JP6202746B2 - MIMO antenna device - Google Patents

Description

  The present invention relates to an antenna device for wireless communication, and more particularly to a MIMO antenna device having a plurality of antennas.

  In recent years, in wireless communication networks, a technique called MIMO (Multiple Input Multiple Output) has been developed, in which a plurality of antennas are combined to transmit and receive data and pseudo-expand the usable frequency band. In a system using such a technique, a MIMO antenna apparatus in which a plurality of antennas capable of transmitting and receiving at the same frequency are arranged in the vicinity of each other is used.

  For a MIMO antenna apparatus in which a plurality of antennas are arranged in the vicinity of each other, it is required to ensure necessary and sufficient isolation between antennas. Recently, there is also a demand for downsizing the MIMO antenna apparatus.

  In response to such a requirement, Patent Document 1 proposes an antenna device that has two antennas corresponding to the same frequency band and can be easily designed and obtain good antenna characteristics. An antenna device according to Patent Document 1 will be described with reference to FIG.

  The antenna device 900 includes an inverted-F antenna element 910A having a short stub 911A and a power feeding portion 912A connected to the ground element 920, and is connected to the ground element 920 and spaced apart from the short stub 911A. And an inverted F-type antenna element 910B having a short stub 911B and a power feeding portion 912B. The ground element 920 includes a linear portion 901 between one end 911A1 that is a connection portion between the short stub 911A and the ground element 920 and one end 911B1 that is a connection portion between the short stub 911B and the ground element 920.

  In the antenna device 900, it is possible to easily design and obtain good antenna characteristics by appropriately setting the size of the distance A between the short stub 911A of the antenna element 910A and the short stub 911B of the antenna element 910B. The antenna device 900 can be provided.

JP 2012-231417 A

  However, the antenna device 900 disclosed in Patent Document 1 can be downsized, but the short stub 911A and the short stub 911B having a low electric field strength are close to each other, and a portion having a relatively strong electric field strength is close to the antenna device 900. Therefore, the effect on the isolation characteristics between the antennas is weak, and it is difficult to obtain the required isolation between the antennas.

  The present invention has been made in view of such a state of the prior art, and an object of the present invention is to provide a MIMO antenna apparatus that is suitable for downsizing and that can obtain the required isolation characteristics between antennas. It is in.

In order to solve this problem, the MIMO antenna apparatus of the present invention includes a first antenna and a second antenna that transmit and / or receive signals in the same frequency band, and the first antenna and the second antenna, respectively. And a ground pattern, a first feeding point, a second feeding point, and a grounding point connected to the ground pattern, and the first antenna and the first feeding point. Each of the second antennas constitutes an inverted F-type antenna, and the first antenna has a first feeding part connected to the first feeding point and a first shorting part connected to the ground point, A MIMO antenna apparatus having a second feeding part connected to the second feeding point and a second shorting part connected to the ground point, wherein the second antenna is a first antenna, the second antenna, The first open end portion including the open end of the first antenna and the open end of the second antenna are symmetrical with respect to a virtual center line passing between the first short circuit portion and the second short circuit portion. And a second open end including a slit formed between the first antenna and the second antenna so as to sandwich the virtual center line, and the first antenna and The second antenna has a first proximity facing portion and a second proximity facing portion that are closely facing each other across the slit, and the first proximity facing portion and the second proximity facing portion are The first short circuit portion and the second short circuit portion are located on the first open end side or the second open end side from the respective central portions of the first antenna and the second antenna. And the first antenna and the second antenna. And antenna is formed by a single metal plate, it has a characteristic that.

In the MIMO antenna apparatus configured as described above, a slit is formed across a virtual center line between the first antenna and the second antenna, and a first proximity facing portion that is opposed to and close to the slit across the slit. And the second proximity facing portion is positioned closer to the first open end portion or the second open end portion than the central portion of each of the first antenna and the second antenna, so that the electric field strength is relatively strong. The parts can be closely opposed. As a result, the effect on the isolation characteristics between antennas can be strengthened. Therefore, it is suitable for downsizing, and the required isolation characteristics between antennas can be obtained. Further, in the MIMO antenna apparatus configured as described above, the relative positional accuracy between the first antenna and the second antenna can be increased, so that the designed characteristics are easily obtained.

  In the above configuration, the electrical length obtained by the outer periphery forming the slit is ½ of the wavelength of the signal to be transmitted or received.

