Antenna device and wireless communication device

Abstract

The present invention easily adjusts gain even when using an antenna module. This antenna device comprises: an antenna module that includes a patch antenna; a parasitic element that is disposed in the direction in which the patch antenna emits radio waves; wiring connected to the parasitic element; and a switching unit provided at a position that divides the wiring into a first portion the length of which corresponds to the wavelength of the radio waves from the parasitic element, and a second portion excluding the first portion, the switching part connecting and disconnecting the first portion and the second portion.

Description

[Technical Field]

[0001] The present invention relates to an antenna device and a wireless communication device. [Background technology]

[0002] In antenna devices, various efforts have been made to improve gain, reduce size, and the like (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-244961 [Patent Document 2] Japanese Patent Application Laid-Open No. 2002-135040 Summary of the Invention [Problem to be solved by the invention]

[0004] Radio wave laws and other regulations may restrict the gain of antennas when they come close to the human body. Therefore, it is possible to reduce the gain by modifying the antenna circuit. However, when using an antenna module in which the antenna and its associated circuits are modularized, it is difficult to modify the circuitry within the antenna module. Therefore, when using an antenna module, it is difficult to reduce the gain to the desired level.

[0005] An object of one aspect of the disclosed technique is to provide an antenna device and a wireless communication device that can easily adjust the gain even when an antenna module is employed. [Means for solving the problem]

[0006] One aspect of the disclosed technology is exemplified by the following antenna device: The antenna device includes an antenna module including a patch antenna, a parasitic element arranged in a direction in which the patch antenna emits radio waves, wiring connected to the parasitic element, and a switching unit provided at a position that divides the wiring from the parasitic element into a first portion having a length corresponding to the wavelength of the radio waves and a second portion excluding the first portion, and that connects and disconnects the first portion and the second portion. [Effects of the Invention]

[0007] According to the disclosed technology, even when an antenna module is employed, the gain can be easily adjusted. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of an antenna device according to an embodiment. [Figure 2] FIG. 2 is a side view of the antenna device according to the embodiment. [Figure 3] FIG. 3 is a layout diagram of components mounted on the bottom surface of the antenna device according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating an example of a hardware configuration of the control device. [Figure 5] FIG. 5 is a first diagram schematically illustrating the relationship between the length of the wiring connected to the switch and the gain of the antenna. [Figure 6] FIG. 6 is a second diagram schematically illustrating the relationship between the length of the wiring connected to the switch and the gain of the antenna. [Figure 7] FIG. 7 is a first diagram illustrating a state in which a switch is provided midway along a wire connected to a stacked patch. [Figure 8] FIG. 8 is a second diagram illustrating a state in which a switch is provided midway along the wiring connected to the stacked patch. [Figure 9] FIG. 9 is a first diagram illustrating combinations of the positions of switches provided on the wiring and the termination conditions of the wiring. [Figure 10]FIG. 10 is a second diagram illustrating combinations of the positions of switches provided on the wiring and the termination conditions of the wiring. [Figure 11] FIG. 11 is a third diagram illustrating combinations of the positions of switches provided on the wiring and the termination conditions of the wiring. [Figure 12] FIG. 12 is a fourth diagram illustrating combinations of the positions of switches provided on the wiring and the termination conditions of the wiring. [Figure 13] FIG. 13 is a diagram showing an example of a configuration in which two stacked patches are connected by a wire. [Figure 14] FIG. 14 is a diagram showing another example of a configuration in which two stacked patches are connected by a wire. [Figure 15] FIG. 15 is a diagram showing an example of a configuration in which three stacked patches are connected by wiring. [Figure 16] FIG. 16 is a plan view illustrating the configuration employed in the simulation. [Figure 17] FIG. 17 is a diagram illustrating the results of the first simulation. [Figure 18] FIG. 18 is a diagram illustrating a state in which no stacked patch is provided in the second simulation. [Figure 19] FIG. 19 is a diagram illustrating a radiation pattern when no stacked patch is provided. [Figure 20] FIG. 20 is a diagram illustrating a state in which stacked patches are provided in the second simulation. [Figure 21] FIG. 21 is a diagram illustrating a state in which adjacent stacked patches are connected by wiring in the second simulation. [Figure 22] FIG. 22 is a diagram illustrating a state in which two stacked patches are connected by a wire in the third simulation. [Figure 23] FIG. 23 is a diagram illustrating a state in which three stacked patches are connected by wiring in the third simulation. [Figure 24]FIG. 24 is a diagram schematically showing the relationship between the wiring length and the current distribution in the fourth simulation. [Figure 25] FIG. 25 is a diagram summarizing the results of the fourth simulation. [Figure 26] FIG. 26 is a diagram schematically showing the current distribution in the fifth simulation. [Figure 27] FIG. 27 is a diagram summarizing the results of the fifth simulation. [Figure 28] FIG. 28 is a diagram schematically showing the relationship between the wiring length and the current distribution in the sixth simulation. [Figure 29] FIG. 29 is a diagram summarizing the results of the sixth simulation. [Figure 30] FIG. 30 is a diagram illustrating a case in which two pairs of a patch antenna and a stacked patch are arranged side by side and the respective stacked patches are connected by wiring in the seventh simulation. [Figure 31] FIG. 31 is a diagram illustrating a case in which four pairs of a patch antenna and a stacked patch are arranged side by side and adjacent stacked patches are connected by wiring in the seventh simulation. [Figure 32] FIG. 32 is a diagram illustrating an example of a smartphone according to the first modification. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Embodiment> The configurations of the embodiments described below are examples, and the disclosed technology is not limited to the configurations of the embodiments. An antenna device according to the embodiments has, for example, the following configuration: The antenna device according to the present embodiment includes an antenna module including a patch antenna, a parasitic element arranged in a direction in which the patch antenna radiates radio waves, wiring connected to the parasitic element, and a switching unit provided at a position that divides the wiring into a first portion having a length corresponding to the wavelength of the radio waves from the parasitic element and a second portion excluding the first portion, and that connects and disconnects the first portion and the second portion.

