Antenna device and wireless communication device

Abstract

To minimize as much as possible the mounting space for antennas compatible with multiple frequencies.SOLUTION: An antenna device of the present invention includes an antenna that is excited in a first frequency band and is positioned along a ground, and a feeder line that is connected from the ground to the antenna. The antenna has a first slot that is excited in a second frequency band different from the first frequency band. The feeder line is connected in the range of a length corresponding to roughly one fiftieth of the wavelength of radio waves at a resonant frequency from the edge of the first slot.SELECTED DRAWING: Figure 3

Description

[Technical field]

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

[0002] 2. Description of the Related Art In recent years, with the development of wireless communication technology, various antennas are used in wireless communication devices (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 250788 [Patent Document 2] Special Publication No. 2007-533194 Summary of the Invention [Problem to be solved by the invention]

[0004] Mobile terminals such as smartphones are equipped with multiple antennas to support frequencies (e.g., 5 GHz band) of various wireless communication systems such as WiFi (registered trademark) and NFC (Near Field Communication), and to support high-frequency bands such as 6 GHz band and 26 GHz band added in 4th generation mobile communication (4G) and 5th generation mobile communication (5G). On the other hand, in such mobile terminals, it is difficult to secure mounting space for mounting components such as antennas due to an increase in the number of mounted components accompanying the multi-functionalization aimed at improving user convenience, and narrowing of the frame accompanying the demands for design and larger screens. Such an issue is common to wireless communication devices that are being miniaturized.

[0005] An object of one aspect of the disclosed technique is to provide an antenna device and a wireless communication device that can minimize the mounting space required for an antenna that supports multiple frequencies. [Means for solving the problem]

[0006] One aspect of the disclosed technology is exemplified by an antenna device as follows: This antenna device includes an antenna excited in a first frequency band and arranged along a ground, and a feeder line connected from the ground to the antenna, the antenna having a first slot excited in a second frequency band different from the first frequency band, and the feeder line connected within a range of a length equivalent to approximately one-fiftieth of the wavelength of a radio wave at a resonant frequency from an edge of the first slot. Effect of the Invention

[0007] According to the disclosed technique, it is possible to minimize the mounting space required for an antenna compatible with multiple frequencies. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram illustrating an example of the appearance of a smartphone according to an embodiment. [Diagram 2] FIG. 2 is a diagram illustrating an example of a hardware configuration of the smartphone according to the embodiment. [Diagram 3] FIG. 3 is a perspective view illustrating an example of an antenna according to the embodiment. [Figure 4] FIG. 4 is a first diagram illustrating variations in the power supply position. [Diagram 5] FIG. 5 is a second diagram illustrating variations in the power supply position. [Figure 6] FIG. 6 is a diagram illustrating the radiation efficiency of the antenna when the power feed position is changed. [Figure 7] FIG. 7 is a diagram illustrating an example of the reflectance of an antenna when the power feed position is changed. [Figure 8] FIG. 8 is a Smith chart showing the characteristics of an antenna. [Figure 9] FIG. 9 is a diagram illustrating an example of an antenna according to a comparative example. [Figure 10] FIG. 10 is a diagram illustrating an example of a current distribution in the antenna according to the embodiment. [Figure 11] FIG. 11 is a diagram showing an example of a current distribution in an antenna according to a comparative example. [Figure 12] FIG. 12 is a diagram illustrating the radiation efficiency of the antenna according to the embodiment. [Figure 13] FIG. 13 is a diagram showing an example of an antenna according to the first modified example. [Figure 14] FIG. 14 is a diagram showing an example of a current distribution in the antenna according to the first modified example. [Figure 15] FIG. 15 is a diagram illustrating an example of a current distribution when the distance between the slot and the second slot is changed. [Figure 16] FIG. 16 is a diagram illustrating an example of the reflectance of the antenna when the distance in the X direction between the slot and the second slot is changed. [Figure 17] FIG. 17 is a diagram illustrating a state in which the slot and the second slot overlap when viewed in the Z direction. [Figure 18] FIG. 18 is a diagram illustrating an example of the radiation efficiency of the antenna when the parallel running distance between the slot and the second slot is changed. [Figure 19] FIG. 19 is a diagram showing an example of an antenna in which the power feed position is changed. [Figure 20] FIG. 20 is a diagram illustrating an example of the radiation efficiency of the antenna when the power feeding position is changed. [Figure 21] FIG. 21 is a diagram showing an example of an antenna according to the second modified example. [Figure 22] FIG. 22 is a diagram showing an example of a current distribution in the antenna according to the second modification. [Figure 23] FIG. 23 is a diagram illustrating an example of the reflectance of the antenna when the distance in the X direction between the slot and the second slot is changed. [Figure 24] FIG. 24 is a perspective view showing an example of an antenna according to the third modified example. [Diagram 25] FIG. 25 is a diagram illustrating the radiation efficiency of the antenna when the contacts are connected. [Figure 26]FIG. 26 is a first diagram illustrating the difference in current distribution depending on whether or not there is a slot. [Figure 27] FIG. 27 is a second diagram illustrating the difference in current distribution depending on whether or not there is a slot. [Figure 28] FIG. 28 is a third diagram illustrating the difference in current distribution depending on whether or not there is a slot. [Figure 29] FIG. 29 is a diagram illustrating the radiation efficiency of an antenna with and without a slot. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] <Embodiment> Hereinafter, an embodiment will be described with reference to the drawings, taking a smartphone as an example. Note that a wireless communication terminal, a wireless terminal, a terminal, a mobile phone, a tablet, a smartphone, and the like are collectively referred to as a smartphone. FIG. 1 is a diagram showing an example of the appearance of a smartphone 100 according to an embodiment. FIG. 1 illustrates an example of the appearance of the front side of the smartphone 100. The smartphone 100 is a portable electronic device. A speaker 111, a microphone 112, and a display 113 are provided on the front side of a housing 110. It is assumed that the upper side of the paper in FIG. 1 is the upper side of the housing 110, and the lower side of the paper is the lower side of the housing 110. Hereinafter, in this specification, the vertical direction of the housing 110 is also referred to as the Y direction, the width direction of the housing 110 perpendicular to the Y direction is also referred to as the X direction, and the thickness direction of the housing 110 is also referred to as the Z direction.

