Planar array antenna

Abstract

The present invention achieves a planar array antenna having increased flexural strength. Provided is a planar array antenna 110 in which a plurality of radiating elements are arranged along one direction on a dielectric substrate. The planar array antenna 110 comprises a common ground conductor plate 113 which is provided so as to be shared by the plurality of radiating elements. Planar antenna regions 110a, which respectively correspond to the radiating elements 111, have a common ground conductor plate 113 that is provided in parallel in the arrangement direction of the plurality of radiating elements 111 and a pair of ground conductor patterns 112a, 112b that are connected via a via conductor VI. A first dummy pattern DP1a, DP1b is provided between ground conductor patterns 112a, 112b which are adjacent to each other in the arrangement direction.

Description

Planar array antenna

[0001] The present invention relates to a planar array antenna.

[0002] For example, a planar array antenna capable of transmitting and receiving electromagnetic waves with high directivity used in wireless communication such as the fifth-generation mobile communication system (5G) is disclosed (for example, Patent Document 1).

[0003] International Publication No. 2020 / 158810

[0004] The planar array antenna described in Patent Document 1 is configured by arranging a plurality of planar antennas in one direction on a dielectric substrate. In order to prevent breakage when mounting such a planar array antenna in a housing of a mobile communication terminal such as a smartphone, it is required to increase the flexural strength of the antenna component.

[0005] The present disclosure has been made in view of the above, and an object thereof is to realize a planar array antenna with increased flexural strength.

[0006] The planar array antenna according to one aspect of the present disclosure is a planar array antenna having a plurality of radiating elements arranged side by side in one direction on a dielectric substrate and a common ground conductor plate provided in common to the plurality of radiating elements. In a planar antenna region corresponding to each of the radiating elements, a pair of ground conductor patterns provided in parallel with the arrangement direction of the plurality of radiating elements and connected to the common ground conductor plate via via conductors are provided, and a first dummy pattern is provided between the ground conductor patterns adjacent to each other in the arrangement direction.

[0007] According to the present disclosure, a planar array antenna with increased flexural strength can be realized.

[0008] Figure 1 is a conceptual diagram showing an example of the block configuration of a communication device using a planar array antenna according to the embodiment. Figure 2 is a perspective view showing an example of a planar array antenna according to the embodiment. Figure 3 is a diagram showing an example of a schematic cross-sectional structure of the planar antenna region. Figure 4 is a perspective view of the ground conductor pattern as seen from the normal direction of the dielectric substrate constituting the planar array antenna according to the embodiment. Figure 5 is a perspective view of the ground conductor pattern as seen from the normal direction of the dielectric substrate according to the first comparative example. Figure 6 is a schematic cross-sectional view along the ground conductor pattern of the dielectric substrate according to the first comparative example. Figure 7A is a schematic cross-sectional view along the alignment direction of the first dummy pattern according to the embodiment. Figure 7B is a schematic cross-sectional view along the alignment direction of the second dummy pattern according to the embodiment. Figure 8A is a schematic cross-sectional view along the alignment direction of the first dummy pattern according to the second comparative example. Figure 8B is a schematic cross-sectional view along the alignment direction of the second dummy pattern according to the second comparative example.

[0009] A planar array antenna according to an embodiment will be described in detail below with reference to the drawings. However, this embodiment is not limited to the present disclosure.

[0010] Figure 1 is a conceptual diagram showing an example of a block configuration of a communication device using a planar array antenna according to an embodiment. The communication device 1 is, for example, a mobile terminal such as a mobile phone, smartphone, or tablet, or a personal computer equipped with communication functions.

[0011] As shown in Figure 1, the communication device 1 comprises an antenna module 100 and a BBIC (Base Band Integrated Circuit) 200 that performs baseband signal processing. The BBIC 200 is mounted on the main board 20 of the communication device 1.

[0012] The antenna module 100 comprises a planar array antenna 110 according to the embodiment, a high-frequency circuit including an RFIC (Radio Frequency Integrated Circuit) 121 for processing high-frequency signals of transmitted and received signals, and a power supply circuit including a PMIC (Power Management Integrated Circuit) 122 for supplying power supply voltage to the RFIC 121, all packaged on the same substrate as a System in Package (SiP) 120.

[0013] In this disclosure, the antenna module 100 is connected to the main board 20 of the communication device 1 via a connection portion 150. Specifically, the antenna module 100 and the main board 20 of the communication device 1 are electrically connected, for example, via a high-frequency multi-pole connector. Alternatively, the antenna module 100 and the main board 20 of the communication device 1 may be electrically connected using, for example, an anisotropic conductive film (ACF).