[0010] In this embodiment, a parasitic element is arranged in the direction in which the patch antenna radiates radio waves, and wiring is connected to this parasitic element. By providing the parasitic element and wiring in this manner, the patch antenna and wiring can be easily installed even when the patch antenna is modularized. The gain of the antenna device is adjusted by connecting or disconnecting the first and second portions using a switching unit provided in the first portion, whose length is determined according to the wavelength of the radio waves radiated by the patch antenna. Therefore, with this antenna device, gain adjustment is easy even when an antenna module is used.

[0011] (Configuration of antenna device 1) Hereinafter, the embodiments of the antenna device will be further described with reference to the drawings. Figs. 1, 2, and 3 are diagrams showing an example of an antenna device 1 according to an embodiment. Fig. 1 is a perspective view of the antenna device 1 according to the embodiment. Fig. 2 is a side view of the antenna device 1 according to the embodiment. Fig. 3 is a layout diagram of components mounted on the bottom surface of the antenna device 1 according to the embodiment. The antenna device 1 is a millimeter-wave antenna device including a millimeter-wave antenna module 10 and a stacked patch module 20. Hereinafter, in this specification, the depth direction of the antenna device 1 is referred to as the X direction, the width direction of the antenna device 1 as the Y direction, and the height direction of the antenna device 1 as the Z direction.

[0012] Referring to FIG. 1, the millimeter-wave antenna module 10 has four patch antennas 11 arranged in a row. The patch antennas 11 are plate-shaped antennas made of metal. The patch antennas 11 are exposed on the outer surface of the millimeter-wave antenna module 10. For example, the patch antennas 11 are formed in a rectangular shape when viewed from the front (when viewed in the X direction). The patch antennas 11 radiate radio waves in the X direction, for example. The spacing between adjacent patch antennas 11 is, for example, λ / 2, where λ is the wavelength of the patch antenna 11. When distinguishing between the four patch antennas 11, the patch antennas 11 are also referred to as patch antenna 11a, patch antenna 11b, patch antenna 11c, and patch antenna 11d.

[0013] The stacked patch module 20 includes stacked patches 21, switches 22, wiring 23, and a flexible substrate 24. As illustrated in FIG. 2, the flexible substrate 24 is bent into an L-shape when viewed in the Y direction, forming a front plate portion 24a and a bottom plate portion 24b. The front plate portion 24a is disposed in front of the surface of the millimeter-wave antenna module 10 on which the patch antenna 11 is disposed. Four stacked patches 21 are disposed in a row on the front plate portion 24a. The stacked patches 21 are elements that are not fed with power (parasitic elements). When distinguishing between the four stacked patches 21, the stacked patches 21 are also referred to as stacked patch 21a, stacked patch 21b, stacked patch 21c, and stacked patch 21d.

[0014] When viewed in the X direction, stacked patch 21a is arranged at a position overlapping with patch antenna 11a, stacked patch 21b is arranged at a position overlapping with patch antenna 11b, stacked patch 21c is arranged at a position overlapping with patch antenna 11c, and stacked patch 21d is arranged at a position overlapping with patch antenna 11d. That is, the interval between adjacent stacked patches 21 is λ / 2, similar to that of patch antenna 11.

[0015] 1 and 3, each stacked patch 21 is connected to a wiring 23 extending from the stacked patch 21 to a bottom plate portion 24b of the flexible substrate 24. When distinguishing between the four wirings 23, the wirings 23 are also referred to as wiring 23a, wiring 23b, wiring 23c, and wiring 23d. Wiring 23a is connected to stacked patch 21a, wiring 23b is connected to stacked patch 21b, wiring 23c is connected to stacked patch 21c, and wiring 23d is connected to stacked patch 21d.

[0016] 2 and 3, the bottom plate portion 24b is attached to the bottom surface of the millimeter-wave antenna module 10. The bottom plate portion 24b is adhered to the bottom surface of the millimeter-wave antenna module 10 by, for example, double-sided tape. By attaching the bottom plate portion 24b to the bottom surface of the millimeter-wave antenna module 10, the distance between the patch antenna 11 and the stacked patch 21 is set to a constant stack-patch distance D1.

[0017] Three switches 22 are arranged on the bottom panel portion 24b, and wiring 23 is connected to the switches 22. The switches 22 are switched on / off in response to an input control signal. The control signal is input from, for example, the control device 100. When distinguishing between the three switches 22, the switches 22 are also referred to as switch 22a, switch 22b, and switch 22c, respectively.

[0018] A switch 22a is connected between the wiring 23a and the wiring 23b on the bottom plate portion 24b. A switch 22b is connected between the wiring 23b and the wiring 23c on the bottom plate portion 24b. A switch 22c is connected between the wiring 23c and the wiring 23d on the bottom plate portion 24b. By switching the switch 22 on and off, adjacent stacked patches 21 are electrically connected or disconnected. For example, when the switch 22a is turned on, the stacked patch 21a and the stacked patch 21b are electrically connected. The switch 22 is an example of a "switching portion."

