JP7618022B2 - Antenna and wireless communication device - Google Patents

Description

The present disclosure relates to an antenna and a wireless communication device.

There is a known technology for connecting an antenna to an electronic device with a cable. For example, Patent Document 1 discloses a technology for making the magnetic field from the antenna less susceptible to the influence of the cable by positioning the antenna on a surface opposite the cable outlet surface.

JP 2003-46320 A

The antenna according to the present disclosure includes an antenna unit and a coaxial cable having one end connected to the antenna unit and the other end connected to an external device, the antenna unit including a first conductor extending in a first surface direction, a second conductor extending in the first surface direction facing a first end of the first conductor in the first direction and connected to the first conductor, a third conductor extending in the first surface direction aligned with the second conductor in the first direction facing a second end of the first conductor and connected to the first conductor, and at least one fourth conductor extending in the first surface direction and positioned apart from the second conductor and the third conductor between the second conductor and the third conductor in the first direction, the coaxial cable being connected to a connection point located in a position shifted in the first direction from the center of the antenna unit in the first direction, extending in the first surface direction toward the center in the first direction, and being drawn out to the outside of the antenna unit from between the center of the first direction and the connection point.

The antenna according to the present disclosure includes an antenna unit and a coaxial cable having one end connected to the antenna unit and the other end connected to an external device, the antenna unit including a first conductor extending in a first surface direction, a second conductor extending in the first surface direction facing a first end of the first conductor in the first direction and connected to the first conductor, a third conductor extending in the first surface direction aligned with the second conductor in the first direction facing a second end of the first conductor and connected to the first conductor, and at least one fourth conductor extending in the first surface direction and positioned apart from the second conductor and the third conductor between the second conductor and the third conductor in the first direction, the coaxial cable being connected to a connection point located in a position shifted in the first direction from the center of the antenna unit in the first direction, and extending in the first surface direction in a direction opposite to the direction toward the center of the first direction and pulled out to the outside of the antenna unit from a position in the opposite direction to the center of the first direction or extending in a direction toward the center of the first direction and exceeding the center of the first direction.

The wireless communication device according to the present disclosure comprises an antenna according to the present disclosure and a controller that controls the antenna and communicates with an external electronic device.

FIG. 1 is a diagram illustrating an example of the configuration of an antenna according to an embodiment. FIG. 2 is a diagram showing a configuration example of an upper conductor of the antenna according to the embodiment. FIG. 3 is a diagram showing a configuration example of a bottom conductor of the antenna according to the embodiment. FIG. 4 is a diagram for explaining a method of arranging the coaxial cable so that it does not act as an antenna. FIG. 5 is a diagram for explaining a method of arranging the first conductor of the coaxial cable outside. FIG. 6 is a diagram for explaining a layout method for making the coaxial cable act as an antenna. FIG. 7 is a diagram for explaining a layout method for making the coaxial cable act as an antenna. FIG. 8A is a diagram for explaining an antenna model according to the embodiment. FIG. 8B is a diagram for explaining an antenna model according to the embodiment. FIG. 8C is a diagram for explaining an antenna model according to the embodiment. FIG. 9 is a graph for explaining a simulation result of the antenna radiation efficiency in free space. FIG. 10 is a graph for explaining a simulation result of the antenna radiation efficiency on a metal. FIG. 11 is a diagram for explaining the angle at the position of the power feed point of the coaxial cable. FIG. 12 is a graph for explaining the results of a simulation of the antenna radiation efficiency depending on the angle at which the coaxial cable is led out from the antenna unit in free space. FIG. 13 is a graph for explaining the results of a simulation of the antenna radiation efficiency depending on the angle at which the coaxial cable is led out from the antenna unit in free space. FIG. 14 is a diagram showing an antenna model in which the coaxial cable is bent after being pulled out from the antenna portion. FIG. 15 is a graph for explaining a change in antenna radiation efficiency when the coaxial cable is bent when being drawn out from the antenna portion in free space. FIG. 16 is a block diagram illustrating an example of the configuration of a wireless communication device according to the embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the attached drawings. Note that the present invention is not limited to this embodiment, and in the following embodiments, the same parts are designated by the same reference numerals to avoid redundant description.

In the following explanation, an XYZ Cartesian coordinate system is set, and the positional relationship of each part is explained with reference to this XYZ Cartesian coordinate system. The direction parallel to the X-axis in a horizontal plane is defined as the X-axis direction, the direction parallel to the Y-axis in the horizontal plane perpendicular to the X-axis is defined as the Y-axis direction, and the direction parallel to the Z-axis perpendicular to the horizontal plane is defined as the Z-axis direction. A plane including the X-axis and Y-axis is appropriately referred to as the XY plane. A plane including the X-axis and Z-axis is appropriately referred to as the XZ plane. A plane including the Y-axis and Z-axis is appropriately referred to as the YZ plane. The XY plane is parallel to the horizontal plane. The XY plane, XZ plane, and YZ plane are perpendicular to each other.