  In the MIMO antenna apparatus configured as described above, the electrical length obtained by the outer periphery forming the slit is set to ½ of the wavelength of the signal to be transmitted or received, so that the first antenna and the second antenna are separated from each other. The slit can be made the optimum size. Therefore, the maximum isolation between antennas can be obtained.

  In the above configuration, the first short-circuit portion, the second short-circuit portion, the first power feeding portion, the second power feeding portion, the first open end portion, and the second open end portion Is provided perpendicular to the first proximity facing portion and the second proximity facing portion.

  In the MIMO antenna apparatus configured as described above, since the first antenna and the second antenna are three-dimensionally formed, the size of the MIMO antenna apparatus in plan view can be reduced. Therefore, it is optimal for miniaturization.

  Further, in the above configuration, a first adjustment unit that adjusts the electrical length of the first antenna is provided at a position adjacent to the first open end in parallel, and is positioned adjacent to the second open end in parallel. The second adjustment unit for adjusting the electrical length of the second antenna is provided.

  In the MIMO antenna apparatus configured as described above, when the MIMO antenna apparatus is to be operated not only in the first band but also in the second band having a higher frequency than the first band, the first adjustment unit and the first open end Since the degree of capacitive coupling between the second adjustment unit and between the second adjustment unit and the second open end can be adjusted, the antenna length in the second band can be easily adjusted. .

  In the above configuration, the insulating substrate is provided with a first connection land to which the open end of the first antenna is connected and a second connection land to which the open end of the second antenna is connected. The first connection land faces the first adjustment portion, and the second connection land faces the second adjustment portion.

  In the MIMO antenna apparatus configured as described above, the first connection land faces the first adjustment unit, and the second connection land faces the second adjustment unit. Each can function as a part of the first antenna and the second antenna. Therefore, the size of the MIMO antenna device can be further reduced.

  In the MIMO antenna apparatus of the present invention, a slit is formed across the virtual center line between the first antenna and the second antenna, and the first proximity facing portion and the second facing each other in close proximity across the slit. The proximity facing portion is positioned closer to the first open end or the second open end than the center of each of the first antenna and the second antenna. Can be opposed. As a result, the effect on the isolation characteristics between antennas can be strengthened. Therefore, it is suitable for downsizing, and the required isolation characteristics between antennas can be obtained.

1 is an external perspective view of a MIMO antenna device according to a first embodiment of the present invention. It is an expansion perspective view of an insulating substrate. It is an expansion perspective view of a MIMO antenna device. It is the top view, front view, and side view of a MIMO antenna apparatus. An antenna current path in the 2.4 GHz band of the MIMO antenna apparatus is shown. An antenna current path in a 5 GHz band of a MIMO antenna apparatus is shown. It is a graph which shows the return loss characteristic in 2.4 GHz band of a MIMO antenna apparatus, and the isolation characteristic between antennas. It is an expansion perspective view of the MIMO antenna apparatus which concerns on 2nd Embodiment. It is the top view, front view, and side view of a MIMO antenna apparatus. It is a top view of the MIMO antenna apparatus which concerns on a prior art example.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. In this specification, unless otherwise specified, the X1 side of each drawing is described as the right side, the X2 side as the left side, the Y1 side as the back side, the Y2 side as the near side, the Z1 side as the upper side, and the Z2 side as the lower side. To do.

  First, the external shape of the MIMO antenna device 100 according to the embodiment, the configuration of the insulating substrate 4, and the structure of each of the first antenna 10 and the second antenna 20 will be described with reference to FIGS.

  FIG. 1 is a perspective view showing an appearance of the MIMO antenna apparatus 100 according to the first embodiment, and FIG. 2 is an enlarged perspective view showing the configuration of the insulating substrate 4. 3 is an enlarged perspective view of the MIMO antenna apparatus 100, and FIG. 4 is a plan view of the MIMO antenna apparatus 100, (b) a front view, (c) a rear view, (d) a right side view, and (E) It is a left view.

  As shown in FIG. 1, the MIMO antenna apparatus 100 includes a first antenna 10 and a second antenna 20 that are three-dimensionally configured with metal plates, and an insulating substrate 4 on which the first antenna 10 and the second antenna 20 are placed. And is composed of. The first antenna 10 and the second antenna 20 are placed along the short side on the back side (Y1 side) of the rectangular insulating substrate 4, and a part of each of the first antenna 10 and the second antenna 20. Is fixed to the insulating substrate 4. A rectangular ground pattern 8 is formed on the front side (Y2 side) of the insulating substrate 4. Similarly, the communication circuit 60 is mounted on the front side (Y2 side), and the first antenna 10 and the second antenna 20 are connected to the communication circuit 60, respectively. The communication circuit 60 includes an integrated circuit (not shown) in which a wireless LAN circuit is incorporated and other electronic components (not shown), and has a high-frequency signal input / output terminal (not shown). . The communication circuit 60 may be configured not only on the upper surface (Z1 side) of the insulating substrate 4 but also on the lower surface (Z2 side) or the inner layer surface of the insulating substrate 4.