[0019] (Hardware configuration of the control device 100) 4 is a diagram showing an example of the hardware configuration of the control device 100. The control device 100 includes a central processing unit (CPU) 101, a main memory unit 102, an auxiliary memory unit 103, a communication unit 104, and a sensor 105. The CPU 101, the main memory unit 102, the auxiliary memory unit 103, the communication unit 104, and the sensor 105 are interconnected by a connection bus B1.

[0020] The CPU 101 is also referred to as a microprocessor unit (MPU) or a processor. At least some of the processing performed by the CPU 101 may be performed by a dedicated processor other than the CPU 101, such as a digital signal processor (DSP), a graphics processing unit (GPU), a numerical calculation processor, a vector processor, or an image processing processor. The CPU 101 may also be a combination of a processor and an integrated circuit. This combination is called, for example, a microcontroller unit (MCU), a system-on-a-chip (SoC), a system LSI, or a chipset. In the control device 100, the CPU 101 loads a program stored in the auxiliary storage unit 103 into a working area in the main storage unit 102 and transmits control signals via the communication unit 104 through the execution of the program. The main storage unit 102 and the auxiliary storage unit 103 are recording media readable by the control device 100.

[0021] The main storage unit 102 is exemplified as a storage unit that is directly accessed by the CPU 101. The main storage unit 102 includes a random access memory (RAM) and a read only memory (ROM).

[0022] The auxiliary storage unit 103 stores various programs and various data on a readable and writable recording medium. The auxiliary storage unit 103 is also called an external storage device. The auxiliary storage unit 103 stores an operating system (OS), various programs, various tables, etc.

[0023] The auxiliary storage unit 103 is, for example, an erasable programmable ROM (EPROM), a solid state drive (SSD), a hard disk drive (HDD), or the like.

[0024] The communication unit 104 is, for example, an interface with the switch 22. The CPU 101 transmits a control signal to the switch 22 via the communication unit 104.

[0025] The sensor 105 acquires information about the surroundings of the antenna device 1. Examples of the sensor 105 include a proximity sensor and a Global Positioning System (GPS) sensor. Examples of the proximity sensor include a capacitance proximity sensor and an optical proximity sensor.

[0026] (Gain change due to the length of wire 23) 5 and 6 are diagrams schematically illustrating the relationship between the length of the wiring 23 connected to the switch 22 and the gain of the antenna. In FIGS. 5 and 6, the gain is illustrated when the lengths of the wiring 23 are λ / 4, λ / 2, 3λ / 4, and λ. In FIG. 5, the gain also illustrates a case where the wiring 23 is not connected to the stacked patch 21 (when the length of the wiring 23 is 0). In FIGS. 5 and 6, the "normal" gain illustrates the gain when the wiring 23 is not connected to the stacked patch 21.

[0027] 5 illustrates an example of a change in gain when the end of wiring 23 is open. When the end of wiring 23 is open, a gain equivalent to "normal" can be obtained when the length to the open end T1 of wiring 23 is 0, λ / 2, or λ. On the other hand, when the end of wiring 23 is open, the gain is suppressed more than "normal" when the length to the open end T1 of wiring 23 is λ / 4 or 3λ / 4.

[0028] 6 illustrates an example of a change in gain when the end of the wiring 23 is shorted (connected to ground). When the end of the wiring 23 is shorted, a gain equivalent to "normal" can be obtained when the length of the wiring 23 to the ground end T2 is λ / 4 or 3λ / 4. On the other hand, when the end of the wiring 23 is shorted, the gain is suppressed compared to "normal" when the length of the wiring 23 to the ground end T2 is λ / 2 or λ. As described with reference to FIGS. 5 and 6, the gain can be set to "normal" or suppressed below "normal" depending on the length and termination state of the wiring 23.

[0029] 7 and 8 are diagrams illustrating a state in which a switch 22 is provided midway along the wiring 23 connected to the stacked patch 21. FIG. 7 illustrates a case in which the length of the wiring 23 from the stacked patch 21 to the open end T1 is set to 3λ / 4. In the example of FIG. 7, the switch 22 is provided at a position such that the length of the wiring 23 connected to the stacked patch 21 becomes λ / 2 when the switch 22 is turned off. When the switch 22 is turned off, the portion of the wiring 23 from the switch 22 to the open end T1 is disconnected from the stacked patch 21. In other words, the length of the wiring 23 connected to the stacked patch 21 can be changed by turning the switch 22 on and off. By providing the switch 22 in this manner, a "normal" gain can be achieved by turning the switch 22 off, and a gain that is more suppressed than the "normal" gain can be achieved by turning the switch 22 on. The portion of the wiring 23 closer to the stacked patch 21 than the switch 22 is an example of a "first portion." The portion of the wiring 23 closer to the open end T1 than the switch 22 is an example of a "second portion."

[0030] 8 illustrates a case where the length of the wiring 23 from the stacked patch 21 to the open end T1 is set to λ. In the example of FIG. 8, the switch 22 is provided at a position where the length of the wiring 23 connected to the stacked patch 21 is 3λ / 4 when the switch 22 is turned off. By providing the switch 22 in this manner, a gain that is suppressed more than "normal" can be obtained by turning the switch 22 off, and a gain of "normal" can be obtained by turning the switch 22 on. As described with reference to FIGS. 7 and 8, the gain of the antenna can be adjusted by switching the length of the wiring 23 connected to the stacked patch 21 by turning the switch 22 on and off.

[0031] 5 to 8, the gain of the antenna can be adjusted by the length of the wiring 23 connected to the stacked patch 21 and the termination conditions of the wiring 23. A switch 22 can be used to change the length of the wiring 23.