[0010] 2 is a diagram showing an example of a hardware configuration of the smartphone 100 according to the embodiment. The smartphone 100 includes a CPU 101, a main memory unit 102, an auxiliary memory unit 103, a communication The CPU 101, the main memory unit 102, the auxiliary memory unit 103, the communication unit 104, the speaker 111, the microphone 112, and the display 113 are connected to each other by a connection bus B1.

[0011] The CPU 101 is also called a microprocessor unit (MPU) or a processor. The CPU 101 is not limited to a single processor, and may have a multi-processor configuration. A single CPU 101 connected to a single socket may have a multi-core configuration. At least a part of the processing executed by the CPU 101 may be performed by a processor other than the CPU 101, for example, a dedicated processor such as a digital signal processor (DSP), a graphics processing unit (GPU), a numerical calculation processor, a vector processor, or an image processing processor. At least a part of the processing executed by the CPU 101 may be executed by an integrated circuit (IC) or other digital circuit. At least a part of the CPU 101 may include an analog circuit. The integrated circuit includes a large scale integrated circuit (LSI), an application specific integrated circuit (ASIC), and a programmable logic device (PLD). The PLD includes, for example, a field-programmable gate array (FPGA). The CPU 101 may be a combination of a processor and an integrated circuit. The combination is called, for example, a microcontroller unit (MCU), a system-on-a-chip (SoC), a system LSI, a chipset, etc. In the smartphone 100, the CPU 101 deploys a program stored in the auxiliary memory unit 103 in a working area of ​​the main memory unit 102, and controls peripheral devices through the execution of the program. This enables the smartphone 100 to execute processing that matches a predetermined purpose. The main memory unit 102 and the auxiliary memory unit 103 are recording media that the smartphone 100 can read.

[0012] The main storage unit 102 is exemplified as a storage unit directly accessed by the CPU 101. The main storage unit 102 includes a Random Access Memory (RAM) and a Read Only Memory (ROM).

[0013] The auxiliary storage unit 103 stores various programs and various data in a readable and writable recording medium. The auxiliary storage unit 103 is also called an external storage device. An operating system (OS), various programs, various tables, and the like are stored in the auxiliary storage unit 103. The OS includes a communication interface program that transfers data with external devices and the like connected via the communication unit 104. The external devices and the like include, for example, other information processing devices and external storage devices connected via a computer network or the like.

[0014] The auxiliary storage unit 103 is, for example, an erasable programmable ROM (EPROM), a solid state drive (SSD), a hard disk drive (HDD), etc. Note that the auxiliary storage unit 103 may be, for example, a part of a cloud system which is a group of computers on a network.

[0015] The communication unit 104 performs wireless communication with wireless communication devices such as other mobile devices and base stations using the antenna 200. The communication unit 104 performs wireless communication using the antenna 200 by a communication method conforming to communication standards such as fourth generation mobile communication (4G), fifth generation mobile communication (5G), and WiFi (registered trademark). The antenna 200 may be formed as a part of the housing 110 of the smartphone 100, or may be housed inside the housing 110.

[0016] The speaker 111 is a sound source that outputs sound. The speaker 111 outputs sound such as the voice of a call partner during a call using the smartphone 100. The microphone 112 is used to capture sound during a call or video.

