Antenna equipment

Abstract

The present invention provides an antenna device that suppresses the complexity of the mounting process on the circuit board. [Solution] An antenna device comprising a first surface and a second surface which is the back surface of the first surface, an element arrangement section in which radiating elements are arranged on the side of the first surface and a ground layer is arranged on the side of the second surface, and a power supply section in which one end is connected to the radiating elements and the other end protrudes from the second surface and supplies power to the radiating elements, characterized in that the tip of the other end protrudes in the direction that the second surface faces more than the ground layer.

Description

Technical Field

[0004] ,

[0005] ,

[0001] The present invention relates to an antenna device.

Background Art

[0002] Conventionally, various forms of antenna devices have been developed according to the purpose. For example, Patent Document 1 discloses an array antenna in which a plurality of antennas are arranged in an array. In this array antenna, beamforming is performed by giving a phase difference to each antenna, and a wide-angle radiation directivity is obtained.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When both the end of the power supply unit that supplies power to the radiation element and the ground layer in the antenna device are provided on the same side of the surface that defines the antenna device, on the circuit board on which the antenna device is mounted, pads connected to the power supply unit and pads connected to the ground layer are provided at positions facing the power supply unit and the ground layer. However, since the height of the bumps placed on the pads connected to the power supply unit tends to be lower than the height of the bumps placed on the pads connected to the ground layer, it is necessary to separately perform processes such as placing bumps with a larger diameter on the pads connected to the power supply unit than the bumps placed on the pads connected to the ground layer, and there is a problem that the mounting process becomes complicated. For this reason, in an antenna device in which the end of the power supply unit and the ground layer are provided on the same side, a technique capable of suppressing the complication of the mounting process has been desired. Note that the array antenna of Patent Document 1 does not consider at all suppressing the complication of the mounting process.

[0005] The present invention has been made to solve at least some of the above-mentioned problems, and aims to provide an antenna device that suppresses the complexity of the mounting process on a circuit board. [Means for solving the problem]

[0006] The present invention has been made to solve at least some of the above-mentioned problems and can be realized in the following forms.

[0007] (1) According to one embodiment of the present invention, an antenna device is provided. This antenna device includes a first surface and a second surface which is the back surface of the first surface, and comprises an element arrangement section in which a radiating element is arranged on the side of the first surface and a ground layer is arranged on the side of the second surface, and a power supply section in which one end is connected to the radiating element and the other end protrudes from the second surface and supplies power to the radiating element, wherein the tip of the other end protrudes in a direction that faces the second surface more than the ground layer.

[0008] In this configuration, the tip of the other end of the power supply section, which is the end connected to the pad, protrudes in a direction that faces the second surface, rather than the ground layer. Therefore, on the circuit board on which the antenna device is mounted, even if a bump of the same diameter as the bump placed on the pad connected to the ground layer is placed on the pad connected to the power supply section, the pad connected to the power supply section and the power supply section can be connected. In other words, since it is not necessary to place a bump with a larger diameter than the bump placed on the pad connected to the ground layer on the pad connected to the power supply section, the complexity of the mounting process on the circuit board can be suppressed.

[0009] (2) In the antenna device according to the above embodiment, the distance along the direction from the ground layer to the tip may be 10 μm or more and less than 40 μm. With this configuration, when a bump of the same diameter as the bump placed on the pad connected to the ground layer is placed on the pad connected to the power supply unit, the connection between the pad connected to the power supply unit and the power supply unit can be ensured with high precision.

[0010] (3) In the antenna device according to the above embodiment, when viewed from the opposite direction of the second surface, the other end may be located in a region of the second surface that is closer to the center and is similar in shape to a region with an area of ​​50% of the cross-sectional area of ​​the outer shape of the antenna device. In this configuration, the other end of the power supply section that protrudes in the direction the second surface faces is positioned relatively close to the center of the second surface, thus reducing the likelihood of impedance mismatch. As a result, high-frequency signals can be supplied to the power supply section from the circuit board while suppressing the loss of high-frequency signals.