[Embodiment]
An example of the configuration of an antenna according to an embodiment will be described with reference to Fig. 1, Fig. 2, and Fig. 3. Fig. 1 is a diagram showing an example of the configuration of an antenna according to an embodiment. Fig. 2 is a diagram showing an example of the configuration of an upper conductor of an antenna according to an embodiment. Fig. 3 is a diagram showing an example of the configuration of a lower conductor of an antenna according to an embodiment.

As shown in Fig. 1 to Fig. 3, the antenna 1 includes a first conductor 10, a second conductor 12, a third conductor 14, a fourth conductor 16, a first connecting conductor _20-1 , a first connecting conductor _20-2 , a second connecting conductor _22-1 , a second connecting conductor _22-2 , a power supply conductor 24, a coaxial cable 30, and a metal member 40. The first conductor 10, the second conductor 12, the third conductor 14, the fourth conductor 16, the first connecting conductor _20-1 , the first connecting conductor _20-2 , the second connecting conductor 22-1, and the second connecting conductor _22-2 are sometimes called an antenna part. The first connecting conductor _20-1 and the first connecting conductor _20-2 are sometimes collectively called the first connecting conductor 20. _The second connecting conductor _22-1 and the second connecting conductor _22-2 are sometimes collectively called the second connecting conductor 22.

Antenna 1 is configured to be capable of radiating circularly polarized waves. Antenna 1 is configured to exhibit artificial magnetic conductor characters for electromagnetic waves of a predetermined frequency incident on the XY plane of antenna 1 from the positive side of the Z axis. In this disclosure, artificial magnetic conductor characters refer to the characteristics of a surface where the phase difference between the incident wave and the reflected wave is 0 degrees. On a surface that has artificial magnetic conductor characters, the phase difference between the incident wave and the reflected wave is -90 degrees to +90 degrees in the frequency band.

The first conductor 10 is a conductor extending in the XY plane. The XY plane is sometimes called the first surface. The first conductor 10 is configured, for example, in a substantially rectangular shape, but is not limited to this. The width of the first conductor 10 in the Y-axis direction is wider than the widths of the second conductor 12, the third conductor 14, and the fourth conductor 16. The first conductor 10 is disposed, for example, on a plate-shaped metal member 40. The antenna 1 does not necessarily have to include the metal member 40. The metal member 40 is a type of conductive article.

The second conductor 12, the third conductor 14, and the fourth conductor 16 are located away from the first conductor 10 in the Z-axis direction. The second conductor 12, the third conductor 14, and the fourth conductor 16 face the first conductor 10. The second conductor 12, the third conductor 14, and the fourth conductor 16 are sometimes called the upper conductors of the antenna 1. The widths in the Y-axis direction of the second conductor 12, the third conductor 14, and the fourth conductor 16 may be the same. The widths in the X-axis direction of the second conductor 12 and the third conductor 14 may be the same. The width in the X-axis direction of the fourth conductor 16 is wider than the widths in the X-axis direction of the second conductor 12 and the third conductor 14.

The second conductor 12 faces a first end of the first conductor 10 in the X-axis direction. The X-axis direction is also referred to as the first direction. The first end is the end of the first conductor 10 on the negative side of the X-axis. The second conductor 12 is configured, for example, in a substantially rectangular shape, but is not limited to this.

The third conductor 14 faces a second end of the first conductor 10 in the X-axis direction. The second end is the end of the first conductor 10 on the positive side of the X-axis. The third conductor 14 is configured, for example, in a substantially rectangular shape, but is not limited to this. The third conductor 14 is aligned with the second conductor 12 along the X-axis direction.

The fourth conductor 16 is located between the second conductor 12 and the third conductor 14. The fourth conductor 16 is aligned with the second conductor 12 and the third conductor 14 along the X-axis direction. The fourth conductor 16 is not in contact with the second conductor 12 and the third conductor 14. That is, there is a gap between the second conductor 12 and the fourth conductor 16 and between the third conductor 14 and the fourth conductor 16. The fourth conductor 16 faces the first conductor 10 between the second conductor 12 and the third conductor 14. The fourth conductor 16 is configured, for example, in a substantially rectangular shape, but is not limited thereto. A plurality of fourth conductors 16 may be located between the second conductor 12 and the third conductor 14. When a plurality of fourth conductors 16 are located, the respective fourth conductors 16 are not in contact with each other. When a plurality of fourth conductors 16 are located, there is a gap between the respective fourth conductors 16, and they are aligned along the X-axis direction. That is, at least one fourth conductor 16 is located between the second conductor 12 and the third conductor 14 .