[0032] 9 to 12 are diagrams illustrating combinations of the position of the switch 22 provided on the wiring 23 and the termination conditions of the wiring 23. Examples of the termination conditions include an open end of the wiring 23 and a grounded end of the wiring 23. Note that "x" and "y" in FIGS. 9 to 12 are any integers equal to or greater than 0. The same applies to "x" and "y" hereinafter in this specification.

[0033] 9 illustrates a state in which the end of the wiring 23 is open. Also, in FIG. 9, the length of the wiring 23 from the stacked patch 21 to the switch 22 is an even multiple of λ / 4, and the switch 22 is provided at a position where the length from the switch 22 to the open end T1 is an odd multiple of λ / 4. With these termination conditions and the arrangement of the switch 22, turning the switch 22 off results in a "normal" gain, and turning the switch 22 on results in a gain that is more suppressed than the "normal" gain.

[0034] 10 illustrates a state in which the termination of the wiring 23 is grounded. Also, in FIG. 10, the length of the wiring 23 from the stacked patch 21 to the switch 22 is an even multiple of λ / 4, and the switch 22 is provided at a position where the length from the switch 22 to the ground end T2 is an even multiple of λ / 4. With these termination conditions and the arrangement of the switch 22, turning the switch 22 off results in a "normal" gain, and turning the switch 22 on results in a gain that is more suppressed than the "normal" gain.

[0035] 11 illustrates a state in which the end of the wiring 23 is open. Also, in FIG. 11, the length of the wiring 23 from the stacked patch 21 to the switch 22 is an odd multiple of λ / 4, and the switch 22 is provided at a position where the length from the switch 22 to the open end T1 is an even multiple of λ / 4. With these termination conditions and the arrangement of the switch 22, turning the switch 22 off results in a gain that is more suppressed than "normal," and turning the switch 22 on results in a "normal" gain.

[0036] 12 illustrates a state in which the termination of the wiring 23 is grounded. Also, in FIG. 12, the length of the wiring 23 from the stacked patch 21 to the switch 22 is an odd multiple of λ / 4, and the switch 22 is provided at a position where the length from the switch 22 to the ground end T2 is an odd multiple of λ / 4. Under these termination conditions and placement of the switch 22, turning the switch 22 off results in a gain that is more suppressed than "normal," and turning the switch 22 on results in a "normal" gain. As described with reference to FIGS. 9 to 12, placing the switch 22 allows the length of the wiring 23 that is actually connected to the stacked patch 21 to be changed, thereby adjusting the antenna gain.

[0037] (About the connection of Stacked Patch 21) By making the termination conditions of the plurality of stacked patches 21 uniform, the plurality of stacked patches 21 can be connected by wiring 23. FIG. 13 is a diagram showing an example of a configuration in which two stacked patches 21 are connected by wiring 23. FIG. 13 illustrates a case in which two stacked patches 21 are connected by sharing an open end T1, and the length of the wiring 23 from the stacked patch 21 to the switch 22 is λ / 2, and the length of the wiring 23 from the switch 22 to the open end is λ / 4. With this arrangement, turning off the two switches 22 results in a "normal" gain, and turning on the two switches 22 results in a gain that is suppressed more than "normal."

[0038] FIG. 14 is a diagram showing another example of a configuration in which two stacked patches 21 are connected by a wiring 23. In FIG. 13, a switch 22 is provided for each of the two stacked patches 21, but in FIG. 14, one switch 22 is shared by the two stacked patches 21. In FIG. 14, due to the current distribution of the current flowing through the wiring 23, the open end T1 is located at a position λ / 4 from the stacked patch 21 on the wiring 23. The switch 22 is then located at a position λ / 4 from the open end T1 (a position λ / 2 from the stacked patch 21). With this configuration, one switch 22 can be reduced compared to the configuration in FIG. 13, thereby achieving a simpler configuration.

[0039] 15 is a diagram showing an example of a configuration in which three stacked patches 21 are connected by wiring 23. In FIG. 15, adjacent stacked patches 21 share one switch 22. Therefore, although there are three connected stacked patches 21, there are only two switches 22. In this way, connecting adjacent stacked patches 21 by wiring 23 so that they share one switch 22 is also possible even when there are four or more stacked patches 21.

[0040] (simulation) To verify the characteristics of the antenna device 1, a simulation was performed under the following conditions. Fig. 16 is a plan view illustrating the configuration used in the simulation. In this simulation, a plate-shaped ground substrate 50 having a ground surface 51 formed into a rectangle with sides of 40 mm when viewed from the front is used. The patch antenna 11 and the stacked patch 21 are arranged in a row in the normal direction of the ground substrate 50.

[0041] The parameters of this simulation are as follows: Distance between patch antenna 11 and ground plane 51: 0.5 mm Length of one side of patch antenna 11: 4.6 mm Radio waves emitted by patch antenna 11: Frequency 28 GHz (wavelength 10.7 mm)

[0042] (First simulation) In the first simulation, a preferable size of the stacked patch 21 and the stacked patch distance D1 are verified. In the first simulation, the length of one side of the stacked patch 21 is varied, and the stacked patch distance D1 between the patch antenna 11 and the stacked patch 21 is varied. FIG. 17 is a diagram illustrating the results of the first simulation. The horizontal axis of FIG. 17 illustrates the length of one side of the stacked patch 21. The vertical axis of FIG. 17 illustrates the gain (dBi). FIG. 17 also illustrates the gain when the stacked patch 21 is not provided, the gain when the stacked patch distance D1 is set to 0.5 mm, the gain when the stacked patch distance D1 is set to 1.0 mm, and the gain when the stacked patch distance D1 is set to 1.5 mm.

