Antenna equipment

Abstract

An antenna device according to the present invention includes: a grounding part; and an antenna that is provided at an end of the grounding part, that includes a power supply section and a first element extending from the power supply section, and that corresponds to at least a first frequency band. The grounding part includes an arm section defined by an outer edge of the grounding part and a slit having an open end located on the outer edge and a closed end located inside the grounding part. The power supply section is provided on the arm section.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses an antenna device including a telephone antenna element provided on the same ground as a GPS / VICS antenna element.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, for example, when miniaturizing an antenna device, it may be difficult to secure the length of an antenna element corresponding to a low-frequency band radio wave.

[0005] An example of an object of the present invention is to easily realize an antenna corresponding to a low-frequency band radio wave. Other objects of the present invention will become apparent from the description herein.

Means for Solving the Problems

[0006] One aspect of the present invention is an antenna device having a ground portion, a feeding portion provided at an end of the ground portion, a first element extending from the feeding portion, and an antenna corresponding to at least a first frequency band, the ground portion having an open end at an outer edge thereof and a slit having a closed end formed inside the ground portion, the ground portion having an arm portion defined by the outer edge of the ground portion, the open end located at the outer edge, and the slit having a closed end located inside the ground portion, and the feeding portion being provided on the arm portion.

[0007] According to the above embodiment of the present invention, an antenna that responds to low-frequency radio waves can be easily realized. [Brief explanation of the drawing]

[0008] [Figure 1] This is a perspective view of the antenna device 100. [Figure 2] This is an exploded perspective view of the antenna device 100. [Figure 3] This is a perspective view showing the antenna device 100 with the holder 20 and patch antenna 60 removed. [Figure 4] This is a plan view showing the antenna device 100 with the holder 20 and patch antenna 60 removed. [Figure 5] This is a plan view of the ground section 10 on which the circuit board 80 is provided. [Figure 6A] This is a magnified plan view of the area around the substrate 80 of the ground section 10. [Figure 6B] This is an explanatory diagram of filter 81 as a band-stop filter. [Figure 7A] This is a diagram illustrating the antenna device 100. [Figure 7B] This is a diagram illustrating the antenna device 100X. [Figure 7C] This is a diagram illustrating antenna device 100Y. [Figure 8] This graph shows an example of the frequency characteristics of antenna devices 100, 100X, and 100Y. [Figure 9A] This diagram illustrates a first modified example of the arm portion 11 and slit 70 of the ground portion 10. [Figure 9B] This diagram illustrates a second modified example of the arm portion 11 and slit 70 of the ground portion 10. [Figure 9C] This diagram illustrates a third modified example of the arm portion 11 and slit 70 of the ground portion 10. [Modes for carrying out the invention]

[0009] From the descriptions in this specification and the attached drawings, at least the following matters will become clear.

[0010] Hereinafter, preferred embodiments of the present invention will be described while referring to the drawings. The same or equivalent components, members, etc. shown in each drawing are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate.

[0011] ==Antenna Device 100== <<Overview>> First, while referring to FIGS. 1 to 4, an overview of the configuration of the antenna device 100 will be described.

[0012] FIG. 1 is a perspective view of the antenna device 100. FIG. 2 is an exploded perspective view of the antenna device 100. FIG. 3 is a perspective view showing a state where the holder 20 and the patch antenna 60 are removed from the antenna device 100. FIG. 4 is a plan view showing a state where the holder 20 and the patch antenna 60 are removed from the antenna device 100. In FIGS. 3 and 4, in order to simply illustrate the ground portion 10, the TEL antenna 30 (first antenna), and the TEL antenna 50 (second antenna) (all of which will be described later), which are part of the configuration of the antenna device 100, the holder 20 and the patch antenna 60 are removed from the antenna device 100.

[0013] In FIG. 1, the direction in which the TEL antenna 30 and the patch antenna 60 are arranged is defined as the X direction. Also, the side from the TEL antenna 30 toward the patch antenna 60 is defined as the +X direction, and the opposite side (the side from the patch antenna 60 toward the TEL antenna 30) is defined as the -X direction.

[0014] Also, in FIG. 1, the direction in which the TEL antenna 50 and the patch antenna 60 are arranged is defined as the Y direction. Also, the side from the TEL antenna 50 toward the patch antenna 60 is defined as the +Y direction, and the opposite side (the side from the patch antenna 60 toward the TEL antenna 50) is defined as the -Y direction.

[0015] Also, in FIG. 1, the direction perpendicular to the X direction and the Y direction is defined as the Z direction. Also, the side from the ground portion 10 toward the patch antenna 60 is defined as the +Z direction, and the opposite side (the side from the patch antenna 60 toward the ground portion 10) is defined as the -Z direction.

[0016] The antenna device 100 is an in-vehicle antenna device used in a vehicle (not shown). In the present embodiment, the antenna device 100 is housed in a case (not shown) and is mounted, for example, inside the roof or the instrument panel of the vehicle. However, the antenna device 100 may be mounted on a part of the vehicle other than inside the roof or the instrument panel. Also, the antenna device 100 may be an antenna device other than for in-vehicle use.

