend substantially parallel to each other along the X-axis direction and are opposite each other.

[0035] like Figure 2As shown by the dashed arrow, when the first antenna 20 performs wireless communication, the radiated current is affected and flows from the feed point P1 toward the slit 40 (i.e., to the right) along the outer periphery of the grounding pattern 11 adjacent to the first antenna region 21. Furthermore, the radiated current propagating along the outer periphery of the grounding pattern 11 flows around the slit 40 in a meandering manner. That is, the radiated current flows to the left along the lower side of the bend 42 of the slit 40 toward the distal end P6 of the slit 40. With this design, currents flowing in opposite directions flow in the portion of the grounding pattern 11 sandwiched between the upper side of the first antenna region 21 and the lower side of the bend 42 of the slit 40. These opposing currents have a mutually canceling effect, thereby providing the effect of suppressing the propagation of the radiated current. Thus, when the slit 40 is formed such that the distal end of the slit 40 is opposite to the upper side of the first antenna region 21 (the side opposite to the outer periphery of the substrate 10), the propagation of the radiated current can be suppressed more effectively compared to the case where there is no opposing portion.

[0036] Note that to establish a relative portion between the distal end of slit 40 and the upper side of the first antenna region 21, the position of the distal end P6 along side N (i.e., the X-axis direction) must be located to the left of the right side of the first antenna region 21 (on the side of the first antenna 20). Furthermore, even if the bend 42 of slit 40 extends to the left of the feed point P1 of the first antenna 20 (opposite to the base point P5 side of slit 40), the direction of the current flowing in the relative portion is not opposite in the region to the left of the feed point P1, thus failing to suppress the propagation of the radiated current. Therefore, the position of the distal end P6 of slit 40 along side N is ideally located within the range between the end of slit 40 on the first antenna region 21 and the feed point P1. Figure 2 Within the range shown by R in the middle.

[0037] Furthermore, when the distance between the distal end of the slit 40 and the first antenna region 21 is large, the effect of suppressing the propagation of radiated current cannot be sufficiently obtained. The inventors of this application have discovered that when the distance d along the Y-axis between the lower side of the distal end of the slit 40 and the upper side of the first antenna region 21 is set to be equal to or less than 1 / 16 of the wavelength λ used for wireless communication, the effect of suppressing the propagation of radiated current becomes particularly significant through verification including simulation. Note that when the distance between the relative portions of the distal end of the slit 40 and the first antenna region 21 is not constant, the slit 40 is ideally configured such that the distance d at least at the portion of the slit 40 closest to the first antenna region 21 becomes equal to or less than 1 / 16 of the wavelength λ.

[0038] Figure 3A graph depicts simulation results comparing the distribution of radiated current generated in the grounding pattern 11 of the substrate 10 when wireless communication is performed by the first antenna 20, for various substrate types that differ from each other. Specifically, Figure 3 (a) shows the distribution without slit 40. Figure 3 (b) shows the distribution of cases where a linear slit is formed instead of slit 40, and Figure 3 (c) illustrates the distribution of cases forming the L-shaped slit 40 in this embodiment. Note that in Figure 3 (b) and Figure 3 In (c), the slit lengths are essentially matched, and their electrical lengths are approximately 1 / 4 of the length corresponding to the wavelength λ. Note that in (a) to... Figure 3 In (c), the areas with higher shaded intensity indicate locations where large radiative currents have been generated.

[0039] like Figure 3 (a) to Figure 3 As shown in (c), without any slits, the radiated current generated by the first antenna 20 propagates to the second antenna 30. Conversely, with the linear slits, a relatively large radiated current distribution occurs along the slits, and although the radiated current propagating to the second antenna 30 is reduced, the radiated current still propagates to some extent around the second antenna 30 and the second antenna region 31. Meanwhile, in this embodiment, although a strong radiated current distribution occurs near the bend 42, compared to the case with the linear slits, the radiated current propagating beyond the slit 40 to the side of the second antenna 30 is further reduced and has almost no effect.

[0040] also, Figure 4 This is a graph showing the simulation results for the antenna-to-antenna isolation performance between the first antenna 20 and the second antenna 30. The horizontal axis of the graph represents frequency, and the vertical axis represents the isolation value, where a smaller value indicates better antenna-to-antenna isolation (i.e., a smaller degree of mutual interference between the first antenna 20 and the second antenna 30).