  As shown in FIG. 2, on the insulating substrate 4, the ground pattern 8, the ground point 3 connected to the ground pattern 8, the first feeding point 1, the second feeding point 2, and the first connection are provided. A land 6 and a second connection land 7 are provided.

  The grounding point 3 is provided at a substantially central position on one short side of the rectangular ground pattern 8. The first feeding point 1 and the second feeding point 2 are provided at positions on both sides of the ground point 3 and are respectively connected to the high-frequency signal input / output terminals (not shown) of the communication circuit 60 described above. Yes. A first antenna 10 is attached to the first feeding point 1 and the grounding point 3, and a second antenna 20 is attached to the second feeding point 2 and the grounding point 3. A first antenna 10 is attached to the first connection land 6, and a second antenna 20 is attached to the second connection land 7.

  A state in which the first antenna 10 and the second antenna 20 are attached to the insulating substrate 4 is shown in FIG. The first antenna 10 and the second antenna 20 constitute an inverted F-type antenna, respectively, and are configured to transmit and / or receive signals in the same frequency band used in the wireless LAN. In addition, it is configured to be able to transmit and / or receive a 2.4 GHz band signal which is a first band and a 5 GHz band signal which is a second band having a higher frequency than the first band. . The 2.4 GHz band refers to 2.40 GHz to 2.49 GHz, and the 5 GHz band refers to 5.17 GHz to 5.83 GHz.

  The first antenna 10 has a first feeding part 11 and a first short-circuit part 12, and the second antenna 20 has a second feeding part 21 and a second short-circuit part 22, and the first antenna 10 and the second antenna. 20 is configured symmetrically with respect to a virtual center line R <b> 1 passing between the first short-circuit portion 12 and the second short-circuit portion 22. In addition, the first antenna 10 and the second antenna 20 are respectively fed from the communication circuit 60 through the first feeding point 1 and the second feeding point 2.

  The first power supply portion 11 has a first power supply end 11a as a tip portion formed in parallel to the insulating substrate 4, and is electrically connected to the first power supply point 1 by solder or the like, and also the insulating substrate 4 It is fixed to. The second power feeding portion 21 also has a second power feeding end 21a that is the tip of the second power feeding portion 21 formed in parallel to the insulating substrate 4, and is electrically connected to the second power feeding point 2 by solder or the like, and also the insulating substrate 4 It is fixed to.

  As shown in FIGS. 3, 4A, and 4B, in the MIMO antenna apparatus 100, the first short-circuit portion 12 and the second short-circuit portion 22 are connected across the virtual center line R1. In addition, the first antenna 10 and the second antenna 20 are formed of a single metal plate. As shown in FIG. 3, the first short-circuit portion 12 and the second short-circuit portion 22 are formed such that the first short-circuit end 12 a and the second short-circuit end 22 a that are common tip portions are formed in parallel to the insulating substrate 4. Then, it is electrically connected to the ground point 3 by solder or the like and is fixed to the insulating substrate 4.

  As shown in FIGS. 3, 4 (a), and 4 (b), the first power supply unit 11, the second power supply unit 21, the first short circuit unit 12, and the second short circuit unit 22 are connected to the insulating substrate 4. These upper ends are connected to a first top plate portion 16 and a second top plate portion 26 that are formed in parallel to the insulating substrate 4. As shown in FIG. 4A, the first top plate portion 16 and the second top plate portion 26 are each formed in a meander shape.

  As shown in FIGS. 3, 4A, 4D, and 4E, the first top plate portion 16 and the second top plate portion 26 formed in a meander shape, respectively, The first open end 13 and the second open end 23 are formed at the ends, and the first open end 13 and the second open end 23 are formed by being bent perpendicularly to the direction of the insulating substrate 4. . The first open end 13 and the second open end 23 have a first open end 13a and a second open end 23a, respectively, and are soldered to the first connection land 6 and the second connection land 7 on the insulating substrate 4. Are electrically connected and fixed to the insulating substrate 4. The first open end portion 13 including the first open end 13a of the first antenna 10 and the second open end portion 23 including the second open end 23a of the second antenna 20 are disposed apart from each other.