[0011] Furthermore, the present invention can be realized in various forms, for example, as an antenna device, a communication device, or a component or device comprising these. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of an antenna device according to an embodiment of the present invention. [Figure 2] This is a cross-sectional view of the antenna device. [Figure 3] This is an explanatory diagram conceptually showing the position of the edges on the reverse side. [Figure 4] This is a cross-sectional view of a circuit board. [Figure 5] This is an explanatory diagram showing a circuit board with bumps installed. [Figure 6] This is an explanatory diagram showing the antenna device mounted on a circuit board. [Modes for carrying out the invention]

[0013] <Embodiment> Figure 1 is a perspective view of an antenna device 1 according to an embodiment of the present invention. Figure 2 is a cross-sectional view of the antenna device 1. Figures 1 and 2 show mutually orthogonal X, Y, and Z axes. The antenna device 1 comprises an element surrounding section 10 and a power supply section 20.

[0014] The element enclosure 10 is made of a dielectric material. The element enclosure 10 is formed in a rectangular parallelepiped shape overall, with a rectangular prism-shaped recess D in the central part when viewed from the +Z axis direction. The recess D is defined by a bottom surface B and four sides S1 to S4. A rectangular radiating element R is placed in the central part on the bottom surface B. The radiating element R is an element that emits radio waves in the +Z axis direction when a high-frequency signal is supplied from the power supply unit 20. The sides S1 to S4 surround the radiating element R when viewed from the direction perpendicular to the bottom surface B (the +Z axis direction in Figures 1 and 2). Sides S1 and S2 are sides aligned with the YZ plane and are opposite to each other. Sides S3 and S4 are sides aligned with the XZ plane and are opposite to each other.

[0015] Furthermore, as shown in Figure 2, a ground layer G3 is arranged on the back surface b side of the bottom surface B of the element enclosure 10. The bottom surface B corresponds to the "first surface," and the back surface b corresponds to the "second surface." That is, in the antenna device 1, the radiating element R is arranged on the first surface side, while the ground layer G3 is arranged on the second surface side. Also, the ground layers G1 and G2 are embedded inside the element enclosure 10 on the +Z axis side of the back surface b. The ground layers G1 to G3 are arranged in the order of ground layer G1, ground layer G2, and ground layer G3 from the +Z axis side. Each of the ground layers G1 to G3 is a plate-shaped metal member that extends along the XY plane and has a through hole formed in the center of the XY plane for positioning the power supply section 20. In this embodiment, the metal material forming each of the ground layers G1 to G3 is copper, but other metal materials such as silver may be used. A portion of the element surrounding part 10, made of dielectric material, is positioned between the ground layers G1 to G3 and in each of the through-holes. Furthermore, a protrusion 23, also made of dielectric material, is provided on the side of the ground layer G3 in the -Z-axis direction. Each of the ground layers G1 to G3 is electrically connected to one another via via V extending along the Z-axis direction. Because the ground layers G1 to G3 and the radiating element R are positioned opposite each other, the ground of the antenna device 1 is strengthened, which is effective in improving the antenna characteristics. Antenna characteristics here refer to, for example, VSWR and radiation pattern.

[0016] As shown in FIG. 2, a part of the surface of the ground layer G3 is covered with a plating layer P1. In this embodiment, the metal material forming the plating layer P1 is Au, but it may be Ni, Pd, etc., or an alloy thereof. The portion of the surface of the ground layer G3 that is different from the portion covered with the plating layer P1 is covered with an insulating paste layer ps mainly composed of glass or the like.

[0017] Also, as shown in FIG. 2, a power supply via that functions as a power supply unit 20 is connected to the radiation element R. The power supply unit 20 supplies power to the radiation element R. One end 21 of the power supply unit 20 is connected to the radiation element R. As shown in FIG. 1, the power supply unit 20 is connected to the radiation element R at a position shifted along the direction (the X-axis direction in this embodiment) in which the side surfaces S1 and S2 face each other from the center O of the radiation element R when viewed from the side in the +Z-axis direction, and supplies power to the radiation element R.