[0041] In this chart, as Figure 3 of (a), Figure 3 (b) Figure 3 As illustrated in (c), cases without a slit, cases with a linear slit, and cases with... Figure 1 , Figure 2The simulation results for the three patterns of the illustrated L-shaped slit 40 are shown. Specifically, in the graph, the dashed line represents the simulation result without the slit, the single-dotted line represents the simulation result with the linear slit, and the solid line represents the simulation result with the slit 40 of this embodiment. It has been confirmed, as shown in the graph, that according to this embodiment, not only compared to the case without any slit, but also compared to the case with the linear slit, the isolation is significantly improved near the frequency corresponding to the wavelength λ of 2.4 GHz.

[0042] As described above, using the electronic device 1 according to this embodiment, a slit 40 having a portion opposite to the upper side of the first antenna region 21 is formed in the conductor layer, thereby suppressing the propagation of radiated current between the first antenna 20 and the second antenna 30, and reducing mutual interference between the first antenna 20 and the second antenna 30. Specifically, in this embodiment, since the slit 40 is provided to improve isolation, the distance between the first antenna 20 and the second antenna 30 can be reduced to equal to or less than (1 / 4)λ. This relaxes the constraints on circuit layout. Furthermore, in this embodiment, the slit 40 has a bent shape, with its distal end positioned relatively close to the first antenna region 21. Therefore, compared to, for example, arranging a linear slit, the space required to arrange the slit 40 is smaller.

[0043] Note that it has been assumed that the wavelength λ in the above description is the wavelength corresponding to the wireless communication frequency used by both the first antenna 20 and the second antenna 30. In this way, the slit 40 can suppress both the radiated current propagating from the first antenna 20 to the second antenna 30 side and the radiated current propagating from the second antenna 30 to the first antenna 20 side, thereby effectively improving the isolation between the first antenna 20 and the second antenna 30. However, embodiments of the present invention are not limited to this configuration. It is sufficient that the wavelength λ is the wavelength corresponding to the wireless communication frequency used by the first antenna 20; the wavelength λ may also not be the wavelength corresponding to the wireless communication frequency used by the second antenna 30. Even in this case, the slit 40 having an electrical length Le corresponding to the wavelength λ is disposed between the first antenna 20 and the second antenna 30 as described above, thereby suppressing the propagation of the radiated current corresponding to the wavelength λ generated from the first antenna 20 to the second antenna 30 side. Furthermore, the distance d between the lower side of the distal end of the slit 40 and the upper side of the first antenna region 21 is set to be (1 / 16)λ or less relative to the wavelength λ corresponding to the wireless communication frequency used by the first antenna 20, thereby effectively suppressing the propagation of the radiated current from the first antenna 20.

[0044] [Variation Example]

[0045] The embodiments of the present invention are not limited to the above description, and various modifications can be implemented.

[0046] For example, the first antenna 20 and the second antenna 30 can be arranged along different sides of the same substrate 10. Figure 5 An example of an electronic device based on this variant is shown. Figure 5 In the example, the first antenna 20 is as follows Figure 1 and Figure 2 The second antenna 30 is positioned along the negative Y-axis direction, while the third antenna 30 is positioned along the positive X-axis direction, which is different from the previously mentioned side. Even in this case, it is still similar to... Figure 1 Similarly, a slit 40 is formed on the outer periphery of the grounding pattern 11 on the side where the first antenna 20 is arranged, having a base point P5 and curving toward the rear side of the first antenna region 21 (the side opposite to the outer periphery of the substrate 10). In this way, current cancellation occurs in the portion of the upper side of the first antenna region 21 and the distal end of the slit 40 that are opposite to each other, thereby improving the isolation between the first antenna 20 and the second antenna 30.

[0047] Furthermore, when the first antenna 20 and the second antenna 30 are located on different sides, the base point P5 of the slit 40 may not be located along the side where the first antenna 20 is located, but rather along the side where the second antenna 30 is located. In this case, the slit 40 does not necessarily need to have a bent shape, and it is also possible to provide a portion in which the distal end of the slit 40 is opposite to the side of the first antenna region 21 that is opposite to the outer periphery of the substrate 10.

[0048] Figure 6 An example of an electronic device according to this variant is shown. In this example, the slit 40 has a base point P5 on the outer periphery of the side of the ground pattern 11 where the second antenna 30 is arranged, and has a linear shape extending toward the side where the first antenna 20 is arranged. Also in this example, the position of the distal end P6 of the slit 40 in the X-axis direction (i.e., along the side of the substrate 10 where the first antenna region 21 is arranged) is located between the feed point P1 of the first antenna 20 and the right side of the first antenna region 21 (i.e., the side closer to the base point P5 of the slit 40). Thus, the lower side of the distal end of the slit 40 is opposite to the upper side of the first antenna region 21. Radiation currents oriented in opposite directions flow in the conductor layer sandwiched between these two opposite sides, thereby enabling an improvement in the isolation between the first antenna 20 and the second antenna 30, such as... Figure 1 Examples like those.