[0043] From the results of the first simulation illustrated in FIG. 17, it can be seen that the antenna gain is maximized when the side of the stacked patch 21 is 3.6 mm and the stacked patch distance D1 is 0.5 mm. Therefore, it is considered preferable to set the side of the stacked patch 21 to 3.6 mm and the stacked patch distance D1 to 0.5 mm. It can also be seen that when the side of the stacked patch 21 is 3.6 mm and the stacked patch distance D1 is 0.5 mm, the gain is improved by 0.4 dB compared to when the stacked patch 21 is not provided. The second to seventh simulations described below are performed with the side of the stacked patch 21 set to 3.6 mm and the stacked patch distance D1 set to 0.5 mm.

[0044] (Second simulation) In the second simulation, the gain of the antenna is verified for each of the following states: when the stacked patch 21 is not provided; when the stacked patch 21 is provided; and when adjacent stacked patches 21 are connected by the wiring 23.

[0045] FIG. 18 is a diagram illustrating a state in the second simulation where a stacked patch 21 is not provided. FIG. 18 also illustrates the position of a feed point 12 that feeds power to the patch antenna 11. FIG. 19 is a diagram illustrating a radiation pattern combined by four patch antennas 11. The radiation peak at this time faces the X direction, and the maximum antenna gain is 14.7 dBi. FIG. 20 is a diagram illustrating a state in the second simulation where a stacked patch 21 is provided. FIG. 21 is a diagram illustrating a state in the second simulation where adjacent stacked patches 21 are connected by wiring 23.

[0046] The second simulation revealed that the gain was 15.0 dB when stacked patch 21 was provided (FIG. 20), which was 0.3 dB better than when stacked patch 21 was not provided (FIG. 18). Furthermore, it was revealed that when adjacent stacked patches 21 were connected by wiring 23 (FIG. 21), the gain was 4.6 dB worse than when stacked patch 21 was provided (FIG. 20), and radio waves were suppressed. The second simulation shows that connecting adjacent stacked patches 21 by wiring 23 makes it possible to reduce the gain of the antenna.

[0047] (Third simulation) In the third simulation, the gain fluctuation according to the number of stacked patches 21 connected by the wiring 23 is verified. FIG. 22 is a diagram illustrating a state in the third simulation in which two stacked patches 21 are connected by the wiring 23. FIG. 23 is a diagram illustrating a state in the third simulation in which three stacked patches 21 are connected by the wiring 23. In addition, in the third simulation, verification is also performed on a state in which the stacked patches 21 are not connected by the wiring 23 (FIG. 20) and a state in which four stacked patches 21 are connected by the wiring 23 (FIG. 21).

[0048] When the stacked patches 21 were not connected by the wiring 23 (FIG. 20), the antenna gain was 15.0 dBi. When four stacked patches 21 were connected by the wiring 23 (FIG. 21), the antenna gain was 10.4 dBi. When two stacked patches 21 were connected by the wiring 23 (FIG. 22), the antenna gain was 13.5 dBi. When three stacked patches 21 were connected by the wiring 23 (FIG. 23), the antenna gain was 12.0 dBi. From the third simulation, it can be seen that the antenna gain can be adjusted by changing the connection of the stacked patches 21 by the wiring 23.

[0049] (Fourth simulation) In the fourth simulation, the relationship between the length of the wiring 23 connected to the stacked patch 21 and the gain of the antenna is verified. The fourth simulation verifies the case where the end of the wiring 23 connected to the stacked patch 21 is an open end T1.

[0050] 24 is a diagram schematically illustrating the relationship between the length of the wiring 23 and the current distribution in the fourth simulation. In FIG. 24, solid circles indicate locations where weak current distribution occurs, and dotted circles indicate locations where strong current distribution occurs. FIG. 24 also illustrates the length of the wiring 23 connected to the stacked patch 21.

[0051] FIG. 24A illustrates the current distribution when the wiring 23 is not connected to the stacked patch 21. FIG. 24B illustrates the current distribution when the wiring 23 with a length of λ / 4 is connected to the stacked patch 21. FIG. 24C illustrates the current distribution when the wiring 23 with a length of λ / 2 is connected to the stacked patch 21. FIG. 24D illustrates the current distribution when the wiring 23 with a length of 3λ / 4 is connected to the stacked patch 21. FIG. 24E illustrates the current distribution when the wiring 23 with a length of λ is connected to the stacked patch 21. FIG. 24F illustrates the current distribution when the wiring 23 with a length of 5λ / 4 is connected to the stacked patch 21.

[0052] When the wire 23 is not connected to the stacked patch 21 (FIG. 24A), the peak gain is 8.5 dBi (normal). When the wire 23 with a length of λ / 4 is connected to the stacked patch 21 (FIG. 24B), the peak gain is 2.1 dBi (suppression). When the wire 23 with a length of λ / 2 is connected to the stacked patch 21 (FIG. 24C), the peak gain is 7.7 dBi (normal). When the wire 23 with a length of 3λ / 4 is connected to the stacked patch 21 (FIG. 24D), the peak gain is 5.8 dBi (suppression). When the wire 23 with a length of λ is connected to the stacked patch 21 (FIG. 24E), the peak gain is 7.9 dBi (normal). When the wire 23 with a length of 5λ / 4 is connected to the stacked patch 21 (FIG. 24F), the peak gain is 6.0 dBi (suppression).