  The MIMO antenna apparatus 100 forms a slit 19 across the virtual center line R1 between the first antenna 10 and the second antenna 20, as shown in FIGS. 3, 4A, and 4C. ing. The slit 19 is formed by combining the meander shapes of the first antenna 10 and the second antenna 20. The electrical length L1 obtained by the outer periphery forming the slit 19 (indicated by a broken line in FIGS. 4A and 4C) is determined by the frequency of the signal to be transmitted or received, and the magnitude of the electrical length L1. As a result, it is possible to set the frequency at which the isolation between the antennas is best. The details will be described later.

  Each of the first top plate portion 16 and the second top plate portion 26 includes a first proximity facing portion 14 and a second proximity facing portion 24 that face each other with a slit 19 therebetween. Then, as shown in FIG. 4A, the first proximity facing portion 14 and the second proximity facing portion 24 are configured such that the center portion 16a of the path or the second top plate portion 26 in the first top plate portion 16 having a meander shape. Is located closer to the first open end 13 or the second open end 23 than the center 26a of the path. In other words, the first proximity facing portion 14 and the second proximity facing portion 24 are respectively connected to the first open end 13a or the second open end of the first antenna 10 and the second antenna 20 from the first short-circuited end 12a or the second short-circuited end 22a. It is located on the first open end 13 side or the second open end 23 side from the center in the path to the open end 23a. Accordingly, the first antenna 10 and the second antenna 20 are close to each other and have relatively strong electric field strengths. And the magnitude | size of the separation distance D1 between the 1st proximity facing part 14 and the 2nd proximity facing part 24 which are shown to Fig.4 (a) is combined with the electrical length L1 obtained by the outer periphery which forms the slit 19. FIG. The frequency is determined in consideration of the isolation between the antennas in the frequency of the signal to be transmitted or received, particularly in the frequency of the 2.4 GHz band which is the first band.

  As shown in FIGS. 3, 4 (c), 4 (d), and 4 (e), the MIMO antenna device 100 further includes a first adjustment unit 15, a first side plate unit 17, and a second adjustment unit 25. The second side plate portion 27 is provided. The first adjustment unit 15 is formed by being bent perpendicularly in the direction of the insulating substrate 4 from the right end (X1 side) end of the first top plate unit 16, and the second adjustment unit 25 is the second top plate unit 26. It is formed by being bent perpendicularly in the direction of the insulating substrate 4 from the left end (X2 side). The first side plate portion 17 is formed by being bent perpendicularly from the end on the back side (Y1 side) of the first top plate portion 16 in the direction of the insulating substrate 4, and the second side plate portion 27 is formed by the second top plate portion 27. It is formed by being bent perpendicularly in the direction of the insulating substrate 4 from the end on the back side (Y1 side) of the plate portion 26. Therefore, the 1st short circuit part 12, the 2nd short circuit part 22, the 1st electric power feeding part 11, the 2nd electric power feeding part 21, the 1st open end part 13, the 2nd open end part 23, and the 1st adjustment part 15, the first side plate portion 17, the second adjustment portion 25, and the second side plate portion 27 with respect to the first proximity facing portion 14 of the first antenna 10 and the second proximity facing portion 24 of the second antenna 20. Will be provided vertically.

  As shown in FIG. 4 (d), the first adjustment unit 15 is provided at a position adjacent to the first open end 13 in parallel with the first adjustment end 25, and the second adjustment unit 25 is illustrated in FIG. 4 (e). As shown, it is provided at a position adjacent to the second open end 23 described above in parallel. The first adjustment unit 15 and the second adjustment unit 25 operate in the 5 GHz band, which is a second band having a higher frequency than the 2.4 GHz band, which is the first band, so that the antenna length in the 5 GHz band is adjusted. Is provided. By providing the 1st adjustment part 15 and the 2nd adjustment part 25, between the 1st adjustment part 15 and the 1st open end part 13, and between the 2nd adjustment part 25 and the 2nd open end part 23, respectively The degree of capacitive coupling can be adjusted. Therefore, the antenna length in the second band, that is, the 5 GHz band can be easily adjusted.