[0017] The display 113 displays data processed by the CPU 101 and data stored in the main memory unit 102. The display 113 is, for example, a Liquid Crystal Display (LCD), a Plasma Display Panel (PDP), an inorganic electroluminescence (EL) panel, or an organic EL panel. For example, a touch panel that detects a touch operation by a user's finger or the like may be provided superimposed on the display 113. By providing a touch panel superimposed on the display 113, the smartphone 100 can provide the user with an intuitive operating environment.

[0018] 3 is a perspective view showing an example of an antenna 200 according to an embodiment. The antenna 200 is formed, for example, in a part of the housing 110. The antenna 200 includes an antenna element 201, a feeding point 211, a substrate 221, and a ground 222.

[0019] Antenna element 201 is, for example, an antenna provided at an end of ground 222 formed in a rectangular shape. Antenna element 201 is provided along end surface 223 of ground 222. Board 221 is a printed circuit board on which various electronic components are mounted. Ground 222 is a metal layer formed of copper foil or the like on board 221. The potential of ground 222 is the earth potential.

[0020] Antenna element 201 is, for example, an inverted F-shaped antenna formed in the shape of a rectangular parallelepiped plate. Antenna element 201 receives power from power feed point 12 and is excited (oscillated) by radio waves in the 4G frequency band. The length of antenna element 201 in the X direction is, for example, a quarter wavelength of radio waves of a desired frequency or a quarter wavelength of radio waves of a desired frequency multiplied by a wavelength shortening rate (for example, 0.4). In the following explanation, it is assumed to be a quarter wavelength of a radio wave of a desired frequency. The antenna element 201 has a slot 202 formed therein.

[0021] The slot 202 is a through hole formed so as to penetrate the antenna element 201 in the Y direction. For example, the slot 202 is formed in a rectangle having a long side in the X direction and a short side in the Z direction when viewed in the Y direction (from the Y-axis direction). The length (width) of the slot 202 in the X direction is a half wavelength of a radio wave of a desired frequency to be resonated in the slot 202. Here, since it is preferable to excite the slot 202 in a frequency band different from that of the antenna element 201, for example, the slot 202 is designed to resonate in a frequency band different from a multiple (or an integer multiple, an odd multiple, or an even multiple) of the resonant frequency of the antenna element 201. For example, the length of the slot 202 in the X direction is set to 28 mm (a length equivalent to a half wavelength of a radio wave of 5100 MHz) so as to be excited by a radio wave of 5100 MHz. The following description will be given for the case of 5100 MHz. Note that, in the case of a frequency other than 5100 MHz, the length may be set to correspond to the other frequency. The length (height) of slot 202 in the Z direction is, for example, 1 mm. For simplicity, the slot is described as being rectangular here, but slot 202 may have any shape (hollowed-out shape) in which an area enclosed by at least one of straight lines and curves is removed, and may be, for example, a trapezoid, ellipse, circle, rectangle (sawtooth shape), L-shape, etc.

[0022] A feed line extending from a feed point 211 is connected near the slot 202. The feed line is connected on the antenna element 201 within a range L1 that overlaps with the long side of the slot 202 when viewed in the Z direction (as viewed from the Z axis direction). In other words, the antenna 200 is connected to the antenna element 201 within a range L1 that overlaps with the long side of the slot 202 when viewed in the short side direction of the slot 202 (as viewed from the short side direction). 3, for example, a feed line is connected to the back surface of the feed position 203. The feed position 203 is provided within a range of 1 mm in the -Z direction from the long side (edge) of the slot 202 on the -Z side.

[0023] <Power supply location considerations> Here, the power feeding position to antenna 200 will be considered. Fig. 4 is a first diagram illustrating variations of the power feeding position. Fig. 4 illustrates a case where power feeding position 203 is arranged within a range overlapping with the long side of slot 202 when viewed in the Z direction (range L1 in Fig. 3). In Fig. 4A, power feeding position 203 is arranged at a position 0 mm from the end of slot 202 on the -X side. In Fig. 4B, power feeding position 203 is arranged at a position +6 mm from the end of slot 202 on the -X side. In Fig. 4C, power feeding position 203 is arranged at a position +12 mm from the end of slot 202 on the -X side.

[0024] Fig. 5 is a second diagram illustrating variations of the power feeding position. Fig. 5 illustrates a case where the power feeding position 203 is arranged outside the range overlapping with the long side of the slot 202 when viewed in the Z direction (range L1 in Fig. 1). In Fig. 5A, the power feeding position 203 is arranged at a position -1 mm from the end of the -X side of the slot 202. In Fig. 5B, the power feeding position 203 is arranged at a position -2.5 mm from the end of the -X side of the slot 202.

[0025] Fig. 6 is a diagram illustrating the radiation efficiency of antenna 200 when feeding position 203 is changed. Fig. 6 illustrates a case where feeding position 203 is disposed within a range overlapping with the long side of slot 202 when viewed in the Z direction (range L1 in Fig. 3). Fig. 6 illustrates excitation by antenna element 201 (illustrated by the arrow labeled "monopole excitation") and excitation by slot 202 (illustrated by the arrow labeled "first slot excitation").

