Antenna Device

Abstract

To provide an antenna device capable of expanding a bandwidth in which desired antenna characteristics can be obtained.SOLUTION: An antenna device 1 includes a substrate 10, and an antenna element ANT and a first ground conductor G1 which are provided on one surface 11 side of the substrate 10. The antenna element ANT includes a radiation conductor 20, power feed lines 31 and 32 for feeding power to the radiation conductor 20, and power feed coupling portions 41 and 42 connected between the radiation conductor 20 and the power feed lines 31 and 32. The first ground conductor G1 is spaced apart from the radiation conductor 20 by only a first distance F so as to surround at least a part of the peripheral edge of the radiation conductor 20. The power feed coupling portions 41 and 42 are wider than the power feed lines 31 and 32, and protrude from the radiation conductor 20. As a result, the antenna characteristics can be adjusted by the power feeding coupling portions 41 and 42.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an antenna device. [Background technology]

[0002] Patent Document 1 discloses an antenna device having a structure in which a radiating conductor and a ground conductor surrounding the periphery of the radiating conductor are provided on the surface of a substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-306495 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the antenna device described in Patent Document 1 has a problem in that it is difficult to adjust the antenna characteristics and it is not easy to achieve a broadband because the radiation conductor and the feed line are directly connected.

[0005] Therefore, an object of the present disclosure is to provide an antenna device capable of expanding the bandwidth over which desired antenna characteristics can be obtained. [Means for solving the problem]

[0006] An antenna device according to one embodiment of the present disclosure comprises a substrate, an antenna element and a first ground conductor provided on one surface side of the substrate, the antenna element having a radiating conductor, a feed line that feeds power to the radiating conductor, and a feed coupling portion connected between the radiating conductor and the feed line, the first ground conductor being arranged at a first distance so as to surround at least a portion of the periphery of the radiating conductor, the feed coupling portion being wider than the width of the feed line and protruding from the radiating conductor. Effect of the Invention

[0007] The present disclosure allows for an increase in the bandwidth over which the feed coupling provides desired antenna characteristics. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic plan view for explaining the structure of an antenna device 1 according to the first embodiment. [Diagram 2] FIG. 2 is a schematic partial cross-sectional view of the antenna device 1. [Diagram 3] FIG. 3 is a schematic partial cross-sectional view showing an example in which a second ground conductor G2 is formed on the other surface 12 of the base material 10. As shown in FIG. [Figure 4] FIG. 4 is a schematic partial cross-sectional view showing an example in which the antenna device 1 is placed on the surface of a display 13. As shown in FIG. [Diagram 5] FIG. 5 is a schematic plan view showing an enlarged view of the periphery of the power supply coupling portion 41. As shown in FIG. [Figure 6] FIG. 6 is a schematic plan view showing an enlarged view of the periphery of the power supply lines 31 and 32. As shown in FIG. [Figure 7] FIG. 7 is a schematic plan view for explaining the structure of the antenna device 2 according to the second embodiment. [Figure 8] FIG. 8 is a schematic plan view for explaining the structure of an antenna device 3 according to the third embodiment. [Figure 9] FIG. 9 is a schematic plan view for explaining the structure of an antenna device 4 according to the fourth embodiment. [Figure 10] FIG. 10 is a schematic plan view for explaining the structure of an antenna device 5 according to the fifth embodiment. [Figure 11] FIG. 11 is a schematic plan view for explaining the structure of an antenna device 6 according to the sixth embodiment. [Figure 12] FIG. 12 is a schematic plan view for explaining the structure of an antenna device 7 according to the seventh embodiment. [Figure 13] FIG. 13 is a graph showing the results of Example 1. [Figure 14]14(a) to 14(d) are schematic plan views for explaining the structures of samples S2a to S2d of Example 2, respectively. [Figure 15] FIG. 15 is a graph showing the results of Example 2. [Figure 16] FIG. 16 is a graph showing the results of Example 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0010] Fig. 1 is a schematic plan view for explaining the structure of an antenna device 1 according to a first embodiment, and Fig. 2 is a schematic partial cross-sectional view of the antenna device 1.