[0017] The antenna device 100 includes a ground portion 10, a holder 20, a TEL antenna 30, a TEL antenna 50, and a patch antenna 60.

[0018] The ground portion 10 is a member that functions as the ground of the antennas included in the antenna device 100. In the present embodiment, the ground portion 10 functions as a common ground for the TEL antenna 30, the TEL antenna 50, and the patch antenna 60. However, the ground portion 10 may function as a common ground for some of the antennas included in the antenna device 100. For example, the ground portion 10 may function as a common ground for the TEL antenna 30 and the TEL antenna 50, and another ground portion may function as the ground for the patch antenna 60.

[0019] Also, as shown in FIGS. 1 and 2, the ground portion 10 of the present embodiment is formed as an integral metal plate (sheet metal) on which the TEL antenna 30, the TEL antenna 50, and the patch antenna 60 are provided. Also, a slit 70 described later is formed in the ground portion 10. However, the ground portion 10 may be composed of a plurality of separate metal plates. For example, the ground portion 10 may be configured such that a metal plate on which the TEL antenna 30 and the TEL antenna 50 are provided and another metal plate on which the patch antenna 60 is provided are electrically connected.

[0020] Furthermore, the ground section 10 may be formed in a shape other than a plate, as long as it functions as the ground for the antenna of the antenna device 100. Also, the ground section 10 may be constructed by freely combining metal and non-metallic materials, as long as it functions as the ground for the antenna of the antenna device 100. For example, the ground section 10 may consist of a metal plate and a resin insulator. Alternatively, the ground section 10 may be composed of a single printed circuit board (PCB) on which a conductor pattern is formed.

[0021] Furthermore, in this embodiment, as shown in Figures 3 and 4, a substrate 80 (first substrate) to which the TEL antenna 30 is connected and a substrate 90 (second substrate) to which the TEL antenna 50 is connected are provided on a ground portion 10 made of a metal plate. Substrates 80 and 90 are printed circuit boards, and conductive patterns are formed on the surface of the printed circuit boards.

[0022] Furthermore, as shown in Figure 4, the ground portion 10 is formed in a roughly quadrilateral shape in a plan view when viewed in the Z direction. In the following description, "roughly quadrilateral" refers to a shape consisting of four sides, including, for example, a square or a rectangle, and may, for example, have at least some corners cut diagonally to the sides, or may have at least some corners that include curves.

[0023] In the "approximately quadrilateral" shape described above, notches (recesses) or protrusions (convex parts) may be provided on some of the sides. In this embodiment, for example, as shown in Figures 2 and 3, the ground portion 10 has notches 19A to 19C formed by being cut out from the main body portion of the ground portion 10. In addition, the ground portion 10 in this embodiment has, for example, a ground-side element 16 that protrudes from the main body portion of the ground portion 10. Furthermore, the ground portion 10 may be a polygon other than an approximately quadrilateral, or it may be a circle or an ellipse.

[0024] Further details regarding the configuration of the ground section 10, including the notches 19A to 19C and the ground-side element 16, will be described later.

[0025] The holder 20, as shown in Figures 1 and 2, is a component that holds the TEL antenna 30, TEL antenna 50, and patch antenna 60, and is provided on the ground portion 10. The holder 20 is made of, for example, resin. However, the holder 20 may be made of a material other than resin, as long as it can hold the TEL antenna 30, TEL antenna 50, and patch antenna 60. The holder 20 may also hold components other than the TEL antenna 30, TEL antenna 50, and patch antenna 60. Note that the antenna device 100 does not need to have the holder 20 if the TEL antenna 30, TEL antenna 50, and patch antenna 60 are held in a case not shown.

[0026] The TEL antenna 30 is a broadband antenna based on a monopole antenna for mobile communications. The TEL antenna 30 of this embodiment supports radio waves in the 614MHz to 5100MHz (5.1GHz) band for GSM, UMTS, LTE, and 5G. However, the TEL antenna 30 is not limited to this and may support radio waves in some frequency bands of GSM, UMTS, LTE, and 5G (for example, only for 5G). Furthermore, the TEL antenna 30 may support radio waves in frequency bands for telematics, and may support radio waves in frequency bands other than those for GSM, UMTS, LTE, and 5G. In the following description, the TEL antenna 30 may be simply referred to as "antenna".

[0027] In the following description, a predetermined low-frequency band within the frequency band of radio waves that the TEL antenna 30 or the TEL antenna 50 (described later) corresponds to may be referred to as the "low frequency band." In this embodiment, the low frequency band refers to, for example, the 614MHz to 960MHz band. Furthermore, a predetermined frequency band higher than the low frequency band may be referred to as the "mid- and high frequency band." In this embodiment, the mid- and high frequency band refers to, for example, both the 1710MHz to 2690MHz band (mid frequency band) and the 3300MHz to 5100MHz band (high frequency band). However, the examples of "low frequency band" and "mid- and high frequency band" are not limited to these and may differ depending on the frequency band of radio waves that the TEL antenna 30 or the TEL antenna 50 corresponds to. In the following description, the low frequency band may be referred to as the "first frequency band," and the mid- and high frequency band as the "second frequency band."