The second conductor 12 and the fourth conductor 16 are capacitively connected through a gap. The third conductor 14 and the fourth conductor 16 are capacitively connected through a gap. When multiple fourth conductors 16 are located between the second conductor 12 and the third conductor 14, the respective fourth conductors are capacitively connected to each other through a gap.

The first connecting conductor _20-1 and the first connecting conductor _20-2 are configured to connect the first conductor 10 and the second conductor 12. The first connecting conductor _20-1 and the first connecting conductor _20-2 are, for example, columnar bodies extending in the Z-axis direction. The first connecting conductor _20-1 and the first connecting conductor _20-2 are aligned along the Y-axis direction.

The second connecting conductor _22-1 and the second connecting conductor _22-2 are configured to connect the first conductor 10 and the third conductor 14. The second connecting conductor _22-1 and the second connecting conductor _22-2 are, for example, columnar bodies extending in the Z-axis direction. The second connecting conductor _22-1 and the second connecting conductor _22-2 are aligned along the Y-axis direction.

The power supply conductor 24 is configured to connect the first conductor 10 and the fourth conductor 16. The power supply conductor 24 is, for example, a columnar body extending in the Z-axis direction. The power supply conductor 24 is connected to the power supply point P1 of the first conductor 10. The power supply conductor 24 may be configured to connect the first conductor 10 and the second conductor 12. The power supply conductor 24 may be configured to connect the first conductor 10 and the third conductor 14. As an example of the structure of the antenna 1, the second conductor 12 to the fourth conductor 16 may be written on the same surface of an insulating substrate (not shown). For example, the structure may be such that an insulating substrate is located above the second conductor 12 to the fourth conductor 16 in FIG. 1. Furthermore, the structure may be such that an insulating substrate is also located below the first conductor 10 in FIG. 1.

One end of the coaxial cable 30 is connected to a power feed point P1. The other end of the coaxial cable 30 is connected to an external device (not shown). One end of the coaxial cable 30 is connected to the power feed point P1, for example, by a connector terminal (not shown). The power feed point P1 is sometimes called a connection point.

Depending on the arrangement of the coaxial cable 30, the coaxial cable 30 acts like an antenna, and the antenna characteristics of the antenna 1 change. By arranging the coaxial cable 30 so that it does not act like an antenna, it is desired to stabilize the antenna characteristics of the antenna 1 regardless of the presence or absence of the metal member 40.

Using Figure 4, we will explain how to arrange the coaxial cable so that it does not act like an antenna. Figure 4 is a diagram to explain how to arrange the coaxial cable so that it does not act like an antenna.

Figure 4 shows the first conductor 10. In Figure 4, the X-axis direction is sometimes called the longitudinal direction, and the Y-axis direction is sometimes called the short direction. The power feed point P1 is located at a position L1 in the positive direction of the X-axis from the center O1 of the first conductor 10 in the X-axis direction, and at a position L2 in the negative direction of the Y-axis from the upper side of the first conductor 10. The Y-axis direction is also called the second direction. The power feed point P1 is usually arranged offset from the center of the first conductor 10 for impedance adjustment. The coaxial cable 30 may be extended from the power feed point P1 toward the center of the first conductor 10 and drawn out to the outside of the antenna unit. Specifically, the coaxial cable 30 may be drawn out from the upper side of the first conductor 10 within the range of the distance L1. The coaxial cable 30 may be drawn out from the lower side of the first conductor 10 within the range of the distance L1.

By drawing out the coaxial cable 30 from the range between the center O1 of the first conductor 10 and the power feed point P1 in the X-axis direction, the direction of the current I1 flowing through the antenna 1 and the direction of the current I10 flowing through the coaxial cable 30 are opposite to each other. Here, it is preferable that the coaxial cable 30 is not extended from the position of the power feed point P1 in the positive direction of the Y-axis and drawn out to the outside of the antenna unit. As shown in FIG. 4, the current I1 flows on the positive side of the X-axis, and the current I10 flows on the negative side of the X-axis. In the example shown in FIG. 4, the coaxial cable 30 is drawn out to the outside of the antenna unit from a position P11. Although not clear in FIG. 4, the position P11 may be a position where the upper sides of the upper conductor and the lower conductor spatially overlap. The coaxial cable 30 may be fixed at the position P11 with a fastener or resin that prevents misalignment. The direction of the electric field radiated by the antenna 1 is opposite on the positive side and the negative side of the X-axis from the center O1. Therefore, the direction of the electric field radiated by antenna 1 is the same at position P11 and at feed point P1. Therefore, the direction of the magnetic field generated by antenna 1 is opposite to the direction of the magnetic field generated by coaxial cable 30. In other words, the magnetic field of antenna 1 weakens the magnetic field generated by coaxial cable 30. As the magnetic field from coaxial cable 30 is weakened, it becomes difficult for coaxial cable 30 to function as an antenna.