[0053] FIG. 25 is a diagram summarizing the results of the fourth simulation. The vertical axis of FIG. 25 illustrates peak gain (dBi). The horizontal axis of FIG. 25 illustrates the length of the wiring 23 connected to the stacked patch 21. As can be seen from FIG. 25, when the wiring 23 is connected to the open end T1, it is possible to suppress the antenna gain by setting the length of the wiring 23 connected to the stacked patch 21 to (2x+1) / 4λ.

[0054] (5th simulation) In the fifth simulation, a method for improving a state in which gain is degraded due to the connection of the wiring 23 by cutting a specific location of the wiring 23 is examined. FIG. 26 is a diagram schematically illustrating current distribution in the fifth simulation. In FIG. 26, solid circles indicate locations where weak current distribution occurs, and dotted circles indicate locations where strong current distribution occurs. FIG. 26 also illustrates the length of the wiring 23 connected to the stacked patch 21 and the length from the stacked patch 21 to the location where the wiring 23 is cut. In FIG. 26, the location where the wiring 23 is cut is indicated by a solid arrow. The fifth simulation examines the case in which the end of the wiring 23 connected to the stacked patch 21 is an open end T1.

[0055] 24 and 26 are associated with each other by the length of the wiring 23 connected to the stacked patch 21. FIG. 26A illustrates a state in which a wiring 23 with a length of λ / 4 is connected to the stacked patch 21. That is, FIG. 26A is a configuration corresponding to FIG. 24B. FIG. 26B illustrates a state in which a wiring 23 with a length of 3λ / 4 is connected to the stacked patch 21. That is, FIG. 26B is a configuration corresponding to FIG. 24D. FIG. 26C illustrates a state in which a wiring 23 with a length of 5λ / 4 is connected to the stacked patch 21. That is, FIG. 26C is a configuration corresponding to FIG. 24F.

[0056] 26A illustrates the current distribution when the wiring 23 is cut at the connection point of the wiring 23 to the stacked patch 21. It can be seen that by cutting the wiring 23 at the connection point, only a weak current distribution is produced in FIG. 26A, and no strong current distribution occurs. As a result, the gain, which was 2.1 dBi (suppressed) in the configuration illustrated in FIG. 24B, is improved to 8.0 dBi (normal) in the configuration illustrated in FIG. 26A.

[0057] 26B illustrates an example of a current distribution when the wiring 23 is cut at a position λ / 2 away from the stacked patch 21. By cutting the wiring 23 at a position λ / 2 away, it can be seen that only a weak current distribution is present in FIG. 26B, and no strong current distribution occurs. As a result, the gain, which was 5.8 dBi (suppressed) in the configuration illustrated in FIG. 24D, is improved to 7.8 dBi (normal) in the configuration illustrated in FIG. 26B.

[0058] 26C illustrates the current distribution when the wiring 23 is cut at a position λ away from the stacked patch 21. By cutting the wiring 23 at a position λ away, it can be seen that only a weak current distribution is present in FIG. 26C, and no strong current distribution occurs. As a result, the gain, which was 6.0 dBi (suppressed) in the configuration illustrated in FIG. 24F, is improved to 7.7 dBi (normal) in the configuration illustrated in FIG. 26C.

[0059] FIG. 27 is a diagram summarizing the results of the fifth simulation. The vertical axis of FIG. 27 illustrates peak gain (dBi). The horizontal axis of FIG. 27 illustrates the length of the wiring 23 connected to the stacked patch 21. In FIG. 27, triangles illustrate the gain improved by cutting the wiring 23. As can be seen from FIG. 27, when the length of the wiring 23 is (2x+1) / 4λ, cutting the wiring 23 at a location y / 2λ from the point where the wiring 23 is connected to the stacked patch 21 improves the gain. The values ​​of x and y are, for example, 0 when x is 0, 0 when x is 1, 0 or 1 when x is 2, or 0, 1, or 2 when x is 2.

[0060] Here, a switch 22 can be used to switch between disconnection and connection of the wiring 23. The switch 22 is disposed at a position where the wiring 23 is to be disconnected, and when disconnecting the wiring 23, the switch 22 is turned off.

[0061] (Sixth Simulation) The fourth and fifth simulations verified the case where the end of the wiring 23 is the open end T1. The sixth simulation verified the case where the end of the wiring 23 is the ground end T2.

[0062] 28 is a diagram schematically illustrating the relationship between the length of the wiring 23 and the current distribution in the sixth simulation. In FIG. 28, as in FIG. 24, solid circles indicate locations where weak current distribution occurs, and dotted circles indicate locations where strong current distribution occurs. FIG. 28 also illustrates the length of the wiring 23 connected to the stacked patch 21.

[0063] FIG. 28A illustrates the current distribution when the wiring 23 is not connected to the stacked patch 21. FIG. 28B illustrates the current distribution when the wiring 23 with a length of λ / 4 is connected to the stacked patch 21. FIG. 28C illustrates the current distribution when the wiring 23 with a length of λ / 2 is connected to the stacked patch 21. FIG. 28D illustrates the current distribution when the wiring 23 with a length of 3λ / 4 is connected to the stacked patch 21. FIG. 28E illustrates the current distribution when the wiring 23 with a length of λ is connected to the stacked patch 21. FIG. 28F illustrates the current distribution when the wiring 23 with a length of 5λ / 4 is connected to the stacked patch 21.