[0026] Fig. 7 is a diagram illustrating the reflectance of antenna 200 when the feeding position is changed. Fig. 7 illustrates a case where feeding position 203 is arranged outside the range overlapping with the long side of slot 202 when viewed in the Z direction (outside range L1 in Fig. 3). Fig. 7 illustrates excitation by antenna element 201 (illustrated by the arrow of "monopole excitation") and excitation by slot 202 (illustrated by the arrow of "first slot excitation").

[0027] 6 and 7, it can be seen that excitation by slot 202 can be suitably obtained within a range overlapping with the long side of slot 202 when viewed in the Z direction (range L1 in FIG. 3). Here, when the position of power feeding position 203 is changed, the slot length excited in slot 202 changes, so the position of power feeding position 203 can be determined according to the desired frequency at which slot 202 is excited.

[0028] <Matching of antenna 200> FIG. 8 is a Smith chart showing the characteristics of the antenna 200. Referring to FIG. 8, it can be seen that the impedances (50 ohms) of the antenna element 201 and the slot 202 are close to each other by setting the resonant frequency at the excitation of the slot 202 to a value close to an odd multiple of the resonant frequency at the excitation of the antenna element 201. That is, by setting the resonant frequency at the excitation of the slot 202 to a value close to an odd multiple of the resonant frequency at the excitation of the antenna element 201, impedance matching (hereinafter referred to as matching) of the antenna element 201 can also be matched for the slot 202. Note that, as a value close to an odd multiple of the resonant frequency, for example, a value within a range of about 5% to 10% from the value of an odd multiple of the resonant frequency can be cited. Note that if matching is not achieved (mismatching), power loss occurs in the connection between the antenna and an element (for example, a filter, an amplifier, etc.) connected to the antenna. For this reason, matching is necessary.

[0029] <Comparative Example> A comparative example will now be described. Fig. 9 is a diagram showing an example of an antenna 500 according to the comparative example. In the antenna 500, a rectangular slot 502 is provided in a plate-like member 501 formed in a wide surface shape. The power supply to the antenna 500 is performed from one long side of the slot 502 to the other long side by receiving power from a power supply position 511.

[0030] <Current distribution> FIG. 10 is a diagram showing an example of a current distribution of the antenna 200 according to the embodiment. In FIG. 10, the position of the power feed position 203 is illustrated by an arrow of "power feed position". When power is fed from the power feed point 211, a current flowing in the +X direction from the power feed position 203 and a current flowing in the -X direction are generated on the -Z side of the slot 202. In addition, in the +Z side region of the slot 202, a current in the opposite direction to that in the -Z side region of the slot 202 is generated by electrostatic induction of the current generated in the -Z side region. As illustrated by arrows A1 and A2, the current generated in the -Z side region and the current generated in the +Z side region are in the same direction at both ends of the slot 202 in the X direction, forming a current path that turns back. By turning back the current in this way, it is possible to obtain excitation by the slot 202 at a frequency according to the distance from the power feed position 203 to the end of the slot 202 in the X direction. That is, the antenna 200 is an antenna that can obtain excitation by the antenna element 201 and excitation by the slot 202.

[0031] 11 is a diagram showing an example of current distribution in an antenna 500 according to a comparative example. In the antenna 500, a current fed from a feeding position 511 flows on a plate-like member 501, and generates a current returning from one long side to the other long side. That is, the antenna 200 according to the embodiment and the antenna 500 according to the comparative example differ in the positional relationship between the position at which the antenna element is fed and the slot, and in the mechanism by which excitation is generated by the slot.

[0032] Fig. 12 is a diagram illustrating the radiation efficiency of the antenna 200 according to the embodiment. Fig. 12 also illustrates an antenna in which the slot 202 is omitted from the antenna 200 ("no slot" in Fig. 7). Fig. 11 illustrates excitation at a reference frequency (illustrated by an arrow "x1"), excitation at three times the frequency (illustrated by an arrow "x3"), and excitation at five times the frequency (illustrated by an arrow "x5"). It can be seen that the antenna 200 further provides excitation by the slot 202 (illustrated by an arrow "first slot excitation").

[0033] <Effects of the embodiment> According to this embodiment, in addition to excitation by antenna element 201, excitation by slot 202 can also be obtained. That is, according to this embodiment, it is possible to realize an antenna that can obtain excitation by antenna element 201 and excitation by slot 202 in the space in which antenna element 201 is installed. In other words, according to this embodiment, it is possible to realize an antenna that supports a plurality of frequencies, and it is possible to reduce the mounting space for the antenna as much as possible.