The coaxial cable 30 should be arranged at a longer distance from the power feed point P1 in the longitudinal direction of the first conductor 10. Specifically, in the example shown in FIG. 4, the coaxial cable 30 should be arranged at a longer distance than the distance L3 from the power feed point P1 to one short side and the distance L4 to the other short side. In the example shown in FIG. 4, the coaxial cable 30 should be pulled out from the distance L3 side. Specifically, the coaxial cable 30 should be pulled out to the outside of the antenna unit so that the distance over which the coaxial cable 30 and the first conductor 10 overlap is longer.

In this embodiment, the power supply point P1 is arranged to be shifted from the center of the first conductor 10 in the longitudinal direction (positive direction of the X-axis) and the lateral direction (negative direction of the Y-axis). The coaxial cable 30 may be drawn from the upper side or the lower side of the first conductor 10 as long as it is within the range of the distance L1. The coaxial cable 30 may be arranged on the longer side from the power supply point P1 in the lateral direction of the first conductor 10. Specifically, in the example shown in FIG. 4, the distance L2 from the power supply point P1 to one long side is compared with the distance L5 to the other long side, and the coaxial cable 30 may be arranged on the longer side. In the example shown in FIG. 4, the coaxial cable 30 may be drawn from the distance L2 side, that is, the upper side of the first conductor 10. Specifically, the coaxial cable 30 may be drawn to the outside of the antenna unit so that the distance over which the coaxial cable 30 and the first conductor 10 overlap is long.

Figure 5 is a diagram for explaining a method of arranging the coaxial cable 30 outside the first conductor 10. After being pulled out to the outside of the antenna unit, the coaxial cable 30 may face in a direction different from the direction in which it extends inside the antenna unit. As shown in Figure 5, the coaxial cable 30 may be bent in a direction along the Y-axis after being pulled out from position P11, for example. The coaxial cable 30 is not limited to the example shown in Figure 5, and after being pulled out from position P11, it may be bent in any direction according to the design.

The coaxial cable 30 may be arranged to act like an antenna. When the antenna 1 is used only in free space, the antenna efficiency can be improved. In this embodiment, use of the antenna 1 in free space may mean use without the metal member 40.

Using Figures 6 and 7, we will explain a method of arranging a coaxial cable to make it act like an antenna. Figures 6 and 7 are diagrams for explaining a method of arranging a coaxial cable to make it act like an antenna.

[First method]
6 shows the first conductor 10. When the coaxial cable 30 is used as an antenna, it is preferable to extend the coaxial cable 30 in a direction opposite to the direction toward the center O1 and pull it out from the antenna portion. For example, it is preferable to pull the coaxial cable 30 from a position P21 on the upper side of the first conductor 10 within a range of a distance L4.

By drawing out the coaxial cable 30 from the upper side of the first conductor 10 within the range of distance L4, the direction of the current I1 flowing through the antenna 1 and the direction of the current I20 flowing through the coaxial cable 30 become the same. As shown in FIG. 6, the current I1 flows on the positive side of the X-axis, and the current I20 flows on the positive side of the X-axis. Since the position P21 and the power feed point P1 are both located on the positive side of the center O1, the direction of the electric field radiated by the antenna 1 becomes the same at the position P21 and the power feed point P1. In the example shown in FIG. 6, the direction of the magnetic field generated from the antenna 1 becomes the same as the direction of the magnetic field generated from the coaxial cable 30. In this case, the magnetic field of the antenna 1 does not weaken the magnetic field of the coaxial cable 30. In other words, the coaxial cable 30 behaves as an antenna.

[Second Method]
7 shows the first conductor 10. When the coaxial cable 30 is used as an antenna, it is preferable to extend the coaxial cable 30 beyond the center O1 and pull it out from the antenna portion. For example, it is preferable to pull the coaxial cable 30 from a position P31 on the upper side of the first conductor 10 within a range of a distance L6.