[0011] As shown in FIG. 1 and FIG. 2, the antenna device 1 according to the first embodiment includes a substrate 10, and an antenna element ANT and a first ground conductor G1 formed on one surface 11 of the substrate 10. The substrate 10 is made of a transparent insulating material, and may be, for example, a PET (polyethylene terephthalate) resin, a COP (cycloolefin polymer) resin, or glass. The other surface 12 of the substrate 10 may not have a conductor formed thereon as shown in FIG. 2, or may have a second ground conductor G2 formed at a position facing the radiation conductor 20 across the substrate 10 as shown in FIG. 3. When a conductor is not formed on the other surface 12 of the substrate 10, the display 13 functions as a ground conductor when the display 13 is placed on a surface of a device (e.g., a smartphone) in which the antenna device 1 is mounted, as shown in FIG. 4. In this case, the display 13 becomes the second ground conductor G2 facing the radiation conductor 20 across the substrate 10. In this way, the antenna device 1 according to the present embodiment configures a patch antenna with the second ground conductor G2 as a reference conductor.

[0012] In this embodiment, the antenna element ANT and the first ground conductor G1 are configured with a mesh-like conductor pattern. When the second ground conductor G2 is provided, the second ground conductor G2 is also configured with a mesh-like conductor pattern. This allows the antenna device 1 to be optically transparent, and the members located on the back side of the antenna device 1 can be seen from the front side of the antenna device 1. For example, as shown in FIG. 4, if the antenna device 1 according to this embodiment is placed on the surface of a display 13, the display content of the display 13 can be seen without being blocked by the antenna device 1.

[0013] The antenna element ANT includes a radiation conductor 20, power supply lines 31 and 32 that supply power to the radiation conductor, and power supply coupling parts 41 and 42 that are connected between the radiation conductor 20 and the power supply lines 31 and 32, respectively. The radiation conductor 20 is substantially square-shaped with a side length of A, and has four sides 21 to 24 that form a periphery. The sides 21 and 23 extend in the y direction, and the sides 22 and 24 extend in the x direction. The sides 21 and 22 face sides 51 and 52 that form a periphery of the first ground conductor G1. The sides 51 and 52 of the first ground conductor G1 extend in the y direction and the x direction, respectively. In this embodiment, the side 21 of the radiation conductor 20 faces the side 51 of the first ground conductor G1 over the entire width in the y direction, and the side 22 of the radiation conductor 20 faces the side 52 of the first ground conductor G1 over the entire width in the x direction. The first ground conductor G1 serves to expand the bandwidth by being arranged parallel to and close to the sides 21 and 22 of the radiating conductor 20. On the other hand, the first ground conductor G1 is not provided at a position facing the sides 23 and 24 of the radiating conductor 20. This is because even if the first ground conductor G1 is arranged parallel to and close to the sides 23 and 24 of the radiating conductor 20, there is no significant change in the bandwidth.

[0014] The feed lines 31 and 32 are sandwiched between the first ground conductor G1 from both sides, thereby forming a coplanar line. One end of the feed line 31 is connected to the port P1, and the other end of the feed line 31 is connected to the side 21 of the radiation conductor 20 via the feed coupling part 41. Similarly, one end of the feed line 32 is connected to the port P2, and the other end of the feed line 32 is connected to the side 22 of the radiation conductor 20 via the feed coupling part 42. The feed coupling parts 41 and 42 are wider than the width of the feed lines 31 and 32, and protrude from the sides 21 and 22 of the radiation conductor 20, respectively. The position of the feed coupling part 41 in the y direction is the center of the side 21, and the position of the feed coupling part 42 in the x direction is the center of the side 22.

[0015] Fig. 5 is a schematic plan view showing an enlarged view of the periphery of the power supply coupling portion 41. Fig. 6 is a schematic plan view showing an enlarged view of the periphery of the power supply lines 31 and 32.