[0034] In this embodiment, the impedances of the antenna element 201 and the slot 202 are close to each other by setting the resonant frequency at the excitation of the slot 202 to a value close to an odd multiple of the resonant frequency at the excitation of the antenna element 201. In other words, by setting the resonant frequency at the excitation of the slot 202 to a value close to an odd multiple of the resonant frequency at the excitation of the antenna element 201, matching of the slot 202 can be achieved by matching the antenna element 201. In other words, it is no longer necessary to achieve matching for the slot 202 and matching for the antenna element 201 separately, and it is only necessary to achieve matching for the antenna 200 including the antenna element 201 and the slot 202. This makes it easier to achieve matching.

[0035] <First Modification> In the embodiment, one slot 202 is provided in the antenna element 201. In the first modified example, a configuration in which two slots are provided in the antenna element 201 will be described. Components common to the embodiment will be denoted by the same reference numerals, and descriptions thereof will be omitted. Hereinafter, the first modified example will be described with reference to the drawings.

[0036] FIG. 13 is a diagram showing an example of an antenna 200A according to a first modified example. FIG. 13 illustrates an external view of the antenna 200A viewed in the Y direction. The antenna 200A includes a second slot 202A in addition to the slot 202. The length of the second slot 202A in the X direction is set to a half wavelength of a desired frequency to be excited. The length of the second slot 202A in the X direction is set to 25 mm (a length equivalent to a half wavelength of a 5500 MHz radio wave) so as to be excited by a 5500 MHz radio wave, for example. The second slot 202A is an example of a "second slot". The following description will be given for the case of 5500 MHz. In addition, in the case of a frequency other than 5500 MHz, the length may be set to correspond to the other frequency.

[0037] In antenna 200A, slot 202 and second slot 202A are arranged with a shift in the Z direction. That is, slot 202 and second slot 202A are not arranged on the same straight line. In the example of Fig. 13, second slot 202A is arranged outside the area overlapping with slot 202 when viewed in the long side direction of slot 202 (viewpoint from the long side direction, view from the X direction, view from the X axis direction). Then, distance D1 in the X direction between slot 202 and second slot 202A (distance between slot 202 and second slot 202A) is set to, for example, 1 mm.

[0038] Fig. 14 is a diagram showing an example of current distribution of antenna 200A according to the first modification. In Fig. 14, the position of power feeding position 203 is illustrated by the arrow "power feeding position". Fig. 14A illustrates the current flow near slot 202 in the current distribution of antenna 200A by arrows A3 and A4. Fig. 14B illustrates the current flow near second slot 202A in the current distribution of antenna 200A by arrows A5, A6, and A7.

[0039] 14A, when power is fed to feeding position 203 of antenna 200A, a current is generated in the +Z side region of slot 202 in the opposite direction to that in the -Z side region of slot 202 due to electrostatic induction of a current generated in the -Z side region. Then, the current generated in the +X direction and -X direction on the -Z side of slot 202 is folded back at both ends of slot 202 in the X direction, as exemplified by arrows A3 and A4.

[0040] 14B, as illustrated by arrow A5, the current generated on the -Z side of slot 202 also flows to the -Z side of second slot 202A. Then, in the +Z side region of second slot 202A, a current flows in the opposite direction to the -Z side region of second slot 202A due to electrostatic induction of the current generated in the -Z side region. Then, the current flowing on the -Z side of second slot 202A turns back at both ends of second slot 202B in the X direction, as illustrated by arrows A6 and A7.

[0041] By folding back the current in this way, excitation by slot 202 can be obtained at a frequency according to the distance from power feeding position 203 to the end of slot 202 in the X direction. Also, excitation by second slot 202A can be obtained at a frequency according to the length of second slot 202A. In other words, antenna 200A is an antenna that can obtain excitation by antenna element 201, excitation by slot 202, and excitation by second slot 202A.

[0042] Here, the distance in the X direction between the slot 202 and the second slot 202A will be considered. Fig. 15 is a diagram illustrating an example of a current distribution when the distance D1 between the slot 202 and the second slot 202A is changed. Fig. 15A is a diagram illustrating a current distribution when the distance D1 between the slot 202 and the second slot 202A is changed. 15A is a diagram illustrating an example of a current distribution when the distance D1 between the slot 202 and the second slot 202A is 0 mm. Fig. 15B is a diagram illustrating an example of a current distribution when the distance D1 between the slot 202 and the second slot 202A is 2 mm.

[0043] When distance D1 is 0 mm, the current generated on the -Z side of slot 202 also flows to the -Z side of second slot 202A, as illustrated by arrow A8 in Fig. 15A. On the other hand, when distance D2 is 2 mm, the current turns back at the end of slot 202 on the +X side, as illustrated by arrow A9 in Fig. 15B, and little current flows into the -Z side of second slot 202A.