  The first side plate portion 17 and the second side plate portion 27 are relatively close to the first open end portion 13 and the second open end portion 23 of the first top plate portion 16 and the second top plate portion 26, respectively. , Provided to increase the conductor width at that position. By increasing the conductor width at this position, a capacitance can be provided between the first open end 13 side and the second open end 23 side of the first antenna 10 and the second antenna 20 and the ground. it can. As a result, the respective resonance frequencies in the second band, that is, the 5 GHz band, are shifted downward, and as a result, the MIMO antenna apparatus 100 can be reduced in size.

  Next, the operation of the MIMO antenna apparatus 100 according to the embodiment will be described with reference to FIGS.

  FIG. 5 shows an antenna current path in the 2.4 GHz band of the MIMO antenna apparatus 100, and FIG. 6 shows an antenna current path in the 5 GHz band. FIG. 7 is a graph showing the return loss characteristic and the inter-antenna isolation characteristic in the 2.4 GHz band of the MIMO antenna apparatus 100. Here, FIG. 7A shows the case where the electrical length L1 obtained by the outer periphery forming the slit 19 is smaller than ½ of the wavelength (λ) of the transmitted or received signal, that is, L1 <λ. FIG. 7 (b) shows the characteristics when L1 = λ / 2, and FIG. 7 (c) shows the characteristics when L1> λ / 2.

  As shown in FIG. 5, the current path J1 of the antenna current in the 2.4 GHz band of the first antenna 10 is a path starting from the first short-circuited end 12a and ending at the first open end 13a. Further, the current path J2 of the antenna current in the 2.4 GHz band of the second antenna 20 is a path starting from the second short-circuited end 22a and ending at the second open end 23a. At the first short-circuited end 12a and the second short-circuited end 22a, the antenna current is maximized and the electric field strength, that is, the antenna voltage is minimized, and at the first open end 13a and the second open end 23a, the antenna current is maximized. And the electric field strength, that is, the antenna voltage is maximum. Therefore, the first proximity facing portion 14 and the second proximity located on the first open end 13 side or the second open end 23 side from the central portions 16a and 26a of the first antenna 10 and the second antenna 20. As described above, the facing portion 24 is disposed at a position where the electric field strength is relatively strong. Therefore, a stronger effect on the isolation characteristics between antennas can be expected. The length of each of the current path J1 and the current path J2 is set to a length corresponding to the electrical length of the first antenna 10 and the second antenna 20 in the 2.4 GHz band.

  As shown in FIG. 6, there are a plurality of current paths K1 of the first antenna 10 and a current path K2 of the second antenna 20 in the 5 GHz band, and their operating states are different from those in the 2.4 GHz band. . The starting points of the current path K1 and the current path K2 of the first antenna 10 and the second antenna 20 are considered to be near the virtual center line R1. As described above, since the first antenna 10 and the second antenna 20 have a length corresponding to the electrical length in the 2.4 GHz band, the first antenna 10 and the second antenna 20 in the high-frequency 5 GHz band. A point where the electric field is minimized in the middle of each conductor of the antenna 20, that is, a point where the antenna voltage becomes approximately 0 V occurs. That point also exists in the vicinity of the first proximity facing portion 14 and the second proximity facing portion 24 in the vicinity of the virtual center line R1. In other words, the position of the point where the antenna voltage becomes approximately 0 V in the middle of the conductor of each of the first antenna 10 and the second antenna 20 is the first proximity facing portion 14 and the second proximity facing portion near the virtual center line R1. It is set to be around 24.

  Therefore, the starting points of the current path K1 and the current path K2 in the 5 GHz band of the first antenna 10 and the second antenna 20 are the first proximity facing portion 14 and the second proximity facing portion in addition to the first short-circuit portion 12 and the second short-circuit portion 22. 24, and the end points of the current path K <b> 1 and the current path K <b> 2 are at the respective ends of the first open end 13, the first adjuster 15, the second open end 23, and the second adjuster 25. The length of each of the current path K1 and the current path K2 is set to a length corresponding to the electrical length of the first antenna 10 and the second antenna 20 in the 5 GHz band.

  As described above, the MIMO antenna apparatus 100 has the slit 19 formed between the first antenna 10 and the second antenna 20, and the slit 19 indicated by a broken line in FIGS. 4 (a) and 4 (c). The electrical length L1 obtained by the outer periphery forming the is determined by the frequency of the signal transmitted or received. The frequency at which the isolation between the antennas is best can be set by the electrical length L1. The return loss characteristic and the antenna isolation characteristic can be improved relatively easily when the frequency is high, but the improvement becomes difficult as the frequency is lowered. Therefore, in the MIMO antenna device 100, the electrical length L1 obtained by the outer periphery forming the slit 19 is set to improve the antenna characteristics of the 2.4 GHz band instead of the 5 GHz band. Therefore, the present invention is not particularly applied in the 5 GHz band.