[0016] As shown in FIG. 5, the power feed coupling portion 41 protrudes from the side 21 of the radiation conductor 20 in the x direction by a length B, and its width in the y direction is C. Although not shown, the power feed coupling portion 42 protrudes in the y direction by a length B, and its width in the x direction is also C. The tip 41a of the power feed coupling portion 41 extending in the y direction is a tip portion protruding from the radiation conductor 20 except for the connection position of the power feed coupling portion 41 with the feed line 31, and faces the side 51 of the first ground conductor G1 over the entire width in the y direction, thereby expanding the bandwidth. Although not shown, the tip of the power feed coupling portion 42 extending in the x direction is also a tip portion protruding from the radiation conductor 20 except for the connection position of the power feed coupling portion 42 with the feed line 32, and faces the side 52 of the first ground conductor G1 over the entire width in the x direction. The side 51 of the first ground conductor G1 and the side 21 of the radiation conductor 20 are spaced apart from each other by a first distance F in the x direction. The tip 41a of the power feed coupling portion 41 and the side 51 of the first ground conductor G1 are spaced apart in the x direction by a second distance FB, which is shorter than the first distance F. Although not shown, the side 52 of the first ground conductor G1 and the side 22 of the radiating conductor 20 are also spaced apart in the y direction by the first distance F. The tip 41a of the power feed coupling portion 42 and the side 52 of the first ground conductor G1 are spaced apart in the y direction by the second distance FB, which is shorter than the first distance F.

[0017] The antenna device 1 according to this embodiment can adjust the antenna characteristics by changing the first distance F and the second distance FB. In particular, the first distance F affects the bandwidth, and designing it narrower widens the bandwidth. Specifically, it is preferable to design the first distance F to be 0.15 times or less the wavelength of the electromagnetic wave used in wireless communication, and more preferably to design it to be 1 / 3 or less of the length A of one side of the radiating conductor 20. For example, when the frequency of the electromagnetic wave used in wireless communication is 26.875 GHz, it is preferable that the first distance F is 1 mm or less.

[0018] 6, the width of the power feed lines 31, 32 is D, and the space between the power feed lines 31, 32 and the first ground conductor G1 is E. The space E is an area where no mesh-shaped conductor pattern exists. An auxiliary pattern 60 added to the regular mesh is provided along the extension direction of the power feed lines 31, 32 at the boundary positions between the space E and the power feed lines 31, 32 and the first ground conductor G1. Note that the auxiliary pattern is provided on the entire periphery of the first ground conductor G1, not just at the boundary position with the space E. Similarly, the auxiliary pattern is provided on the entire periphery of the radiation conductor 20, the power feed lines 31, 32, and the power feed coupling parts 41, 42.

[0019] As described above, in the antenna device 1 according to the present embodiment, the antenna element ANT and the first ground conductor G1 are configured with a mesh-shaped conductor pattern, and therefore the optical transparency of the antenna device 1 can be ensured. In addition, in the antenna device 1 according to the present embodiment, the first ground conductor G1 is disposed close to the radiating conductor 20, and the power feed coupling parts 41, 42 are wider than the power feed lines 31, 32 and protrude from the radiating conductor 20, and therefore the bandwidth in which desired antenna characteristics can be obtained can be expanded. In addition, the antenna characteristics of the antenna device 1 can be adjusted by the sizes of the power feed coupling parts 41, 42 and the first distance F, which makes it easy to design.

[0020] FIG. 7 is a schematic plan view for explaining the structure of the antenna device 2 according to the second embodiment.

[0021] As shown in Fig. 7, the antenna device 2 according to the second embodiment has a configuration in which a plurality of antenna devices 1 according to the first embodiment described above (four in the example shown in Fig. 7) are arranged in one direction. The first ground conductor G1 is common to each of the radiation conductors 20, and is arranged to surround the sides 21 and 22. This makes it possible to configure a so-called phased array using a plurality of ports P1 to P8 that input and output signals, and makes it possible to arbitrarily change the beam direction.

[0022] FIG. 8 is a schematic plan view for explaining the structure of an antenna device 3 according to the third embodiment.

[0023] As shown in Fig. 8, the antenna device 3 according to the third embodiment differs from the antenna device 1 according to the first embodiment in that the first ground conductor G1 is provided so as to surround the entire circumference of the radiating conductor 20. In other words, the sides 23 and 24 of the radiating conductor 20 also face the first ground conductor G1 at a first distance F. By surrounding the entire circumference of the radiating conductor 20 with the first ground conductor G1 in this manner, the difference in light transmittance depending on the planar position is reduced, and therefore the aesthetic appearance is improved. In addition, the antenna element ANT becomes less noticeable, and the invisibility of the antenna ANT can be improved.