[0064] When the wire 23 is not connected to the stacked patch 21 (FIG. 28A), the peak gain is 8.5 dBi (typical). When the wire 23 with a length of λ / 4 is connected to the stacked patch 21 (FIG. 28B), the peak gain is 8.0 dBi (typical). When the wire 23 with a length of λ / 2 is connected to the stacked patch 21 (FIG. 28C), the peak gain is 5.1 dBi (suppression). When the wire 23 with a length of 3λ / 4 is connected to the stacked patch 21 (FIG. 28D), the peak gain is 7.4 dBi (typical). When the wire 23 with a length of λ is connected to the stacked patch 21 (FIG. 28E), the peak gain is 6.4 dBi (suppression). When the wire 23 with a length of 5λ / 4 is connected to the stacked patch 21 (FIG. 28F), the peak gain is 8.2 dBi (typical).

[0065] FIG. 29 summarizes the results of the sixth simulation. For comparison, FIG. 29 also illustrates the results of the fourth simulation. The vertical axis of FIG. 29 illustrates peak gain (dBi). The horizontal axis of FIG. 29 illustrates the length of the wiring 23 connected to the stacked patch 21. As can be seen from FIG. 29, the normal and suppressed gain are reversed depending on whether the termination of the wiring 23 is the open end T1 or the ground end T2. As can be seen from FIG. 29, when the wiring 23 is connected to the ground end T2, the antenna gain can be suppressed by setting the length of the wiring 23 connected to the stacked patch 21 to an integer multiple of λ / 2.

[0066] (Simulation 7) The first six simulations were conducted on the case where there was one pair of patch antenna 11 and stacked patch 21. In the seventh simulation, the case where there were a plurality of pairs of patch antenna 11 and stacked patch 21 was examined.

[0067] FIG. 30 illustrates a seventh simulation in which two pairs of patch antennas 11 and stacked patches 21 are arranged side by side, and each stacked patch 21 is connected by a wiring 23. FIG. 30 also illustrates the length of the wiring 23 and the length from the stacked patch 21a to the position where the wiring 23 is cut. In FIG. 30, the position where the wiring 23 is cut is illustrated by a solid arrow. In the example of FIG. 30, the length of the wiring 23 connected to the stacked patch 21a and the length of the wiring 23 connected to the stacked patch 21b are both 3λ / 2. That is, this is equivalent to a state in which an open end T1 with a wiring length of 3λ / 2 that suppresses the gain of the stacked patch 21a is connected to an open end T1 with a wiring length of 3λ / 2 that suppresses the gain of the stacked patch 21b. In a simulation under this condition, the antenna gain is 5.6 dBi, which is a suppressed state.

[0068] 30, when a simulation is performed on the condition where the wiring 23 is cut at a position λ / 2 from the stacked patch 21a, the antenna gain returns to the normal state of 8.0 dBi. In other words, when the stacked patches 21 of each of two pairs of patch antenna 11 and stacked patch 21 are connected by wiring 23, the gain can be adjusted by cutting / connecting one point of the wiring 23.

[0069] FIG. 31 illustrates a seventh simulation in which four pairs of patch antennas 11 and stacked patches 21 are arranged side by side, and adjacent stacked patches 21 are connected by wiring 23. FIG. 31 also illustrates the length of the wiring 23 connecting adjacent stacked patches 21 and the length from the stacked patch 21a to the position where the wiring 23 is cut. In FIG. 31, the position where the wiring 23 is cut is indicated by a solid arrow. In a simulation in which four pairs are arranged in this manner, the antenna gain is 5.6 dBi.

[0070] In the state illustrated in FIG. 31 , between stacked patch 21a and stacked patch 21b, the wiring 23 is cut at a position λ / 2 from stacked patch 21a. Furthermore, between stacked patch 21b and stacked patch 21c, the wiring 23 is cut at a position λ / 2 from stacked patch 21b. Furthermore, between stacked patch 21c and stacked patch 21d, the wiring 23 is cut at a position λ / 2 from stacked patch 21c. When a simulation is performed for the state in which the wiring 23 is cut in this manner, the antenna gain is 13.7 dBi. When four pairs of patch antenna 11 and stacked patch 21 are lined up and adjacent stacked patches 21 are connected by wiring 23, the gain can be adjusted by cutting / connecting the wiring 23 at three points. According to the seventh simulation, when n pairs (n is a natural number) of patch antennas 11 and stacked patches 21 are lined up and adjacent stacked patches 21 are connected with wiring 23, it can be said that the antenna gain can be adjusted by cutting / connecting at (n-1) locations.

[0071] From the simulation described above, it can be seen that the antenna device 1 can adjust the gain in response to the on / off switching of the switch 22.

[0072] <Effects of the embodiment> According to this embodiment, the stacked patch module 20 is attached from the outside of the millimeter-wave antenna module 10. Then, the gain of the antenna device 1 can be adjusted by turning on / off the switch 22 provided on the stacked patch module 20. That is, according to this embodiment, even if the millimeter-wave antenna module 10 is an existing module and access to the inside is not possible, the gain of the antenna device 1 can be adjusted.

[0073] According to this embodiment, the on / off of the switch 22 is controlled by the control device 100. That is, by installing an appropriate program in the control device 100, it is possible to control the on / off of the switch 22 according to desired conditions. The control device 100 may switch the on / off of the switch 22 according to the detection result of the sensor 105, for example.

[0074] <First Modification> The antenna device 1 according to the embodiment described above can also be implemented in, for example, a smartphone. FIG. 32 is a diagram showing an example of a smartphone 600 according to a first modified example. In FIG. 32, the antenna device 1 implemented inside the smartphone 600 is illustrated by a dotted line. The smartphone 600 includes a housing 610, a display 620, a microphone 630, and a speaker 640. The smartphone 600 is a portable wireless communication device including hardware such as that shown in FIG. 4, for example.