By pulling out the coaxial cable 30 from within the range of distance L6, the direction of the current I1 flowing through the antenna 1 and the direction of the current I30 flowing through the coaxial cable 30 become opposite. As shown in FIG. 7, the current I1 flows on the positive side of the X-axis, and the current I30 flows on the negative side of the X-axis. The direction of the electric field radiated by the antenna 1 is opposite on the positive side and the negative side of the X-axis from the center O1. Therefore, in the example shown in FIG. 7, the direction of the magnetic field generated from the coaxial cable 30 is opposite to the direction of the magnetic field generated from the antenna 1 in the part located within the range of distance L1, and is the same as the direction of the magnetic field generated from the antenna 1 in the part located within the range of distance L6. Therefore, the part of the coaxial cable 30 located within the range of distance L1 does not easily behave as an antenna, but the part located within the range of distance L behaves as an antenna. As a result, the coaxial cable 30 behaves as an antenna.

[simulation]
A model for simulating the antenna radiation characteristics of the antenna according to the embodiment will be described with reference to Fig. 8A, Fig. 8B, and Fig. 8C. Fig. 8A to Fig. 8C are diagrams for explaining the antenna model according to the embodiment.

As shown in FIG. 8A , the antenna model 100 includes a first conductor model 102, a second conductor model 104, a third conductor model 106, a fourth conductor model 108, first connecting conductor models 110 ₁ and 110 ₂ , second connecting conductor models 112 ₁ and 112 ₂ , a feed conductor model 114, a connector model 116, and a coaxial cable model 118.

The antenna model 100 is a model corresponding to the antenna 1. The first conductor model 102 corresponds to the first conductor 10. The second conductor model 104 corresponds to the second conductor 12. The third conductor model 106 corresponds to the third conductor 14. The fourth conductor model 108 corresponds to the fourth conductor 16. The first connecting conductor models _110-1 and _110-2 correspond to the first connecting conductors _20-1 and _20-2 , respectively. The second connecting conductor models _112-1 and _112-2 correspond to the second connecting conductors _22-1 and _22-2 , respectively. The power supply conductor model 114 corresponds to the power supply conductor 24. That is, the first conductor model 102, the second conductor model 104, the third conductor model 106, the fourth conductor model 108, the first connecting conductor models _110-1 and _110-2 , the second connecting conductor models _112-1 and _112-2 , and the power supply conductor model 114 may be antenna unit models corresponding to the antenna unit.

8A, in the antenna model 100, the coaxial cable model 118 is pulled out to the outside of the antenna part model within a range of a distance L10 between the center O10 of the first conductor model 102 and the power supply conductor model 114. In other words, the antenna model 100 is a model in which the coaxial cable 30 of the antenna 1 is arranged so as not to act as an antenna.

8B, in the antenna model 100A, the coaxial cable model 118 is pulled out to the outside of the antenna part model within a range of a distance L20 between the center O10 of the first conductor model 102 and the left end of the first conductor model 102. In other words, the antenna model 100A is a model in which the coaxial cable 30 of the antenna 1 is arranged to act like an antenna.

8C, in antenna model 100B, coaxial cable model 118 is pulled out to the outside of the antenna part model within a distance L30 between power supply conductor model 114 and the right end of first conductor model 102. In other words, antenna model 100B is a model in which coaxial cable 30 of antenna 1 is arranged to act like an antenna.

Figure 9 is a graph to explain the simulation results of antenna radiation efficiency in free space. In Figure 9, the horizontal axis shows frequency [MHz] and the vertical axis shows antenna radiation efficiency [dB].

Figure 9 shows graphs G1, G2, and G3. Graph G1 shows the simulation results of the antenna radiation efficiency in free space of the antenna model 100 shown in Figure 8A. Graph G2 shows the simulation results of the antenna radiation efficiency in free space of the antenna model 100A shown in Figure 8B. Graph G3 shows the simulation results of the antenna radiation efficiency in free space of the antenna model 100B shown in Figure 8C.

As shown in graph G1, in antenna model 100, no magnetic field is generated around coaxial cable model 118. The antenna radiation efficiency of antenna model 100 in the frequency band from 750 MHz to 950 MHz is approximately -13 dB to -3 dB.

As shown in graph G2, in antenna model 100A, a magnetic field is generated around coaxial cable model 118. The antenna radiation efficiency of antenna model 100A in the frequency band from 750 MHz to 950 MHz is approximately -7 dB to -1.5 dB. In other words, antenna model 100A has improved antenna radiation efficiency compared to antenna model 100.

As shown in graph G3, in antenna model 100B, a magnetic field is generated around coaxial cable model 118. The antenna radiation efficiency of antenna model 100B in the frequency band from 750 MHz to 950 MHz is approximately -9 dB to -1 dB. In other words, antenna model 100B has improved antenna radiation efficiency compared to antenna model 100.