[0024] FIG. 9 is a schematic plan view for explaining the structure of an antenna device 4 according to the fourth embodiment.

[0025] 9, the antenna device 4 according to the fourth embodiment is different from the antenna device 1 according to the first embodiment in that the antenna element ANT and the first ground conductor G1 are not mesh-shaped but are a so-called solid pattern. When the antenna element ANT and the first ground conductor G1 are not mesh-shaped, the optical transparency is lost, but the antenna characteristics are further improved. As exemplified in this embodiment, it is not essential in the present disclosure that the antenna element ANT and the first ground conductor G1 are mesh-shaped.

[0026] FIG. 10 is a schematic plan view for explaining the structure of an antenna device 5 according to the fifth embodiment.

[0027] As shown in Fig. 10, the antenna device 5 according to the fifth embodiment differs from the antenna device 4 according to the fourth embodiment in that parasitic conductors 63, 64 are added along the sides 23, 24 of the radiating conductor 20. The parasitic conductors 63, 64 are part of the antenna element ANT, and are composed of a conductor pattern provided on one surface 11 side of the substrate 10. The parasitic conductors 63, 64 are insulated from the radiating conductor 20. By adding such parasitic conductors 63, 64, it is possible to further expand the bandwidth.

[0028] FIG. 11 is a schematic plan view for explaining the structure of an antenna device 6 according to the sixth embodiment.

[0029] 11, the antenna device 6 according to the sixth embodiment differs from the antenna device 4 according to the fourth embodiment in that the feed line 31 and the feed coupling portion 41 are omitted and the radiating conductor 20 is provided with cutouts 25 and 26. The cutout 25 is formed by cutting into a corner portion formed by the sides 21 and 22, and the cutout 26 is formed by cutting into a corner portion formed by the sides 23 and 24. By providing the cutouts 25 and 26 in two diagonally opposing corner portions of the radiating conductor 20 in this manner, it becomes possible to radiate a circularly polarized wave.

[0030] FIG. 12 is a schematic plan view for explaining the structure of an antenna device 7 according to the seventh embodiment.

[0031] 12, the antenna device 7 according to the seventh embodiment differs from the antenna device 4 according to the fourth embodiment in that the feed line 31 and the feed coupling portion 41 are omitted, and an aperture region 27 in which no conductor pattern exists is provided inside the radiation conductor 20. By providing such an aperture region 27, it becomes possible to radiate a circularly polarized wave according to the shape of the aperture region 27.

[0032] Although the above describes preferred embodiments of the present disclosure, the present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present disclosure, and it goes without saying that these modifications are also included within the scope of the present disclosure.

[0033] The technology according to the present disclosure includes the following configuration examples, but is not limited to these.

[0034] An antenna device according to one embodiment of the present disclosure comprises a substrate, an antenna element and a first ground conductor provided on one surface side of the substrate, the antenna element having a radiating conductor, a feed line that feeds power to the radiating conductor, and a feed coupling portion connected between the radiating conductor and the feed line, the first ground conductor being arranged at a first distance so as to surround at least a portion of the periphery of the radiating conductor, the feed coupling portion being wider than the width of the feed line and protruding from the radiating conductor.

[0035] According to this antenna device, the bandwidth in which the desired antenna characteristics can be obtained can be expanded by the feed coupling section.

[0036] The antenna device may further include a second ground conductor facing the radiation conductor with the base material interposed therebetween, whereby the antenna device functions as a patch antenna regardless of the configuration of the device in which it is mounted.

[0037] Furthermore, the tip of the feed coupling part may face the first ground conductor. This makes it possible to adjust the antenna characteristics by the second distance between the tip of the feed coupling part and the first ground conductor. In this case, the second distance between the tip of the feed coupling part and the first ground conductor may be shorter than the first distance. This makes it possible to simplify the shape of the first ground conductor.