[0014] Figure 2 is a perspective view showing an example of a planar array antenna according to an embodiment. In this disclosure, the planar array antenna 110 has a plurality of radiating elements 111 arranged in one direction (the Y direction in the example shown in Figure 2), and a common ground conductor plate 113 provided in common to the plurality of radiating elements 111. In Figure 2, the boundary lines of the planar antenna regions 110a corresponding to each radiating element 111 are shown by dashed lines. Here, an example is shown in which six planar antenna regions 110a are arranged in the Y direction, but the number of planar antenna regions 110a is not limited to this.

[0015] Although not shown in Figure 2, the SiP 120 is mounted, for example, on the back surface of the plane array antenna 110 where multiple radiating elements 111 are provided. Examples of mounting methods for the SiP 120 to the plane array antenna 110 include soldering, but other methods include fusion or compression bonding by heating or pressurizing the joint, or bonding using thermosetting resin or adhesive. Furthermore, ultrasonic vibration may be used to heat or pressurize the joint.

[0016] Examples of dielectric substrates constituting the planar array antenna 110 include low-temperature co-fired ceramic (LTCC) multilayer substrates, multilayer resin substrates formed by laminating multiple resin layers made of epoxy, polyimide, and other resins, multilayer resin substrates formed by laminating multiple resin layers made of liquid crystal polymer (LCP) having a lower dielectric constant, multilayer resin substrates formed by laminating multiple resin layers made of fluororesin, and ceramic multilayer substrates (excluding low-temperature fired ceramic multilayer substrates).

[0017] Figure 3 shows an example of a schematic cross-sectional structure of a planar antenna region. Figure 3 illustrates the XZ planar cross-sectional view of the planar antenna region 110a.

[0018] The radiating element 111 is formed from a square-shaped conductive metal material. The common ground conductor plate 113 is formed from the same metal material or alloy as the radiating element 111. More specifically, the radiating element 111 and the common ground conductor plate 113 are formed from metal materials such as aluminum (Al), copper (Cu), gold (Au), silver (Ag), or alloys containing at least one of these materials. The shape of the radiating element 111 may be, for example, a round shape, a triangular shape, a hexagonal shape, or a special shape resulting from a combination thereof.

[0019] In this disclosure, each planar antenna region 110a is provided with a pair of ground conductor patterns 112a and 112b connected to a common ground conductor plate 113 via a via conductor VI in the inner layer of the dielectric substrate constituting the planar array antenna 110. The ground conductor patterns 112a and 112b adjust the distribution of electromagnetic waves radiated from the radiating element 111. In the example shown in Figure 3, a pair of ground conductor patterns 112a and 112b are provided in multiple layers of the inner layer of the dielectric substrate, and each is connected via a via conductor VI. This disclosure is not limited by the number of layers on which the ground conductor patterns 112a and 112b are provided.

[0020] The radiating elements 111 may be provided in multiples for each planar antenna region 110a, corresponding to, for example, high-band (e.g., 39 GHz band) and low-band (e.g., 28 GHz band) radio waves, respectively. In this case, the multiple radiating elements 111 may be arranged coaxially on top of each other when viewed in the normal direction (Z direction) of the dielectric substrate, or they may be arranged side by side on the surface of the dielectric substrate. The present disclosure is not limited by the configuration of the radiating elements 111.

[0021] Figure 4 is a perspective view of the ground conductor pattern as seen from the normal direction (Z direction) of the dielectric substrate constituting the planar array antenna according to the embodiment. The pair of ground conductor patterns 112a and 112b are each provided parallel to the arrangement direction of the radiating elements 111. In this disclosure, the arrangement direction of the radiating elements 111 is defined as the direction in which the area centers of the plurality of radiating elements 111 are aligned (here, the Y direction) when viewed in the normal direction (Z direction) of the dielectric substrate constituting the planar array antenna 110.

[0022] In this disclosure, first dummy patterns DP1a and DP1b are provided between adjacent ground conductor patterns 112a and 112b in the arrangement direction (Y direction) of a plurality of radiating elements 111.

[0023] The first dummy patterns DP1a and DP1b are provided on at least one of the multiple layers on which the ground conductor patterns 112a and 112b are provided. The first dummy patterns DP1a and DP1b include a plurality of first subdummy patterns SDP1 arranged in the direction of the arrangement of the radiating elements 111 (Y direction).

[0024] Specifically, the example shown in Figure 4 illustrates a configuration in which two first subdummy patterns SDP1 are provided in the alignment direction (Y direction) of the radiating element 111. In this case, the length of the two first subdummy patterns SDP1 in the alignment direction (Y direction) can be set based on the wavelength λ of the carrier wave radiated from the radiating element 111, for example, to about 0.1λ or less in wavelength within the dielectric. In the example shown in Figure 4, considering the flexural strength of the antenna module and the influence on the antenna characteristics due to the electrical length of the first subdummy patterns SDP1, the length of each of the multiple first subdummy patterns SDP1 provided in the same layer in the alignment direction (Y direction) is set to be equal, but the invention is not limited to this.