[0044] Fig. 16 is a diagram illustrating the reflectance of antenna 200A when distance D1 in the X direction between slot 202 and second slot 202A is changed. Fig. 16 illustrates the reflectance when distance D1 is set to "0 mm", "0.5 mm", "1.0 mm", "1.5 mm", and "2.0 mm". Fig. 16 also illustrates excitation by slot 202 (illustrated by the arrow "first slot excitation") and excitation by second slot 202A (illustrated by the arrow "second slot excitation").

[0045] 16, it can be seen that in the excitation by the slot 202 and the excitation by the second slot 202A, a shorter distance D1 between the slots 202 can provide more suitable excitation. Considering the excitation by the slot 202 and the excitation by the second slot 202A, for example, the distance D1 is preferably 1.0 mm (a length equivalent to 1 / 55th of the wavelength of a 5500 MHz radio wave) or less.

[0046] Next, a case where the slot 202 and the second slot 202A overlap when viewed in the Z direction will be considered. Fig. 17 is a diagram illustrating a state where the slot 202 and the second slot 202A overlap when viewed in the Z direction. In Fig. 17, the slot 202 and the second slot 202A overlap by a distance D2 when viewed in the Z direction. Hereinafter, in this specification, the distance D2 by which the slot 202 and the second slot 202A overlap when viewed in the Z direction will also be referred to as the parallel running distance D2.

[0047] Fig. 18 is a diagram illustrating the radiation efficiency of antenna 200A when the parallel distance D2 between slot 202 and second slot 202A is changed. Fig. 18 illustrates the radiation efficiency when parallel distance D2 is set to "0 mm", "5 mm", "10 mm", and "15 mm". Fig. 18 also illustrates the excitation by slot 202 (illustrated by the arrow "first slot excitation") and the excitation by second slot 202A (illustrated by the arrow "second slot excitation").

[0048] 18, it can be seen that the resonance frequency of the slot 202 and the second slot 202A changes by changing the parallel distance D2. It can also be seen that the slot 202 and the second slot 202A can be excited regardless of whether the parallel distance D2 is set to "0 mm," "5 mm," "10 mm," or "15 mm."

[0049] Next, the position of the power feed position 203 will be considered. Fig. 19 is a diagram showing an example of antenna 200A in which the position of power feed position 203 has been changed. Fig. 19 illustrates a state in which power feed position 203 is arranged on the +Z side of slot 202. Note that Fig. 13 above illustrates a state in which power feed position 203 is arranged on the -Z side of slot 202.

[0050] 20 is a diagram illustrating the radiation efficiency of the antenna 200A when the power feed position is changed. In FIG. 20, the state where the power feed position 203 is disposed on the -Z side of the slot 202 (the state illustrated in FIG. 13) is illustrated as "power feed point -Z". 2 (the state illustrated in FIG. 19) is illustrated as "feed point +Z". With reference to FIG. 20, it can be seen that the characteristics of slot 202 and second slot 202A are more preferable when feed position 203 is arranged on the -Z side of slot 202. In other words, the characteristics of slot 202 and second slot 202A are more preferable when feed position 203 is provided at a position away from second slot 202A in the Z direction. It can also be seen that slot 202 and second slot 202A can be excited regardless of whether feed position 203 is arranged on the -Z side or +Z side of slot 202.

[0051] According to the first modification, in addition to excitation by antenna element 201 and excitation by slot 202, excitation by second slot 202A can also be obtained. That is, according to the first modification, it is possible to realize an antenna in which excitation by slot 202 and excitation by second slot 202A can also be obtained in the space in which antenna element 201 is installed.

[0052] <Second Modification> In the first modified example, a configuration in which the two slots, the slot 202 and the second slot 202A, are not aligned on the same straight line is described. In the second modified example, a configuration in which the two slots are aligned on the same straight line is described. Components common to the embodiment are given the same reference numerals, and descriptions thereof are omitted. The second modified example will be described below with reference to the drawings.

[0053] Fig. 21 is a diagram showing an example of an antenna 200B according to a second modified example. Fig. 21 illustrates an external view of the antenna 200B viewed in the Y direction. The antenna 200B includes a second slot 202B in addition to the slot 202. The length of the second slot 202B in the X direction is set to a half wavelength of a desired frequency to be excited. For example, the length of the second slot 202B in the X direction is set to 25 mm (a length equivalent to a half wavelength of a 5500 MHz radio wave) so that it is excited by a 5500 MHz radio wave.

[0054] In the antenna 200B, the slot 202 and the second slot 202B are arranged on the same straight line in the X direction. In other words, the slot 202 and the second slot 202B are arranged to be aligned in a row along the long side direction of the slot 202. A distance D3 between the slot 202 and the second slot 202B in the X direction is set to, for example, 1 mm.