[0038] The first distance may be equal to or less than 0.15 times the wavelength of the electromagnetic wave used in the wireless communication, which further increases the bandwidth.

[0039] The radiating conductor may have a substantially square shape in a plan view. In this case, the first distance may be ⅓ or less of the length of one side of the radiating conductor. This further increases the bandwidth. The feed coupling portion may protrude from the center of one of the four sides of the radiating conductor. This further increases the bandwidth. The radiating conductor may have notches formed by notching two diagonally opposing corners of one of the radiating conductors. This makes it possible to radiate circularly polarized waves.

[0040] Furthermore, the length of the periphery of the radiation conductor surrounded by the first ground conductor may be longer than ¼ of the length of the periphery of the radiation conductor, which further increases the bandwidth.

[0041] The antenna device may also include a plurality of feed lines and feed coupling parts, which allows a plurality of ports to be assigned to one radiation conductor, making it possible to support dual polarization.

[0042] The antenna element and the first ground conductor may be formed of a mesh-shaped conductor pattern, which makes it possible to provide an antenna device having optical transparency.

[0043] The antenna device may further include at least one parasitic conductor provided on one surface side of the base material and arranged around the radiating conductor so as to be insulated from the radiating conductor, thereby further expanding the bandwidth.

[0044] The antenna device may include a plurality of antenna elements, and the first ground conductor may be disposed so as to surround at least a portion of the periphery of each of the radiation conductors of the plurality of antenna elements, thereby forming a so-called phased array. EXAMPLES

[0045] <Example 1> A sample S1 having the same structure as the antenna device 1 shown in Fig. 1 was fabricated, and the antenna characteristics were measured. A COP resin having a thickness of 100 µm was used as the substrate 10, and a mesh-shaped Cu pattern having a line width of 1 µm and a pitch of 100 µm was used as the conductor pattern constituting the antenna element ANT and the first ground conductor G1. The length A of one side of the radiation conductor 20 was 2.95 mm, the protrusion amount B of the power feed coupling parts 41, 42 was 200 µm, the width C of the power feed coupling parts 41, 42 was 600 µm, the width D of the power feed lines 31, 32 was 200 µm, the space E between the power feed lines 31, 32 and the first ground conductor G1 was 30 µm, and the first distance F between the radiation conductor 20 and the first ground conductor G1 was 500 µm.

[0046] The measurement results are shown in Fig. 13. As shown in Fig. 13, sample S1 had a return loss of -10 dB or less in the 24.25 to 29.5 GHz band required by the 5G standard.

[0047] <Example 2> Samples S2a to S2d having the structures shown in Fig. 14(a) to (d) were fabricated and their antenna characteristics were measured. In the samples S2a to S2d, the width of the first ground conductor G1 in the antenna device 5 shown in Fig. 10 was set to 2 mm, 3 mm, 4 mm, and 5 mm, respectively. In the sample S2a, the first ground conductor G1 does not have a parallel side facing the sides 21 and 22 of the radiating conductor 20. In the sample S2b, the portions of the sides 21 and 22 of the radiating conductor 20 facing the sides 51 and 52 of the first ground conductor G1 are approximately 1 / 5 of the sides 21 and 22. In the sample S2c, the portions of the sides 21 and 22 of the radiating conductor 20 facing the sides 51 and 52 of the first ground conductor G1 are approximately 2 / 3 of the sides 21 and 22. Sample S2d has the same structure as the antenna device 5 shown in Fig. 10, and the sides 21 and 22 of the radiating conductor 20 entirely face the sides 51 and 52 of the first ground conductor G1. The other parameters are the same as those of the above-mentioned sample S1.

[0048] The measurement results are shown in Fig. 15. As shown in Fig. 15, the larger the proportion of the sides 21, 22 of the radiating conductor 20 facing the sides 51, 52 of the first ground conductor G1, the wider the bandwidth in the 24.25 to 29.5 GHz band required by the 5G standard.

[0049] <Example 3> Samples S3a to S3c having the same structure as the antenna device 5 shown in Fig. 10 were fabricated and their antenna characteristics were measured. Samples S3a to S3c are obtained by setting the first distance F between the radiating conductor 20 and the first ground conductor G1 to 0.5 mm, 1 mm, and 1.5 mm, respectively, in the antenna device 5 shown in Fig. 10. The other parameters are the same as those of the above-mentioned sample S1.