Figure 10 is a graph for explaining the results of a simulation of the antenna radiation efficiency on a metal. Specifically, Figure 10 shows the results of a simulation of the antenna radiation efficiency when the first conductor model 102 shown in Figures 8A to 8C is placed on a metal (not shown). In Figure 10, the horizontal axis indicates frequency [MHz], and the vertical axis indicates antenna radiation efficiency [dB].

Figure 10 shows graphs G11, G12, and G13. Graph G11 shows the simulation results of the antenna radiation efficiency on a metal of the antenna model 100 shown in Figure 8A. Graph G2 shows the simulation results of the antenna radiation efficiency on a metal of the antenna model 100A shown in Figure 8B. Graph G3 shows the simulation results of the antenna radiation efficiency on a metal of the antenna model 100B shown in Figure 8C.

As shown in Figure 10, graphs G11, G12, and G13 are almost identical in the frequency band from 750 MHz to 950 MHz. The antenna radiation efficiency in the frequency band from 750 MHz to 950 MHz for antenna models 100 to 100B is approximately -12 dB to -2.5 dB. As shown in graphs G12 and G13, for antenna models 100A and 100B, no magnetic field is generated around coaxial cable model 118 on metal, and the antenna radiation efficiency is not improved.

That is, in this embodiment, when the coaxial cable 30 is arranged so that it does not act like an antenna, there is no change in the characteristics of the antenna 1 when it is used in free space and when it is set on a metal. In other words, by arranging the coaxial cable 30 so that it does not act like an antenna, the characteristics of the antenna 1 can be stabilized.

In addition, in this embodiment, the coaxial cable 30 is arranged to act like an antenna, which can improve the efficiency of the antenna 1 when used in free space. In other words, by arranging the coaxial cable 30 to act like an antenna, the antenna 1 can be configured as an antenna with high antenna radiation efficiency in free space.

In addition, in this embodiment, the coaxial cable 30 may be positioned so that it does not act as an antenna, or so that it does act as an antenna, depending on the purpose of use.

Next, we will explain the change in antenna radiation efficiency in free space due to differences in the angle with respect to the X-axis at the position of the feed point P1 of the coaxial cable 30. Figure 11 is a diagram for explaining the angle at the position of the feed point P1 of the coaxial cable. As shown in Figure 11, the angle on the positive side of the Y-axis is 0°, the angle on the negative side of the X-axis is 90°, the angle on the negative side of the Y-axis is 180°, and the angle on the positive side of the X-axis is 270°.

Figure 12 is a graph to explain the simulation results of the antenna radiation efficiency depending on the angle at which the coaxial cable is pulled out from the antenna unit in free space. In Figure 12, the horizontal axis shows frequency [MHz], and the vertical axis shows antenna radiation efficiency [dB].

Figure 12 shows graphs G21, G22, G23, G24, G25, and G26. Graph G21 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 80°. Graph G22 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 70°. Graph G23 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 50°. Graph G24 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30°. Graph G25 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 0°. Graph G26 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 330°. Specifically, graphs G21 and G22 show the simulation results of the antenna radiation efficiency when the coaxial cable 30 is led out from the antenna unit within a range of distance L6 in the example shown in Fig. 7. Graphs G23 and G24 show the simulation results of the antenna radiation efficiency when the coaxial cable 30 is led out from the antenna unit within a range of distance L1 in the example shown in Fig. 4. Graph G26 shows the simulation results of the antenna radiation efficiency when the coaxial cable 30 is led out from the antenna unit within a range of distance L3 in the example shown in Fig. 6.

As shown in Figure 12, when the angle at which the coaxial cable 30 is pulled out from the antenna section is 50° and 30°, the antenna radiation efficiency is relatively low. In this case, the magnetic field generated by the coaxial cable 30 is weak, meaning that the coaxial cable 30 does not function as an antenna.

As shown in Figure 12, when the angle at which the coaxial cable 30 is pulled out from the antenna section is 80°, 70°, 0°, or 330°, the antenna radiation efficiency is relatively high. In this case, the magnetic field generated by the coaxial cable 30 is strong, which means that the coaxial cable 30 acts as an antenna.

Figure 13 is a graph to explain the simulation results of the antenna radiation efficiency depending on the angle at which the coaxial cable is pulled out from the antenna unit in free space. In Figure 13, the horizontal axis shows frequency [MHz], and the vertical axis shows antenna radiation efficiency [dB].