[0025] Furthermore, in this disclosure, a second dummy pattern DP2 is provided on the boundary line of adjacent planar antenna regions 110a. The second dummy pattern DP2 is provided on at least one of the multiple layers on which the ground conductor patterns 112a and 112b are provided.

[0026] The second dummy pattern DP2 includes a plurality of second subdummy patterns SDP2 arranged on the boundary lines of adjacent planar antenna regions 110a.

[0027] Specifically, the example shown in Figure 4 illustrates a configuration in which five second subdummy patterns SDP2 are provided on the boundary line of adjacent planar antenna regions 110a. In this case, the length of the second subdummy patterns SDP2 in the direction of alignment (X direction) can be set based on the wavelength λ of the carrier wave radiated from the radiating element 111, for example, about 0.1λ or less in wavelength within the dielectric, for example, 0.08λ or less. In the example shown in Figure 4, considering the flexural strength of the antenna module and the influence on antenna characteristics due to the electrical length of the second subdummy patterns SDP2, the example illustrates a case in which the lengths of each of the multiple second subdummy patterns SDP2 provided in the same layer are configured to be equal, but the example is not limited to this.

[0028] Figure 5 is a perspective view of the ground conductor pattern of the dielectric substrate according to the first comparative example, viewed from the normal direction. Figure 6 is a schematic cross-sectional view of the dielectric substrate according to the first comparative example along the ground conductor pattern. In the dielectric substrate according to the first comparative example shown in Figures 5 and 6, mechanical loads are easily applied near the boundary lines of adjacent planar antenna regions indicated by dashed lines. For example, in the process of mounting an antenna module into the housing of a communication device, there is a high possibility of fracture due to physical stress applied in the normal direction (Z direction) of the dielectric substrate by the pressing of the antenna module.

[0029] Figure 7A is a schematic cross-sectional view along the direction of arrangement (Y direction) of the first dummy pattern according to the embodiment. Figure 7B is a schematic cross-sectional view along the direction of arrangement (X direction) of the second dummy pattern according to the embodiment. Figure 7B illustrates a schematic cross-section along the boundary line of adjacent planar antenna regions 110a.

[0030] In the planar array antenna 110 according to this embodiment, as shown in Figure 7A, first dummy patterns DP1a and DP1b are provided between adjacent ground conductor patterns 112a and 112b.

[0031] Furthermore, Figure 7A illustrates an embodiment in which first dummy patterns DP1a and DP1b are provided on multiple layers on which ground conductor patterns 112a and 112b are provided. The first sub-dummy patterns SDP1 provided on multiple layers each overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (Y direction). Therefore, the first dummy patterns DP1a and DP1b provided on any one layer among the multiple layers on which ground conductor patterns 112a and 112b are provided overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (Y direction) with the first dummy patterns DP1a and DP1b provided on other layers. In other words, the gaps formed between the first dummy patterns DP1a and DP1b provided on the same layer of the dielectric substrate overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (Y direction) with any one layer and other layers.

[0032] Furthermore, in the planar array antenna 110 according to this embodiment, as shown in Figure 7B, a second dummy pattern DP2 is provided on the boundary line between adjacent planar antenna regions 110a.

[0033] Furthermore, Figure 7B illustrates an embodiment in which a second subdummy pattern SDP2 is provided on multiple layers on which ground conductor patterns 112a and 112b are provided. The second subdummy patterns SDP2 provided on multiple layers overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (X direction). Therefore, the second dummy patterns DP2a and DP2b provided on any one layer among the multiple layers on which ground conductor patterns 112a and 112b are provided overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (X direction) with the second dummy patterns DP2a and DP2b provided on other layers. In other words, the gaps formed between the second dummy patterns DP2a and DP2b provided on the same layer of the dielectric substrate overlap in the direction normal to the dielectric substrate (Z direction) and have equal lengths in the alignment direction (X direction) with any one layer and other layers.

[0034] This makes it possible to increase the flexural strength of the dielectric substrate constituting the planar array antenna 110, and for example, in the process of mounting the antenna module inside the housing of a communication device, it is possible to suppress the occurrence of fracture due to physical stress applied in the direction normal to the dielectric substrate.

[0035] Figure 8A is a schematic cross-sectional view of the first dummy pattern according to the second comparative example, along the direction of arrangement (Y direction). Figure 8B is a schematic cross-sectional view of the second dummy pattern according to the second comparative example, along the direction of arrangement (X direction). As shown in Figure 8A, for example, if multiple first subdummy patterns SDP1 are offset from layer to layer, coupling may occur in the first subdummy patterns SDP1 of each layer, potentially degrading the antenna characteristics. Alternatively, as shown in Figure 8B, for example, if multiple second subdummy patterns SDP2 are offset from layer to layer, coupling may occur in the second subdummy patterns SDP2 of each layer, potentially degrading the antenna characteristics.