[0049] Furthermore, the slit 40 is not limited to the above and can have various shapes, as long as the slit 40 has a portion on its distal side opposite to the upper side of the first antenna region 21. As an example, Figure 7An example is shown where the slit 40 has a meandering shape with bends at multiple locations. Also in this example, the distal end of the slit 40 faces the upper side of the first antenna region 21, and the distal end P6 is located between the right side of the first antenna region 21 and the feed point P1 of the first antenna 20. Thus, it is possible to... Figure 1 Examples of improving the isolation between the first antenna 20 and the second antenna 30, etc.

[0050] Furthermore, in the above description, it has been assumed that the slit 40 is formed on the same conductor layer as the first antenna 20 and the second antenna 30. That is, the first antenna 20, the second antenna 30, and the ground pattern 11 are formed on the front surface of the substrate 10 by a single conductor layer, and the slit 40 is formed by cutting out a portion of the ground pattern 11. However, embodiments of the present invention are not limited to this configuration, and the slit 40 may be formed in a conductor layer different from the conductor layer used for either or both of the first antenna 20 and the second antenna 30.

[0051] Now, using Figure 8 and Figure 9 An example of a substrate 10 in an electronic device according to such a variation is described. Figure 8 This is a partial top view of the surface side of the substrate 10. Figure 9 This is a partial top view of the back side of the substrate 10 at the corresponding position.

[0052] In this modified example, as in Figure 1 In this embodiment, the grounding pattern 11, the first antenna 20, and the second antenna 30 are formed by a conductor layer formed on the front surface side of the substrate 10. Furthermore, in the grounding pattern 11, a slit 40 is formed at a base point P5 between the first antenna 20 and the second antenna 30. However, compared to... Figure 1 Unlike in this embodiment, due to circuit layout constraints, the length to the far end of slit 40 is longer than... Figure 1 As illustrated, the slit 40 is short, therefore, there is no longer a portion at the far end of the slit 40 that is opposite to the upper side of the first antenna region 21.

[0053] Simultaneously, a grounding pattern 12 is formed on the back surface side of the substrate 10 through a conductor layer. In this grounding pattern 12, a rectangular region overlapping the first antenna region 21 on the front surface side in the plan view is cut out, thereby forming a first back surface region 22. Furthermore, a rectangular region overlapping the second antenna region 31 on the front surface side in the plan view is also cut out, thereby forming a second back surface region 32. That is, similar to the grounding pattern 11 on the front surface side, the grounding pattern 12 on the back surface side in the plan view is also formed in a manner that avoids the formation positions of the first antenna 20 and the second antenna 30. Note that in Figure 9 In the diagram, the positions of the first antenna 20 and the second antenna 30 are indicated by dashed lines.

[0054] Furthermore, in the grounding pattern 12, a slit 50 is formed at a position that partially overlaps with the slit 40 in the plan view. The slit 50 in this modified example has a shape and size similar to the slit 40 in the embodiment of FIG1, and has an overall electrical length Le corresponding to the wavelength λ.

[0055] Specifically, the slit 50 includes a base 51, which extends linearly along the positive Y-axis (i.e., toward the center of the substrate 10) with a base point P7 that coincides with the base point P5 of the slit 40 in the plan view. The base 51 matches the base 41 of the front surface side slit 40 in position, shape, and size.

[0056] The slit 50 includes a bend 52 that bends at the end of the base 51 on the side opposite to the base point P7 and extends further toward the negative X-axis direction. The length of the bend 52 is greater than that of the bend 42 of the front surface side slit 40, and as its Figure 1 As shown, the distal end of the bend 52 has a portion opposite to the first back surface region 22. That is, in the plan view, the position of the distal end P8 of the bend 52 along the X-axis is within the range R between the right side of the first antenna region 21 (the side forming the end of the second antenna 30) and the feed point P1 of the first antenna 20, and the distal end of the bend 52 is opposite to the upper side of the first antenna region 21 in the plan view. Furthermore, in the plan view, the distance d between the lower side of the slit 50 and the upper side of the first antenna region 21 is (1 / 16)λ or less. Note that... Figure 8 The dashed line in the figure indicates the position of the slit 50 on the back surface side.