Figure 13 shows graphs G31, G32, G33, G34, G35, and G36. Graph G31 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 0°. Graph G32 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 330°. Graph G33 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30°. Graph G34 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 180°. Graph G35 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 210°. Graph G36 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 150°.

When the angle at which the coaxial cable 30 is pulled out from the antenna unit is 0° and when it is 180°, the coaxial cable 30 is line-symmetrical with respect to the X-axis. When the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30° and when it is 150°, the coaxial cable 30 is line-symmetrical with respect to the X-axis. When the angle at which the coaxial cable 30 is pulled out from the antenna unit is 210° and when it is 330°, the coaxial cable 30 is line-symmetrical with respect to the X-axis.

As shown in graphs G31, G32, G34, and G35, when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 0°, 180°, 210°, and 330°, the antenna radiation efficiency is relatively high. In this case, the magnetic field generated by the coaxial cable 30 is strong, which means that the coaxial cable 30 acts as an antenna.

As shown in graphs G33 and G36, when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30° and 150°, the antenna radiation efficiency is relatively low. Comparing graphs G33 and G36, the antenna radiation efficiency is higher when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 150° than when it is 30°. This is because when the angle of the feed point P1 of the coaxial cable 30 is 30°, the distance over which the coaxial cable 30 overlaps with the first conductor 10 and the fourth conductor 16 when pulled out from the antenna unit is longer than when it is 150°. The longer the distance over which the coaxial cable 30 overlaps with the first conductor 10 and the fourth conductor 16 when pulled out from the antenna unit, the more the coaxial cable 30 can be suppressed from acting as an antenna.

Next, we will explain the change in antenna radiation efficiency when the coaxial cable 30 is bent after being pulled out from the antenna unit in free space. Figure 14 is a diagram showing an antenna model in which the coaxial cable 30 is bent after being pulled out from the antenna unit. As shown in antenna model 100C, the change in antenna radiation efficiency was analyzed when the coaxial cable model 118 is bent along the Y axis from a position where the first conductor model 102 and the upper side of the fourth conductor model 108 spatially overlap when being pulled out from the antenna unit model.

Figure 15 is a graph to explain the change in antenna radiation efficiency when the coaxial cable is bent when it is pulled out from the antenna section in free space. In Figure 15, the horizontal axis shows frequency [MHz] and the vertical axis shows antenna radiation efficiency [dB].

Figure 15 shows graphs G41, G42, G43, and G44. Graph G41 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 70°. Graph G42 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30°. Graph G43 shows the simulation result of the antenna radiation efficiency when the angle at the feed point P1 of the coaxial cable 30 is 70° and the coaxial cable 30 is bent in the direction of 0° when pulled out from the antenna unit. Graph G44 shows the simulation result of the antenna radiation efficiency when the angle at which the coaxial cable 30 is pulled out from the antenna unit is 30° and the coaxial cable 30 is bent in the direction of 0° when pulled out from the antenna unit.

Comparing graph G41 and graph G43, when the angle at which the coaxial cable 30 is pulled out from the antenna section is 70°, it can be said that there is no difference in the antenna radiation efficiency between when the coaxial cable 30 is bent and when it is not bent.

Comparing graph G42 and graph G44, when the angle at which the coaxial cable 30 is pulled out from the antenna section is 30°, it can be said that there is no difference in the antenna radiation efficiency between when the coaxial cable 30 is bent and when it is not bent.

In this embodiment, after the coaxial cable 30 is pulled out from the antenna section, it may be bent freely.

[Wireless communication device]
The wireless communication device according to this embodiment will be described with reference to Fig. 16. Fig. 16 is a block diagram showing an example of the configuration of the wireless communication device according to this embodiment.

16, the wireless communication device 200 includes at least an antenna 1 and a controller 3. The wireless communication device 200 may further include a memory 2, a sensor 4, and a battery 5.

Memory 2 may include, for example, a semiconductor memory. Memory 2 may be configured to function as a work memory for controller 3. Memory 2 may be included in controller 3. Memory 2 stores a program describing the processing contents for realizing each function of wireless communication device 200, information used by wireless communication device 200, and the like.

The controller 3 may include, for example, a processor. The controller 3 may include one or more processors. The processor may include a general-purpose processor that loads a specific program to execute a specific function, and a dedicated processor specialized for a specific process. The dedicated processor may include an IC for a specific application. The IC for a specific application is also called an ASIC (Application Specific Integrated Circuit). The processor may include a programmable logic device. The programmable logic device is also called a PLD (Programmable Logic Device). The PLD may include an FPGA (Field-Programmable Gate Array). The controller 3 may be either a SoC (System-on-a-Chip) in which one or more processors work together, or a SiP (System in a Package). The controller 3 may store various information or programs for operating each component of the wireless communication device 200 in the memory 2.