[0055] Fig. 22 is a diagram showing an example of a current distribution of an antenna 200B according to a second modified example. In Fig. 22, the position of the power feeding position 203 is illustrated by an arrow of "power feeding position". Fig. 22A illustrates the current distribution when the distance D3 is set to 0.5 mm. Fig. 22B illustrates the current distribution when the distance D3 is set to 2.0 mm.

[0056] 22A, when power is fed to feeding position 203 of antenna 200A, the current generated in the +X and -X directions on the -Z side of slot 202 also flows to the -Z side of second slot 202B, as illustrated by arrow A10. On the other hand, with reference to Fig. 22B, as illustrated by arrow A11, the current generated in the +X direction on the -Z side of slot 202 is turned back at the end of slot 202 on the +X side, and little current flows into the -Z side of second slot 202B.

[0057] Fig. 23 is a diagram illustrating the reflectance of antenna 200B when distance D3 in the X direction between slot 202 and second slot 202B is changed. Fig. 23 illustrates the reflectance when distance D3 is set to "0.5 mm", "1.0 mm", "1.5 mm", and "2.0 mm". Fig. 23 also illustrates excitation by slot 202 (illustrated by the arrow "first slot excitation") and excitation by second slot 202B (illustrated by the arrow "second slot excitation").

[0058] 23, it can be seen that in the excitation by the slot 202 and the excitation by the second slot 202B, the narrower the distance D2 between the slot 202 and the second slot 202B, the more suitable the excitation can be obtained. In consideration of the excitation by the slot 202 and the excitation by the second slot 202B, the distance D3 is preferably, for example, 1.0 mm or less (a length equivalent to 1 / 55th of the wavelength of a 5500 MHz radio wave).

[0059] According to the second modification, in addition to the excitation by antenna element 201 and the excitation by slot 202, excitation by second slot 202B can also be obtained. That is, according to the second modification, it is possible to realize an antenna in which excitation by slot 202 and excitation by second slot 202B can also be obtained in the space in which antenna element 201 is installed.

[0060] <Third Modification> In the above-described embodiment, the first modified example, and the second modified example, the second slot to which the power feed point 211 is not connected is not connected to the ground 222. In the third modified example, a configuration will be described in which the power feed point 211 is connected to the ground 222 via a contact point with the second slot to which the power feed point 211 is not connected.

[0061] 24 is a perspective view showing an example of an antenna 200C according to a third modified example. In the antenna 200C, the second slot 202A and the ground 222 are connected by a contact 231. The contact 231 may be, for example, an inductor or a capacitor. The contact 231 is an example of a "frequency adjuster."

[0062] FIG. 25 is a diagram illustrating the radiation efficiency of the antenna 200C by connecting (loading) the contact 231. FIG. 25A illustrates the radiation efficiency when the contact 231 is not connected. FIG. 25B illustrates the radiation efficiency when the 100nH contact 231 is connected. FIG. 25C illustrates the radiation efficiency when the 15nH contact 231 is connected. FIG. 25D illustrates the radiation efficiency when the 6.8nH contact 231 is connected. FIG. 25 also illustrates the excitation by the antenna element 201 (illustrated by the arrow of "monopole excitation"), the excitation by the slot 202 (illustrated by the arrow of "first slot excitation"), and the excitation by the second slot 202A (illustrated by the arrow of "second slot excitation").

[0063] 25, it can be seen that the resonant frequency of the antenna element 201 and the second slot 202A varies depending on the inductance of the connecting contact 231. That is, in the third modified example, the resonant frequency of the antenna element 201 and the second slot 202A can be adjusted (controlled) by appropriately setting the inductance of the connecting contact 231. Note that, although the resonant frequency is adjusted using an inductor here, it may be adjusted using a capacitor, or may be adjusted using an inductor and a capacitor.

[0064] <Study of the effect of the presence or absence of slot 202> Although the embodiment and the modified example have been described above, the effect of the presence or absence of the slot 202 will be examined here. Figs. 26 to 28 are diagrams illustrating the difference in current distribution depending on the presence or absence of the slot 202. Fig. 26 illustrates the current distribution of the antenna 200 provided with the slot 202. Fig. 27 illustrates the current distribution of the antenna 300 in which the second slot 202A is provided but the slot 202 is omitted. Fig. 28 illustrates the current distribution of the antenna 200A in which the slot 202 and the second slot 202A are provided. Fig. 28A illustrates the excitation in the slot 202 of the antenna 200A. Fig. 28B illustrates the excitation in the second slot 202A of the antenna 200A.

[0065] With reference to FIG. 26, it can be seen that the excitation of the slot 202 is obtained as illustrated by the arrow A12. The slot 202 is, for example, excited at a frequency of 5100 MHz. 27, it can be seen that in the antenna 300 in which the slot 202 is omitted, the slot 202 is not excited, and the second slot 202A is not excited either. With reference to FIG. 28A, it can be seen that the slot 202 is excited, as illustrated by the arrow A13. The slot 202 is excited, for example, at a frequency of 5100 MHz. With reference to FIG. 28B, a current is transmitted from the slot 202 to the second slot 202A, as illustrated by the arrow A14. Then, the second slot 202A is excited, as illustrated by the arrow A15. The second slot 202A is excited, for example, at a frequency of 5500 MHz.