[0018] The other end 22 of the power supply unit 20 is provided so as to protrude further in the -Z-axis direction from the surface of the protrusion 23. The surface of the end 22 is covered with a plating layer P2. The metal material forming the plating layer P2 is Au, but it may be Ni, Pd, etc., or an alloy thereof. Also, the tip of the end 22 protrudes in the direction in which the back surface b faces (the -Z-axis direction in this embodiment) from the ground layer G3. In this embodiment, the surface of the end 22 and the surface of the ground layer G3 are covered with a plating layer P2 and a plating layer P1, respectively. Therefore, in such a case, when the tip of the end 22 protrudes in the direction in which the back surface b faces from the ground layer G3, it means that the position on the surface of the plating layer P2 that is farthest from the back surface b is farther from the back surface b than the position on the surface of the plating layer P1 that is farthest from the back surface b. In this embodiment, the plating layer P1 is disposed on each of the ±Y-axis direction sides when viewed from the plating layer P2. In such a case, the position on the surface of the plating layer P1 that is farthest from the back surface b shall be the position on the surface of the plating layer P1 that is closest to the XY plane from the plating layer P2 and is farthest from the back surface b.

[0019] Also, the distance from the ground layer G3 to the tip of the end portion 22 is 10 μm or more and less than 40 μm. In other words, the length along the direction (the Z-axis direction in this embodiment) in which the back surface b faces, from the position on the surface of the plating layer P1 that is farthest from the back surface b to the position on the surface of the plating layer P2 that is farthest from the back surface b, is 10 μm or more and less than 40 μm.

[0020] FIG. 3 is an explanatory diagram conceptually showing the position of the end portion 22 on the back surface b. FIG. 3 shows the position of the end portion 22 and the position of the plating layer P1 when the back surface b is viewed from the -Z-axis direction, which is the opposite direction of the back surface b. In this embodiment, when viewed from the opposite direction of the back surface b, the end portion 22 is disposed within a region Ar (the region within the rectangle indicated by the broken line) that is located closer to the center of the back surface b. Specifically, the region Ar corresponds to a region that is a similar shape to an area that is 50% of the cross-sectional area of the outer shape of the antenna device 1. In this embodiment, the end portion 22 is disposed at the center of the back surface b. Further, as shown in FIG. 3, on the back surface b, in addition to the plating layer P1 described in FIG. 2, a plurality of plating layers P0 are arranged at intervals. These plating layers P0 are provided to connect to pads on the circuit board 2 described below.

[0021] Figure 4 is a cross-sectional view of the circuit board 2. The circuit board 2 is a substrate on which the antenna device 1 described in Figures 1 and 2 is mounted, as well as circuit components (not shown) that form a high-frequency circuit for processing the high-frequency signals transmitted and received by the antenna device 1. For the circuit board 2, a PCB substrate such as a glass epoxy substrate can be used. The side of the circuit board 2 on which the antenna device 1 is mounted (the side in the +Z axis direction in Figure 4) is called surface F. Viewed from the opposite direction of surface F (in the +Z axis direction in Figure 4), the feed point FP is located near the center of the area on surface F where the antenna device 1 is mounted. The feed point FP is a power source that supplies high-frequency signals to the feed section 20 when connected to the end 22 of the antenna device 1. The metal material forming the feed point FP is copper, similar to the ground layers G1 to G3, but it may be a different metal material. The surface of the feed point FP is covered with a plating layer P4. The metal material forming the plating layer P4 is Au, but it may also be Ni, Pd, or an alloy thereof.

[0022] As shown in Figure 4, in addition to the power supply point FP, an electrode layer E is arranged on the surface F. In this embodiment, the metal material forming the electrode layer E is copper, similar to the ground layers G1 to G3, but it may be other metal materials such as silver. Furthermore, a portion of the surface of the electrode layer E is covered with a plating layer P3. The metal material forming the plating layer P3 is Au, similar to the plating layer P1, but it may be Ni, Pd, or an alloy thereof. The portion of the surface of the electrode layer E that is not covered by the plating layer P3 is covered with a solder resist layer SR.

[0023] Of the circuit board 2, the feed point FP and the plating layer P4 constitute a pad with an NSMD (Non Solder Mask Defined) structure. Hereafter, the feed point FP and the plating layer P4 may be collectively referred to as pad N. Of the circuit board 2, the electrode layer E, the plating layer P3, and the solder resist layer SR constitute a pad with an SMD (Solder Mask Defined) structure. Hereafter, the electrode layer E, the plating layer P3, and the solder resist layer SR may be collectively referred to as pad S. As a circuit board for mounting an antenna device 1 in which both the feed point 20 (end 22) and the ground layer G3 are provided on the back surface b, pad N, which is electrically connected to the end 22 of the feed point 20, and pad S, which is electrically connected to the ground layer G3, are provided on the circuit board 2 at positions facing the feed point 20 (end 22) and the ground layer G3.