  7 (a), 7 (b), and 7 (c) show the 2.4 GHz band when the electrical length L1 obtained by the outer periphery where the slit 19 of the MIMO antenna apparatus 100 is changed is changed. The return loss characteristic and the isolation characteristic between antennas are shown.

  As shown in FIG. 7A, when the electrical length L1 obtained by the outer periphery forming the slit 19 is set to be smaller than ½ of the wavelength of the 2.4 GHz band signal, that is, L1 <λ / 2. In this case, the best frequency of the isolation characteristic between antennas is in the vicinity of 2.6 GHz, and deteriorates in the 2.4 GHz band. Therefore, it can be seen that the electrical length L1 is too short.

  Further, as shown in FIG. 7C, when the electrical length L1 obtained by the outer periphery forming the slit 19 is set to be larger than ½ of the wavelength of the 2.4 GHz band signal, that is, L1> λ When the frequency is / 2, the best frequency of the isolation characteristic between antennas is in the vicinity of 2.3 GHz, and in this case, the frequency is deteriorated in the 2.4 GHz band. Therefore, it can be seen that the electrical length L1 is too long.

  As shown in FIG. 7B, when the electrical length L1 obtained by the outer periphery forming the slit 19 is set to ½ of the wavelength of the 2.4 GHz band signal, that is, L1 = λ / When the frequency is 2, the best frequency of the isolation characteristic between antennas is between 2.4 GHz and 2.5 GHz, and shows the best value in the 2.4 GHz band. Also, the return loss characteristic shows a good value in this band. Therefore, it can be seen that L1 = λ / 2 is optimal as the electrical length L1.

  As shown in FIG. 7A, FIG. 7B, and FIG. 7C, the frequency at which the inter-antenna isolation is best is set by the electrical length L1 obtained by the outer periphery forming the slit 19. can do. Further, if the electrical length L1 obtained by the outer periphery forming the slit 19 is set to be ½ of the wavelength of the signal to be transmitted or received, the inter-antenna isolation can be maximized.

  As described above, in the MIMO antenna device 100, the slit 19 is formed with the virtual center line R1 between the first antenna 10 and the second antenna 20 interposed therebetween. Then, the first proximity facing portion 14 and the second proximity facing portion 24 that are opposed to each other with the slit 19 therebetween are arranged at the first open end portion from the central portion of each of the first antenna 10 and the second antenna 20. Since it is located on the side of 13 or the side of the second open end 23, it is possible to make the portions having a relatively strong electric field strength close to each other. As a result, the effect on the isolation characteristics between antennas can be strengthened. Therefore, it is suitable for downsizing, and the required isolation characteristics between antennas can be obtained.

  In addition, since the electrical length L1 obtained by the outer periphery forming the slit 19 is ½ of the signal wavelength, the slit 19 separating the first antenna 10 and the second antenna 20 is set to an optimum size. can do. Therefore, the maximum isolation between antennas can be obtained.

  Moreover, since the 1st antenna 10 and the 2nd antenna 20 were formed with the metal plate of 1 sheet, the relative positional accuracy of the 1st antenna 10 and the 2nd antenna 20 can be made high. For this reason, it is easy to produce the characteristics as designed.

  Further, the first short-circuit portion 12, the second short-circuit portion 22, the first power feeding portion 11, the second power feeding portion 21, the first open end portion 13, and the second open end portion 23 are connected to the first antenna. 10 first proximity facing portions 14 and the second proximity facing portion 24 of the second antenna 20 are provided perpendicularly. Therefore, since the first antenna 10 and the second antenna 20 can be formed in a three-dimensional manner, the size of the MIMO antenna device 100 in plan view can be reduced. Therefore, it is optimal for miniaturization.

  In addition, when the MIMO antenna apparatus 100 is to be operated in a second band having a frequency higher than the first band in addition to the first band, the first adjustment unit 15 and the second adjustment unit 25 are provided. The degree of capacitive coupling between the first adjusting unit 15 and the first open end 13 and between the second adjusting unit 25 and the second open end 23 can be adjusted. Therefore, the antenna length in the second band can be easily adjusted.

  In addition, since the first connection land 6 faces the first adjustment unit 15 and the second connection land 7 faces the second adjustment unit 25, the first connection land 6 and the second connection land 7 are respectively connected to the first adjustment land 15. It can function as part of the antenna 10 and the second antenna 20. Therefore, the size of the MIMO antenna device 100 can be further reduced.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings.