[0036] In the planar array antenna 110 according to this embodiment, as shown in Figures 7A and 7B, a plurality of first subdummy patterns SDP1 and a plurality of second subdummy patterns SDP2 are arranged to overlap in the direction normal to the dielectric substrate (Z direction). This makes it possible to increase the flexural strength of the dielectric substrate constituting the planar array antenna 110 while suppressing the deterioration of antenna characteristics caused by the coupling of the first subdummy patterns SDP1 and the second subdummy patterns SDP2. For example, in the process of mounting an antenna module inside the housing of a communication device, it is possible to suppress the occurrence of fracture due to physical stress applied in the direction normal to the dielectric substrate.

[0037] The embodiments described above are provided to facilitate understanding of this disclosure and are not intended to limit the invention. This disclosure may be modified or improved without departing from its spirit, and equivalents thereof are included.

[0038] 1 Communication device 20 Main board 100 Antenna module 110 Planar array antenna 110a Planar antenna area 111 Radiating element 112a, 112b Ground conductor pattern 113 Common ground conductor plate 120 SiP 121 RFIC 122 PMIC 150 Connection part 200 BBIC DP1a, DP1b First dummy pattern DP2 Second dummy pattern SDP1 First subdummy pattern SDP2 Second subdummy pattern VI Via conductor

Claims

1. A planar array antenna having a plurality of radiating elements arranged in one direction on a dielectric substrate, and a common ground conductor plate provided in common to the plurality of radiating elements, wherein in the planar antenna region corresponding to each of the radiating elements, there is a pair of ground conductor patterns provided parallel to the arrangement direction of the plurality of radiating elements and connected to the common ground conductor plate via via conductors, and a first dummy pattern is provided between the ground conductor patterns that are adjacent to each other in the arrangement direction.

2. A planar array antenna according to claim 1, wherein the first dummy pattern includes a plurality of first subdummy patterns arranged in the direction of the array.

3. A planar array antenna according to claim 2, wherein the plurality of first subdummy patterns each have equal lengths in the direction of alignment.

4. A planar array antenna according to claim 1, wherein the ground conductor pattern is provided in a plurality of inner layers of the dielectric substrate, and the first dummy pattern is provided in at least one of the plurality of layers on which the ground conductor pattern is provided.

5. A planar array antenna according to claim 1, wherein the ground conductor pattern is provided in a plurality of inner layers of the dielectric substrate, the first dummy pattern is provided in two or more layers of the plurality of layers on which the ground conductor pattern is provided, and the first dummy pattern provided in one of the plurality of layers overlaps with the first dummy patterns provided in the other layers in the direction normal to the dielectric substrate.

6. A planar array antenna according to claim 5, wherein a first dummy pattern provided in one layer includes a plurality of first subdummy patterns arranged in the direction of the array, a first dummy pattern provided in another layer includes a plurality of first subdummy patterns arranged in the direction of the array, and the first subdummy pattern provided in one layer overlaps the first subdummy patterns provided in the other layer in the direction normal to the dielectric substrate, and has the same length in the direction of alignment as the first subdummy patterns provided in the other layer.

7. A planar array antenna according to claim 1 or 2, wherein a second dummy pattern is provided on the boundary line between adjacent planar antenna regions.

8. A planar array antenna according to claim 7, wherein the second dummy pattern includes a plurality of second subdummy patterns aligned on the boundary lines of adjacent planar antenna regions.

9. A planar array antenna according to claim 8, wherein the plurality of second subdummy patterns each have equal lengths in the direction of alignment.

10. A planar array antenna according to claim 4, wherein a second dummy pattern is provided on the boundary line between adjacent planar antenna regions, and the second dummy pattern is provided on at least one of the plurality of layers on which the ground conductor pattern is provided.

11. A planar array antenna according to claim 5 or 6, wherein a second dummy pattern is provided on the boundary line between adjacent planar antenna regions, the second dummy pattern is provided on two or more layers of a plurality of layers on which the ground conductor pattern is provided, and the second dummy pattern provided on one layer overlaps with the second dummy pattern provided on another layer in the direction normal to the dielectric substrate.

12. A planar array antenna according to claim 11, wherein a second dummy pattern provided in one layer includes a plurality of second subdummy patterns aligned on the boundary line of adjacent planar antenna regions, a second dummy pattern provided in another layer includes a plurality of second subdummy patterns aligned on the boundary line of adjacent planar antenna regions, and a second subdummy pattern provided in one layer overlaps with a second subdummy pattern provided in another layer in the direction normal to the dielectric substrate, and has the same length in the alignment direction as the second subdummy pattern provided in another layer.

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