[0024] Figure 5 is an explanatory diagram showing circuit board 2 with bump bm mounted. Generally, pads connected to the power supply section, which is responsible for supplying power to the radiating element, tend to use NSMD structure pads from an impedance standpoint. On the other hand, the height of a bump mounted on an NSMD structure pad tends to be lower than the height of a bump mounted on an SMD structure pad. As a concrete example of this tendency, Figure 5 shows that when bump bm is mounted on pad N and pad S respectively, the height of bump bm mounted on pad N is lower than the height of bump bm mounted on pad S. Here, it is assumed that the diameter of bump bm before being mounted on pad N and the diameter of bump bm before being mounted on pad S are the same. In this embodiment, both the NSMD structure of pad N and the SMD structure of pad S include plating layers P4 and P3, which are UBM (Under Bump Metal) (see Figure 4). However, even when comparing an SMD structure pad without UBM and an NSMD structure pad without UBM, the height of the bump placed on the NSMD structure pad tends to be lower than the height of the bump placed on the SMD structure pad.

[0025] Figure 6 is an explanatory diagram showing the antenna device 1 mounted on the circuit board 2 via the bump bm. As described above, in the antenna device 1, the tip of the end portion 22 protrudes in the direction where the back surface b faces the ground layer G3 (in this embodiment, the -Z axis direction). Therefore, even if a bump bm with a diameter adjusted to connect the pad S and the plating layer P1 is placed on the pad N, the pad N and the end portion 22 can be connected via the bump bm.

[0026] According to the antenna device 1 of the embodiment described above, the radiating element R is surrounded by four side surfaces S1 to S4 that define the recessed portion D of the element surrounding portion 10, which is made of dielectric material, when viewed from the direction orthogonal to the bottom surface B (in this embodiment, the +Z axis direction). Therefore, the electromagnetic distribution of the side surfaces S1 to S4 made of dielectric material can be used to widen the radiation directivity of the radio waves radiated from the radiating element R.

[0027] Furthermore, according to the antenna device 1 of this embodiment, the tip of the end 22 of the power supply unit 20 that is connected to the pad N protrudes in a direction where the back surface b faces the ground layer G3. Therefore, even if a bump of the same diameter as the bump placed on the pad S connected to the ground layer G3 (a bump with a diameter adjusted to connect the pad S and the plating layer P1) is placed on the pad N on the circuit board 2 on which the antenna device 1 is mounted, the pad N and the power supply unit 20 (end 22) can be connected. In other words, since it is not necessary to place a bump with a larger diameter on the pad N than the bump placed on the pad S connected to the ground layer G3, the complexity of the mounting process on the circuit board 2 can be suppressed.

[0028] To address the tendency for bumps placed on NSMD pads to be lower than those placed on SMD pads, one could consider placing bumps with a larger diameter on pad N than those placed on pad S, or applying solder paste to pad N to bring its height closer to that of pad S. However, this measure, like placing bumps of different diameters, complicates the mounting process. In this respect as well, the antenna device 1 of the embodiment has an advantage because the tip of the end 22 protrudes in the direction of the back surface b rather than the ground layer G3, eliminating the need to apply solder paste and thus preventing the mounting process to the circuit board 2 from becoming complicated. In other words, the antenna device 1 of the embodiment prevents an increase in the amount of solder and work required for mounting to the circuit board 2. Therefore, it is also possible to prevent the deterioration of antenna characteristics caused by changes in impedance matching due to an increase in the amount of solder and work. In this context, antenna performance degradation refers to, for example, an increase in the VSWR value, which in turn leads to a decrease in transmission efficiency and a deterioration in reception sensitivity.

[0029] Furthermore, according to the antenna device 1 of the embodiment, the distance from the ground layer G3 to the tip of the end 22 is 10 μm or more and less than 40 μm. When there is a distance difference of this magnitude between the ground layer G3 and the tip of the end 22, when a bump of the same diameter as the bump placed on the pad S to connect to the ground layer G3 is placed on the pad N, the connection between the power supply unit 20 and the pad N can be ensured with high accuracy.