[0057] Furthermore, the grounding pattern 11 on the front surface side and the grounding pattern 12 on the back surface side are electrically connected to form the ground of the circuit. In particular, in this modified example, a plurality of through holes 13 penetrating the substrate 10 are arranged around the slit 50 at constant intervals along the outer periphery of the slit 50, and the grounding pattern 11 is electrically connected to the grounding pattern 12 at the locations of these through holes 13. As a result, the radiated current generated by the first antenna 20 also propagates to the grounding pattern 12 and flows along the outer periphery of the slit 50. Therefore, the slit 50 formed on the grounding pattern 12 on the back surface side in this modified example can suppress the propagation of the radiated current between the first antenna 20 and the second antenna 30, just like the slit 40 on the front surface side in the embodiments of FIG1, thereby improving the isolation between the first antenna 20 and the second antenna 30.

[0058] It should be noted that in this modified example, it is assumed that a slit 50 is formed on the grounding pattern 12 on the back surface side, having a portion opposite to the upper side of the first antenna region 21 in the plan view. However, the electronic device involved in the embodiments of the present invention is not limited to this. If the substrate 10 is a multilayer substrate, a slit satisfying the above requirements can also be formed in the inner conductor layer of the substrate 10. Furthermore, slits can be formed in multiple layers such as the surface-side conductor layer, the back surface-side conductor layer, or the inner conductor layer, respectively, in an overlapping manner when viewed from above. In addition, slits can be formed in each of multiple layers such as the front surface-side conductor layer, the back surface-side conductor layer, or the inner conductor layer, respectively, in an overlapping manner in the plan view.

[0059] Furthermore, in the above description, it is assumed that only a single slit 40 is arranged with a base point at a certain position between the first antenna region 21 and the second antenna region 31. However, the electronic device involved in the embodiments of the present invention is not limited to this, and multiple slits may also be formed between the first antenna region 21 and the second antenna region 31.

[0060] Figure 10 is a partial top view of the substrate 10 incorporating the electronic device based on this modified example. It should be noted that, in the following description, the wavelength corresponding to the wireless communication frequency used by the first antenna 20 is denoted as λ1, and the wavelength corresponding to the wireless communication frequency used by the second antenna 30 is denoted as λ2. Here, wavelength λ1 does not necessarily need to correspond to the wireless communication frequency used by the second antenna 30, and wavelength λ2 does not necessarily need to correspond to the wireless communication frequency used by the first antenna 20. However, when both wavelengths λ1 and λ2 correspond to the wireless communication frequencies used by both the first antenna 20 and the second antenna 30, it is expected that the isolation between the first antenna 20 and the second antenna 30 can be further improved. Hereinafter, as a specific example, two frequencies, approximately 2.4 GHz and 5 GHz, are used as the frequencies used by the first antenna 20 and the second antenna 30 for wireless communication, and λ1 and λ2 denote the wavelengths corresponding to each frequency.

[0061] In the example of Figure 10, the slit 40 is similar to the slit in the embodiments of Figure 1, also having a portion opposite to the first antenna region 21. Furthermore, in this modified example, to adapt to the wavelength λ1, the electrical length Le of the slit 40 is preferably at least (1 / 8)λ1 and less than (3 / 8)λ1, more preferably a length approximately matching (1 / 4)λ1. Figure 10In the example, the overall electrical length of slit 40 is equivalent to 1 / 4 of the wavelength λ1. Through this design, slit 40 can suppress the propagation of radiated current with wavelength λ1 between the first antenna 20 and the second antenna 30. Furthermore, the distance d1 between the distal end of slit 40 and the upper side of the first antenna region 21 is equal to or less than 1 / 16 of λ1.

[0062] In addition to slit 40, a slit 60 is also formed. Similar to slit 40, slit 60 is L-shaped, bending towards the second antenna 30, with a base point P9 on the outer periphery of the grounding pattern 11 on the side where the first antenna 20 and the second antenna 30 are located. To adapt to wavelength λ2, the electrical length Le of slit 60 is preferably at least (1 / 8)λ2 and less than (3 / 8)λ2, more preferably a length approximately matching (1 / 4)λ2. In the example of Figure 10, the overall electrical length of slit 60 is equivalent to 1 / 4 of wavelength λ2. Through this design, slit 60 can suppress the propagation of radiated current with wavelength λ2 between the first antenna 20 and the second antenna 30.