[0050] The measurement results are shown in Fig. 16. As shown in Fig. 16, the narrower the first distance F, the wider the bandwidth in the 24.25 to 29.5 GHz band required by the 5G standard. [Explanation of symbols]

[0051] 1~7 Antenna equipment 10 Base material 11 One surface of the substrate 12 Other surface of the substrate 13. Display 20 Radiating conductor 21-24 Edges of the radiating conductor 25,26 Notch 27 Opening area 31,32 Power supply line 41,42 Power supply coupling section 41a Tip of power supply coupling 51, 52 Edges (periphery) of the first ground conductor 60 Auxiliary Pattern 63,64 Parasitic conductor ANT Antenna element P1~P8 ports

Claims

1. A substrate; an antenna element and a first ground conductor provided on one surface side of the base material, the antenna element includes a radiation conductor, a feed line that feeds power to the radiation conductor, and a feed coupling portion connected between the radiation conductor and the feed line; the first ground conductor is disposed at a first distance away from the radiation conductor so as to surround at least a portion of a periphery of the radiation conductor; the feed coupling portion is wider than the feed line and protrudes from the radiation conductor; a tip end of the power supply coupling portion facing the first ground conductor; a second distance between the tip of the power feed coupling portion and the first ground conductor is shorter than the first distance.

2. The antenna device according to claim 1 , further comprising a second ground conductor facing the radiation conductor with the base material interposed therebetween.

3. The antenna device according to claim 1 , wherein the first distance is equal to or less than 0.15 times the wavelength of an electromagnetic wave used in wireless communication.

4. The antenna device according to claim 1 , wherein the radiation conductor has a substantially square shape in a plan view.

5. The antenna device according to claim 4 , wherein the first distance is equal to or less than ⅓ of a length of one side of the radiation conductor.

6. 6. The antenna device according to claim 4, wherein the feed coupling portion protrudes from a center of one of the four sides of the radiation conductor.

7. The antenna device according to claim 4 , wherein the radiation conductor has notches formed by notching two diagonally opposing corners of the radiation conductor.

8. A substrate, an antenna element and a first ground conductor provided on one surface side of the base material, the antenna element includes a radiation conductor, a feed line that feeds power to the radiation conductor, and a feed coupling portion connected between the radiation conductor and the feed line; the first ground conductor is disposed at a first distance away from the radiation conductor so as to surround at least a portion of a periphery of the radiation conductor; the feed coupling portion is wider than the feed line and protrudes from the radiation conductor; The antenna device, wherein the first distance is equal to or less than 0.15 times the wavelength of an electromagnetic wave used for wireless communication.

9. A substrate, an antenna element and a first ground conductor provided on one surface side of the base material, the antenna element includes a radiation conductor, a feed line that feeds power to the radiation conductor, and a feed coupling portion connected between the radiation conductor and the feed line; the first ground conductor is disposed at a first distance away from the radiation conductor so as to surround at least a portion of a periphery of the radiation conductor; the feed coupling portion is wider than the feed line and protrudes from the radiation conductor; The radiation conductor has a substantially square shape in a plan view, The antenna device, wherein the first distance is equal to or less than 1 / 3 of a length of one side of the radiating conductor.

10. The antenna device according to claim 1 , wherein a length of a periphery of the radiation conductor surrounded by the first ground conductor is longer than ¼ of a length of the periphery of the radiation conductor.

11. The antenna device according to claim 1 , comprising a plurality of the feed lines and the feed coupling portions.

12. The antenna device according to claim 1 , wherein the antenna element and the first ground conductor are configured with a mesh-shaped conductor pattern.

13. 13. The antenna device according to claim 1, further comprising at least one parasitic conductor provided on one surface side of the base material and arranged around the radiating conductor so as to be insulated from the radiating conductor.

14. A plurality of the antenna elements are provided, The antenna device according to claim 1 , wherein the first ground conductor is disposed so as to surround at least a portion of a periphery of each of the radiation conductors of the plurality of antenna elements.

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