  The structures of the first antenna 30 and the second antenna 40 of the MIMO antenna apparatus 200 according to the second embodiment will be described with reference to FIGS.

  FIG. 8 is an enlarged perspective view of the MIMO antenna apparatus 200, and FIG. 9 is a (a) plan view, (b) front view, (c) rear view, (d) right side view, and FIG. (E) It is a left view.

  Since the structural difference between the MIMO antenna apparatus 100 and the MIMO antenna apparatus 200 described above is only the first short-circuit portion 12 and the second short-circuit portion 22 in the MIMO antenna apparatus 100, they are structurally or functionally identical. The same reference numerals are used for these parts. In addition, description of common portions may be omitted.

  As shown in FIG. 8, the MIMO antenna apparatus 200 includes a first antenna 30 and a second antenna 40 that are three-dimensionally configured with metal plates, and an insulating substrate 5 on which the first antenna 30 and the second antenna 40 are placed. And is composed of. The first antenna 30 and the second antenna 40 are placed on one short side (Y1 side) of the rectangular insulating substrate 5, and a part thereof is connected and fixed on the insulating substrate 5.

  Two grounding points 9 are arranged side by side at a substantially central position of one short side of the ground pattern 8 having a rectangular shape. The first feeding point 1 and the second feeding point 2 are provided at positions on both sides of the ground point 9 and are respectively connected to the high-frequency signal input / output terminals (not shown) of the communication circuit 60 described above. Yes. A first antenna 30 is attached to the right grounding point 9 and the first feeding point 1, and a second antenna 40 is attached to the left grounding point 9 and the second feeding point 2. Further, the first antenna 30 is attached to the first connection land 6, and the second antenna 40 is attached to the second connection land 7.

  The first antenna 30 and the second antenna 40 constitute an inverted F-type antenna, respectively, and the first antenna 30 and the second antenna 40 respectively transmit signals in the same frequency band used in the wireless LAN. It is configured to transmit and / or receive. The frequencies to be handled are formed so that a 2.4 GHz band signal and a 5 GHz band signal can be transmitted and received, respectively. The first antenna 30 and the second antenna 40 are supplied with power from the communication circuit 60 described above via the first feeding point 1 and the second feeding point 2, respectively.

  The first antenna 30 has a first feeding part 11 connected to the first feeding point 1 and a first short-circuit part 32 connected to the grounding point 9 on the right side, and the second antenna 40 is connected to the second feeding point 2. And the second short-circuit portion 42 connected to the grounding point 9 on the left side. Further, the first antenna 30 and the second antenna 40 are configured symmetrically with respect to a virtual center line R <b> 2 passing between the first short-circuit portion 12 and the second short-circuit portion 22.

  As shown in FIG. 8, FIG. 9A, and FIG. 9B, the MIMO antenna apparatus 200 includes a first short circuit part 32 and a second short circuit part 42 separated from each other, The second antenna 40 is formed by a separate metal plate. This is the only structural difference between the MIMO antenna apparatus 100 and the MIMO antenna apparatus 200. As shown in FIG. 8 and FIG. 9A, the first short-circuit portion 32 and the second short-circuit portion 42 are configured such that the first short-circuit end 32 a and the second short-circuit end 42 a which are the respective front end portions are in relation to the insulating substrate 5. Are connected to the two grounding points 9 by solder or the like and fixed to the insulating substrate 5.

  The MIMO antenna apparatus 200 forms a slit 39 between the first antenna 30 and the second antenna 40 as shown in FIGS. 8, 9A, 9B, and 9C. ing. The slit 39 is formed by combining the meander shapes of the first antenna 30 and the second antenna 40. The electrical length L2 obtained by the outer periphery forming the slit 39 (shown by broken lines in FIGS. 9A, 9B, and 9C) is determined by the frequency of the signal transmitted or received. The frequency at which the isolation between the antennas is best can be set according to the size of the electrical length L2.

  The effect of the electrical length L2 obtained by the outer periphery of the slit 39 of the MIMO antenna device 200 on the isolation between antennas is the isolation between the antennas due to the size of the electrical length L2 in the MIMO antenna device 100 shown in FIG. Since this is equivalent to the effect of, the description thereof is omitted. In the MIMO antenna apparatus 200, since the first antenna 30 and the second antenna 40 can be physically separated by the slit 39, the inter-antenna isolation can be further improved as compared with the MIMO antenna apparatus 100. Can do.