[0075] The smartphone 600 includes three antenna devices 1 in its housing 610. In FIG. 32, the smartphone 600 is shown equipped with three antenna devices 1, but the smartphone 600 may be equipped with two or fewer antenna devices 1, or may be equipped with four or more antenna devices 1. The smartphone 600 may also function as the control device 100 for the antenna devices 1. That is, the CPU 101 of the smartphone 600 may control the on / off of the switch 22 in accordance with a program stored in the auxiliary storage unit 103.

[0076] <Second Modification> When the antenna device 1 is implemented in a smartphone 600, it may be preferable to suppress the gain of the antenna device 1 depending on the usage status of the smartphone 600. In the second modification, a situation in which it is preferable to suppress the gain of the antenna device 1 and a method for detecting such a situation will be described.

[0077] When approaching the human body When the smartphone 600 is close to a human body (for example, a head), it is preferable to suppress the gain of the antenna device 1. The control device 100 may include, for example, a capacitance proximity sensor as the sensor 105. When the capacitance proximity sensor detects the approach of a human body, the control device 100 may suppress the gain of the antenna device 1 by turning off the switch 22. Note that the control device 100 may include an optical proximity sensor instead of the capacitance proximity sensor.

[0078] When you are on a call The control device 100 may suppress the gain of the antenna device 1 when a call is being made using the antenna device 1. The control device 100 may determine that a call is in progress when, for example, sound is being input to the microphone 630. The control device 100 may also determine that a call is in progress when, for example, sound is being output from the speaker 640. The control device 100 may also determine that a call is in progress when an application program for voice calls is being executed on the smartphone 600. When the control device 100 determines that a call is in progress, it may suppress the gain of the antenna device 1 by switching off the switch 22.

[0079] · Country-specific gain suppression Some countries have strict regulations on antenna gain, while others have looser regulations. Therefore, the control device 100 may determine whether to suppress the gain of the antenna device 1 depending on the country in which the smartphone 600 is used. For example, the control device 100 may identify the country in which the smartphone 600 is used based on a country code included in radio waves received from a base station via the antenna device 1. Then, if the laws and regulations of the identified country require gain suppression, the control device 100 may suppress the gain of the antenna device 1 by switching off the switch 22.

[0080] <Other variations> In the embodiment described above, the antenna device 1 includes four patch antennas 11 and four stacked patches 21, but the number of patch antennas 11 and stacked patches 21 is not limited to four. The antenna device 1 may include five or more patch antennas 11 and stacked patches 21. The antenna device 1 may also include three or fewer patch antennas 11 and stacked patches 21. The antenna device 1 may include, for example, one patch antenna 11 and one stacked patch 21.

[0081] The embodiments and modifications disclosed above can be combined with each other. [Explanation of symbols]

[0082] 1. Antenna device 10. Millimeter-wave antenna module 11. Patch antenna 11a··Patch antenna 11b Patch antenna 11c··Patch antenna 11d··Patch antenna 12. Power supply point 20 stacked patch modules 21 Stacked Patch 21a Stacked Patch 21b stacked patch 21c stacked patch 21d stacked patch 22 Switch 22a··switch 22b Switch 22c··switch 23 Wiring 23a Wiring 23b Wiring 23c··Wiring 23d··Wiring 24 Flexible PCB 24a...Front plate part 24b...Bottom plate part 50··Ground board 51 Ground plane 100 Control device 101 CPU 102...Main memory 103...Auxiliary storage section 104··Communications Department 105··Sensor 600··Smartphone 610··Case 620··Display 630··Microphone 640··Speaker B1 Connecting bus D1 stack patch distance T1...Open end T2··Grounding terminal

Claims

1. an antenna module including a patch antenna; a parasitic element disposed in a direction in which the patch antenna radiates radio waves; Wiring connected to the parasitic element; a switching unit that is connected to the parasitic element and is provided at a position that divides the wiring into a first portion having a length corresponding to the wavelength of the radio wave from the parasitic element and a second portion excluding the first portion, and that connects and disconnects the first portion and the second portion. Antenna device.

2. A second end of the second part opposite to the first end connected to the switching part is open, The length of the first portion is an odd multiple of a quarter wavelength of the radio wave. The antenna device according to claim 1 .

3. A second end of the second part opposite to the first end connected to the switching part is grounded, The length of the first portion is an integral multiple of half the wavelength of the radio wave. The antenna device according to claim 1 .

4. the antenna module includes a first patch antenna and a second patch antenna; the parasitic elements include a first parasitic element arranged in a direction in which the first patch antenna radiates radio waves, and a second parasitic element arranged in a direction in which the second patch antenna radiates radio waves, the wiring connects the first parasitic element and the second parasitic element; The antenna device according to claim 1 .

5. the distance between the first parasitic element and the second parasitic element is 0.5 times the wavelength of the radio wave; 5. The antenna device according to claim 4.

6. a flexible substrate including a front plate portion disposed in a direction in which the patch antenna irradiates radio waves and a bottom plate portion bonded to a bottom surface of the antenna module; the parasitic element is disposed on the front plate portion; The antenna device according to any one of claims 1 to 5.

7. Further equipped with a sensor that detects the approach of a human body, The switching unit separates the first portion from the second portion when the sensor detects the approach of the human body.

7. An antenna device according to claim 1.

8. An antenna device according to any one of claims 1 to 7, Wireless communication device.

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