The controller 3 may be configured to generate a transmission signal to be transmitted from the wireless communication device 200. The controller 3 may be configured to acquire measurement data from the sensor 4, for example. The controller 3 may be configured to generate a transmission signal according to the measurement data. The controller 3 may be configured to transmit a baseband signal to the antenna 1.

The sensor 4 includes various sensors. The sensor 4 may include, for example, a speed sensor, a vibration sensor, an acceleration sensor, a gyro sensor, a rotation angle sensor, an angular velocity sensor, a geomagnetic sensor, a magnet sensor, a temperature sensor, a humidity sensor, an air pressure sensor, a light sensor, an illuminance sensor, a UV sensor, a gas sensor, a gas concentration sensor, an atmosphere sensor, a level sensor, an odor sensor, a pressure sensor, an air pressure sensor, a contact sensor, a wind sensor, an infrared sensor, a human presence sensor, a displacement sensor, an image sensor, a weight sensor, a smoke sensor, a liquid leakage sensor, a vital sensor, a battery remaining amount sensor, and an ultrasonic sensor. The sensor 4 may include a GNSS (Global Navigation Satellite System) sensor that acquires the current position information of the wireless communication device 200.

The battery 5 may be configured to supply power to the wireless communication device 200. The battery 5 may be configured to supply power to at least one of the memory 2, the controller 3, and the sensor 4. The battery 5 may include at least one of a primary battery and a secondary battery. The negative electrode of the battery 5 may be configured to be electrically connected to a ground terminal of a circuit board (not shown).

Although the embodiments of the present invention have been described above, the present invention is not limited to the contents of these embodiments. Furthermore, the components described above include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components described above can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the components can be made without departing from the spirit of the embodiments described above.

REFERENCE SIGNS LIST 1 Antenna 10 First conductor 12 Second conductor 14 Third conductor 16 Fourth conductor 20 First connecting conductor 22 Second connecting conductor 24 Power supply conductor 30 Coaxial cable 40 Metal member 100, 100A, 100B, 100C Antenna model 102 First conductor model 104 Second conductor model 106 Third conductor model 108 Fourth conductor model 110 ₁ , 110 ₂ First connecting conductor model 112 ₁ , 112 ₂ Second connecting conductor model 114 Power supply conductor model 116 Connector model 200 Wireless communication device

Claims (5)

An antenna portion;
a coaxial cable having one end connected to the antenna unit and the other end connected to an external device;
Including,
The antenna unit includes:
A first conductor extending in a first surface direction;
a second conductor extending in the first plane direction and connected to a first end of the first conductor in a first direction;
a third conductor that faces a second end of the first conductor in the first direction, is connected to the first conductor, and extends in the first plane direction aligned with the second conductor in the first direction;
At least one fourth conductor extending in the first surface direction between the second conductor and the third conductor and spaced apart from the second conductor and the third conductor in the first direction;
Equipped with
the coaxial cable is connected to a connection point located at a position shifted in the first direction from the center of the antenna unit in the first direction, extends in the first surface direction toward the center in the first direction, and is drawn out to the outside of the antenna unit from between the center in the first direction and the connection point.
antenna. An antenna portion;
a coaxial cable having one end connected to the antenna unit and the other end connected to an external device;
Including,
The antenna unit includes:
A first conductor extending in a first surface direction;
a second conductor extending in the first plane direction and connected to a first end of the first conductor in a first direction;
a third conductor that faces a second end of the first conductor in the first direction, is connected to the first conductor, and extends in the first plane direction aligned with the second conductor in the first direction;
At least one fourth conductor extending in the first surface direction between the second conductor and the third conductor and spaced apart from the second conductor and the third conductor in the first direction;
Equipped with
the coaxial cable is connected to a connection point located at a position offset in the first direction from the center of the antenna unit in the first direction, and extends in the first surface direction in a direction opposite to the direction toward the center of the first direction and is pulled out to the outside of the antenna unit from a position in the direction opposite to the center of the first direction or a position in the direction toward the center of the first direction and beyond the center of the first direction.
antenna. the connection point is located in a position shifted in a second direction perpendicular to the first direction from a center of the antenna part in the second direction,
The coaxial cable extends in a direction toward the center in the second direction and is drawn out to the outside of the antenna unit.
3. An antenna as claimed in claim 1 or 2. a conductive article connected to the first conductor;
3. An antenna as claimed in claim 1 or 2 . An antenna according to claim 1 or 2 ;
A controller that controls the antenna to communicate with an external electronic device;
A wireless communication device comprising:

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