[0066] Fig. 29 illustrates the radiation efficiency of an antenna with and without a slot 202. Fig. 29A illustrates the radiation efficiency of an inverted-F antenna without a slot. Fig. 29B illustrates the radiation efficiency of an antenna 200 with a slot 202. Fig. 29C illustrates the radiation efficiency of an antenna 300 with a second slot 202A but without the slot 202. Fig. 29D illustrates the radiation efficiency of an antenna 200A with a slot 202 and a second slot 202A.

[0067] 26 to 29, by providing slot 202 receiving power, it is possible to obtain excitation of the slot in antenna 200 or antenna 200A. That is, according to this embodiment and the modified example, it is possible to realize an antenna that obtains excitation by slots such as slot 202, second slot 202A, and second slot 202B within the space in which antenna element 201 is installed.

[0068] In the above-described embodiment and modified example, the antenna element 201 has been described as an inverted-F antenna, but the antenna element 201 may be a monopole antenna. The antenna 200 is not limited to the smartphone 100, and can be applied to a wireless communication terminal (wireless terminal, terminal) exemplified by the smartphone 100. Examples of wireless communication devices other than the smartphone 100 include a base station, a relay that relays communication between a base station and a terminal, a feature phone, a tablet terminal, and a wearable computer.

[0069] In the above-described embodiment and modified example, the antenna 200 having a slot (slot 202) for receiving power and the antennas 200A and 200B having one slot (second slot 202A or second slot 202B) in addition to the slot 202 are exemplified. However, the antennas 200, 200A, 200B, and 200C may have another slot excited at a frequency different from that of the slot 202 and the second slots 202A and 202B in addition to the second slot 202A or second slot 202B. That is, the antennas 200, 200A, 200B, and 200C may have three or more slots. By having three or more slots, the antennas 200, 200A, 200B, and 200C can operate as antennas compatible with a wider range of frequency bands.

[0070] In the above-described embodiment and modified examples, a rectangular slot has been described, but the slot 202 may have any shape that excites vibration in the same way as a rectangle and has a shape in which an area enclosed by straight lines and / or curves has been removed (hollowed out). For example, the slot may be a square, trapezoid, ellipse, circle, rectangle (sawtooth shape), L-shape, etc.

[0071] The embodiments and modifications disclosed above can be combined with each other. [Explanation of symbols]

[0072] 100·Smartphone 101··CPU 102...Main memory 103...Auxiliary storage section 104 Communications Department 110··Housing 111··Speaker 112 Microphone 113··Display 200··Antenna 200A··Antenna 200B··Antenna 200C··Antenna 201 Antenna element 202··Slots 202A··Second slot 202B 2nd slot 203 Power supply position 211··Power supply point 221··Substrate 222 Grand 223...end face 231··Contact 300··Antenna 500··Antenna 501 Plate-shaped member 502··Slots 511··Power supply position

Claims

1. an antenna excited in a first frequency band and disposed along the ground; a feeder line connected from the ground to the antenna, the antenna has a first slot excited in a second frequency band different from the first frequency band; the feed line is connected within a range of a length corresponding to one fiftieth of the wavelength of a radio wave at a resonant frequency from an edge of the first slot. Antenna device.

2. a second slot is further formed in the antenna, the second slot being excited in a third frequency band different from the first frequency band and the second frequency band; The antenna device according to claim 1 .

3. The first slot is formed so that a height direction is shorter than a width direction perpendicular to the height direction, The first slot and the second slot are arranged to be aligned in a line along the width direction of the first slot. The antenna device according to claim 2 .

4. The first slot is formed so that a height direction is shorter than a width direction perpendicular to the height direction, the second slot is disposed outside a region of the first slot that overlaps with the first slot when viewed in the width direction; The antenna device according to claim 2 .

5. the second slot and the ground are connected by a frequency adjustment unit; The antenna device according to claim 2 .

6. the frequency adjusting unit includes a capacitor or an inductor; 6. The antenna device according to claim 5.

7. The second frequency band is a frequency band different from a frequency band that is a multiple of the first frequency band. The antenna device according to claim 1 .

8. a difference between a fourth frequency band among the frequencies that are odd multiples of the first frequency band and the second frequency band is within a range of 10% or less of the first frequency band; The antenna device according to claim 1 .

9. The first slot is formed so that a height direction is shorter than a width direction perpendicular to the height direction, the power supply line is connected to a region overlapping with the first slot when viewed in the height direction; The antenna device according to claim 1 .

10. An antenna device according to any one of claims 1 to 9, Wireless communication device.

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