[0030] Furthermore, according to the antenna device 1 of this embodiment, as explained in Figure 3, when viewed from the opposite direction on the back surface b, the end portion 22 is located within region Ar on the back surface b. In this embodiment, the end portion 22 is located in the center of the back surface b. Therefore, impedance mismatch is less likely to occur at the end portion 22, and high-frequency signals can be supplied from the circuit board 2 to the power supply unit 20 while suppressing loss of high-frequency signals.

[0031] <Modified form of this embodiment> The present invention is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit, for example, the following modifications are also possible.

[0032] In the above embodiment, the element surrounding portion 10 may be formed by integrating the portion surrounding the recessed portion D with a plate-like portion including the bottom surface B and the back surface b, or they may be formed separately and then integrated by adhesive. Furthermore, although the element surrounding portion 10 was formed as a rectangular parallelepiped overall in the above embodiment, the overall shape may be any three-dimensional shape as long as it has a rectangular prism-shaped recessed portion D in the central part when viewed from the +Z axis side.

[0033] In the above embodiment, the radiating element R was rectangular in shape, but it may be any shape, such as a circle or a polygon.

[0034] In the above embodiment, plating layers P2 and P1 were formed on the surface of the end portion 22 and the surface of the ground layer G3, respectively, but this is not limited to this. Plating layer P2 does not need to be formed on the surface of the end portion 22, and plating layer P1 does not need to be formed on the surface of the ground layer G3. If plating layers P2 and P1 are not formed, the tip of the end portion 22 that protrudes in the direction facing the back surface b from the ground layer G3 is the position on the surface of the end portion 22 that is furthest from the back surface b. Also, if plating layers P2 and P1 are not formed, the position of the ground layer G3 that is compared with the tip of the end portion 22 is the position on the surface of the ground layer G3 that is furthest from the back surface b. Also, if plating layers P2 and P1 are not formed, the distance from the ground layer G3 to the tip of the end portion 22 is the length along the direction facing the back surface b from the position on the surface of the ground layer G3 that is furthest from the back surface b to the position on the surface of the end portion 22 that is furthest from the back surface b.

[0035] In the above embodiment, the end portion 22 was located in the center of the back surface b, but the end portion 22 may be located at any position on the back surface b. Of course, from the viewpoint of stably supplying high-frequency signals, it is preferable that the end portion 22 be located within region Ar on the back surface b.

[0036] The embodiments of this specification have been described above based on the embodiments and modifications described above. The embodiments described above are for the purpose of facilitating understanding of this specification and do not limit it. This specification may be modified and improved without departing from its spirit and the scope of the claims, and equivalents thereof are included in this specification. Furthermore, any technical features that are not described as essential in this specification may be deleted as appropriate. [Explanation of Symbols]

[0037] 1…Antenna device 2…Circuit board 10... Elements surrounding area 20... Power supply section 21…End 22...end 23...Protrusion Ar…Area B…Bottom surface D... recessed area E…electrode layer F… side FP…Power supply point G1~G3...Grand Layer O…center P0, P1, P2... Plating layers P3, P4... Plating layer R... Radiation S1,S2,S3,S4...side SR...Solder Resistance Layer V...Beer b…Back side ps...insulating paste layer

Claims

1. An antenna device, An element arrangement section comprising a first surface and a second surface which is the back surface of the first surface, wherein a radiating element is arranged on the side of the first surface and a ground layer is arranged on the side of the second surface, The device comprises a power supply unit having one end connected to the radiating element and the other end protruding from the second surface to supply power to the radiating element, An antenna device characterized in that the tip of the other end protrudes in a direction in which the second surface faces the ground layer.

2. The antenna device according to claim 1, An antenna device characterized in that the distance along the direction from the ground layer to the tip is 10 μm or more and less than 40 μm.

3. An antenna device according to claim 1 or claim 2, An antenna device characterized in that, when viewed from the opposite direction of the second surface, the other end is located in a region of the second surface that is closer to the center and is similar in shape to a region with an area of ​​50% of the cross-sectional area of ​​the outer shape of the antenna device.

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