[0063] Furthermore, the distal end of the slit 60 has a portion opposite to the upper side of the second antenna region 31 (i.e., the side formed by the end of the outer periphery of the second antenna region 31 opposite to the outer periphery of the substrate 10). Moreover, the position of the distal end P10 of the slit 60 along side N (i.e., the X-axis direction) is preferably located within the range between the left side of the second antenna region 31 (the side formed by the end near the first antenna 20) and the feed point P3 of the second antenna 30 (the range indicated by R2 in FIG10). Furthermore, the distance d2 between the distal end of the slit 60 and the upper side of the second antenna region 31 (i.e., the side formed by the end of the outer periphery of the second antenna region 31 opposite to the outer periphery of the substrate 10) can be set to be equal to or less than 1 / 16 of λ2.

[0064] By using multiple slits arranged in this manner between the first antenna 20 and the second antenna 30, the propagation of radiated currents at multiple wavelengths corresponding to each electrical length can be suppressed.

[0065] [List of reference numerals]

[0066] 1: Electronic devices

[0067] 10: Substrate

[0068] 11, 12: Grounding patterns

[0069] 20: First Antenna

[0070] 21: First antenna region

[0071] 30: The Second Line

[0072] 31: Second Line Area

[0073] 40, 50, 60: Slit

Claims

1. An electronic device, comprising: substrate; A first antenna and a second antenna are formed on the substrate and each is configured to perform wireless communication. A grounding pattern, the grounding pattern being formed from a single conductor layer of the substrate; and A slit, formed by cutting through the conductor layer, has a base point, which is a point on the outer periphery of the grounding pattern, wherein... In the plan view, the first antenna is positioned within the first antenna region surrounded by the outer periphery of the substrate and the conductor layer. In the plan view, the second antenna is positioned within the second antenna region surrounded by the outer periphery of the substrate and the conductor layer. In the plan view, the base point of the slit is located between the first antenna region and the second antenna region. In the plan view, the slit has a portion opposite to the end of the first antenna region on the side opposite to the outer periphery of the substrate.

2. The electronic device according to claim 1, wherein, The opposing portion is the portion of the slit's distal end that faces the end of the first antenna region on the side opposite to the outer periphery of the substrate. The distal end of the slit is located in the direction along the outer periphery of the substrate between the end of the second antenna side of the first antenna region and the feed point of the first antenna.

3. The electronic device according to claim 1 or 2, wherein, In the relative portion, in the plan view, the distance between the slit and the first antenna region is equal to or less than 1 / 16 of the wavelength corresponding to the wireless communication frequency used by the first antenna.

4. The electronic device according to claim 3, wherein, The wavelength is the wavelength corresponding to the wireless communication frequency used by both the first antenna and the second antenna.

5. The electronic device according to claim 1, wherein, The electrical length of the slit is more than 1 / 8 but less than 3 / 8 of the wavelength corresponding to the wireless communication frequency used by the first antenna.

6. The electronic device according to claim 5, wherein, The wavelength is the wavelength corresponding to the wireless communication frequency used by both the first antenna and the second antenna.

7. The electronic device according to claim 1, wherein, The slit includes: The base extends from a base point on the outer periphery of the grounding pattern to the center side of the substrate, and A bend, the bend extending from the base to the side facing the first antenna, and The distal end of the bent portion is opposite to the end of the first antenna region on the side opposite to the outer periphery of the substrate.

8. The electronic device according to claim 1, wherein, The grounding pattern having the slit is formed by a conductor layer that is different from the conductor layer formed by at least one of the first antenna and the second antenna.

9. The electronic device according to claim 1, further comprising: The second slit, formed by cutting through the conductor layer, has a base point, which is a point on the outer periphery of the grounding pattern, wherein... In the plan view, the base point of the second slit is located between the first antenna region and the second antenna region, and In the plan view, the second slit has a portion opposite to the end of the second antenna region on the side opposite to the outer periphery of the substrate.

10. The electronic device according to claim 9, wherein, The portion of the second slit opposite to the end of the second antenna region is the portion of the distal end of the second slit opposite to the end of the second antenna region on the side opposite to the outer periphery of the substrate. The distal end of the second slit is located in the direction along the outer periphery of the substrate between the end of the second antenna region on the first antenna side and the feed point of the second antenna.

11. The electronic device according to claim 9 or 10, wherein, In the portion of the second slit opposite the end of the second antenna region, in the plan view, the distance between the slit and the second antenna region is equal to or less than 1 / 16 of the wavelength corresponding to the wireless communication frequency used by the second antenna.

12. The electronic device according to claim 9, wherein, The electrical length of the second slit is more than 1 / 8 but less than 3 / 8 of the wavelength corresponding to the wireless communication frequency used by the second antenna.

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