  As described above, in the MIMO antenna apparatus 200, the first antenna 30 and the second antenna 40 are formed of separate metal plates, so that the first antenna 30 and the second antenna 40 can be physically separated. Therefore, greater isolation between antennas can be obtained.

  As described above, the MIMO antenna apparatus of the present invention forms a slit across the virtual center line between the first antenna and the second antenna, and faces the first antenna that is in close proximity across the slit. Since the proximity facing portion and the second proximity facing portion are positioned closer to the first open end portion or the second open end portion than the central portions of the first antenna and the second antenna, Relatively strong parts can be made to face each other. As a result, the effect on the isolation characteristics between antennas can be strengthened. Therefore, it is suitable for downsizing, and the required isolation characteristics between antennas can be obtained.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the present invention, a metal plate is used as the constituent material of the antenna, but a conductor pattern formed on an insulating substrate may be used as the constituent material of the antenna.

DESCRIPTION OF SYMBOLS 1 1st feeding point 2 2nd feeding point 3 Grounding point 4 Insulating substrate 5 Insulating substrate 6 1st connection land 7 2nd connection land 8 Ground pattern 9 Grounding point 10 1st antenna 11 1st feeding part 11a 1st feeding end 12 First short-circuit portion 12a First short-circuit end 13 First open end portion 13a First open end 14 First proximity facing portion 15 First adjustment portion 16 First top plate portion 17 First side plate portion 19 Slit 20 Second antenna 21 First 2 power supply part 21a 2nd power supply end 22 2nd short circuit part 22a 2nd short circuit end 23 2nd open end part 23a 2nd open end 24 2nd proximity facing part 25 2nd adjustment part 26 2nd top plate part 27 2nd side plate Part 30 First antenna 32 First short-circuit part 32a First short-circuit end 39 Slit 40 Second antenna 42 Second short-circuit part 42a Second short-circuit end 60 Communication circuit 100 MIMO antenna apparatus 200 MI O antenna device L1 electrical length L2 electrical length R1 imaginary center line R2 imaginary center line

Claims (5)

A first antenna and a second antenna that respectively transmit and / or receive signals in the same frequency band; and an insulating substrate on which the first antenna and the second antenna are mounted,
The insulating substrate is provided with a ground pattern, a first feeding point, a second feeding point, and a ground point connected to the ground pattern,
Each of the first antenna and the second antenna constitutes an inverted F-type antenna, and the first antenna is connected to the first feed point connected to the first feed point and the first ground point connected to the ground point. A MIMO antenna apparatus having a short-circuit portion, the second antenna having a second feed portion connected to the second feed point and a second short-circuit portion connected to the ground point,
The first antenna and the second antenna are axisymmetric with respect to a virtual center line passing between the first short-circuit portion and the second short-circuit portion,
A first open end including the open end of the first antenna and a second open end including the open end of the second antenna are arranged apart from each other;
A slit is formed between the first antenna and the second antenna with the virtual center line interposed therebetween,
The first antenna and the second antenna have a first proximity facing portion and a second proximity facing portion facing each other in close proximity with the slit, and the first proximity facing portion and the first antenna 2 adjacent facing portions are located on the first open end side or the second open end side from the central portion of each of the first antenna and the second antenna ,
The first short circuit part and the second short circuit part are connected, and the first antenna and the second antenna are formed by a single metal plate .
A MIMO antenna apparatus characterized by that.   The MIMO antenna apparatus according to claim 1, wherein an electrical length obtained by an outer periphery forming the slit is ½ of a wavelength of the signal to be transmitted or received. The first short-circuit portion, the second short-circuit portion, the first power feeding portion, the second power feeding portion, the first open end portion, and the second open end portion are opposed to the first proximity. The MIMO antenna apparatus according to claim 1 , wherein the MIMO antenna apparatus is provided perpendicularly to a portion and the second proximity facing portion. A first adjustment unit for adjusting the electric length of the first antenna is provided at a position adjacent to the first open end in parallel, and the electric power of the second antenna is set at a position adjacent to the second open end in parallel. The MIMO antenna apparatus according to claim 3 , wherein a second adjustment unit that adjusts the length is provided. The insulating substrate is provided with a first connection land to which the open end of the first antenna is connected, and a second connection land to which the open end of the second antenna is connected,
5. The MIMO antenna apparatus according to claim 4 , wherein the first connection land faces the first adjustment unit, and the second connection land faces the second adjustment unit. 6.