[0028] The TEL antenna 30 is provided at the end of the ground section 10, as shown in Figures 1 to 4. Specifically, the TEL antenna 30 is provided at the end of the ground section 10 on the -X side. However, the location of the ground section 10 on which the TEL antenna 30 is provided is not limited to the -X side end, but may be any end of the ground section 10, for example, the +X side end.

[0029] In this embodiment, the TEL antenna 30 is formed from a single metal plate (sheet metal). However, the TEL antenna 30 does not have to be formed from a single metal plate; for example, it may be constructed by combining a metal component and a non-metal component, or by physically or electrically connecting multiple metal components. Furthermore, the TEL antenna 30 may be formed from a conductive pattern provided on a printed circuit board.

[0030] As shown in Figures 1 to 3, the TEL antenna 30 has a feed point 31 and a first element 32 extending from the feed point 31 in the +Z direction.

[0031] The feed point 31 is the region that includes the feed point of the TEL antenna 30. In this embodiment, the feed point 31 is located in the ground section 10 (specifically, the arm section 11, which will be described later).

[0032] The first element 32 is an element used in the frequency band of the corresponding radio waves of the TEL antenna 30. As shown in Figures 1 to 3, the first element 32 has a first part 33, a second part 34, and a third part 35.

[0033] The first part 33 is the portion (element) of the TEL antenna 30 used in the low-frequency band of the corresponding radio wave frequency band. Therefore, the first part 33 is formed to have a length and width corresponding to the wavelength used in the low-frequency band (for example, the wavelength at 699 MHz). In this embodiment, the first part 33 extends opposite the ground portion 10, as shown in Figures 1 to 3. Note that the direction in which the first part 33 extends is not limited to being parallel or substantially parallel to the ground portion 10, but may also be inclined at a predetermined angle with respect to the ground portion 10. Furthermore, the first part 33 may be provided to extend in the +Z direction with respect to the ground portion 10.

[0034] The second part 34 is the portion (element) of the TEL antenna 30 used in the medium- and high-frequency bands of the corresponding radio wave frequency band. In this embodiment, the second part 34 is used in the frequency band corresponding to the harmonic components of the corresponding frequency of the first part 33 (for example, around 2 GHz). Therefore, the second part 34 is formed to have a length and width corresponding to the wavelength used in the frequency band corresponding to the harmonic components of the corresponding frequency of the first part 33. Because the first element 32 has the second part 34, the bandwidth of the radio wave frequency band (especially the medium- and high-frequency bands) that the TEL antenna 30 supports can be extended.

[0035] Furthermore, in this embodiment, the second portion 34 extends opposite the ground portion 10, as shown in Figures 1 to 3. Note that the direction in which the second portion 34 extends is not limited to being parallel or substantially parallel to the ground portion 10, but may also be inclined at a predetermined angle with respect to the ground portion 10. Additionally, the second portion 34 may be provided to extend in the +Z direction relative to the ground portion 10.

[0036] The third part 35 is an element of the TEL antenna 30 used in at least the medium- and high-frequency bands of the corresponding radio wave frequency bands. In this embodiment, the third part 35 is provided to improve the characteristics of the TEL antenna 30, particularly in the high-frequency bands (for example, around 5 GHz) of the medium- and high-frequency bands. For this reason, the third part 35 is formed to have a length and width corresponding to the wavelength used in the high-frequency bands of the medium- and high-frequency bands.

[0037] Furthermore, in this embodiment, the third portion 35 extends toward the ground portion 10, as shown in Figures 1 to 3. In other words, the third portion 35 is the part of the TEL antenna 30 that extends in the Z direction. The first portion 33 and the second portion 34 extend from the third portion 35 in the X direction, respectively. Note that the direction in which the third portion 35 extends is not limited to being perpendicular to the ground portion 10, but may also be inclined at a predetermined angle relative to the ground portion 10. Moreover, the third portion 35 may extend opposite to the ground portion 10. Similarly, the first portion 33 and the second portion 34 may extend from the third portion 35 opposite to the ground portion 10, or they may extend in the same direction as the third portion 35, or they may extend inclined at a predetermined angle relative to the ground portion 10.

[0038] In this embodiment, the first element 32 of the TEL antenna 30 has a first portion 33, a second portion 34, and a third portion 35, so that the lengths of the elements of the TEL antenna 30 are all different. This allows the TEL antenna 30 to correspond to different frequency bands. Therefore, the TEL antenna 30 can correspond to radio waves in a wide frequency band. In other words, the TEL antenna 30 can correspond to radio waves in a broadband frequency band that includes low frequency bands and medium and high frequency bands. Therefore, an antenna that corresponds to radio waves in a broadband frequency band by being provided such that, for example, the element has a first portion 33, a second portion 34, and a third portion 35, as in the TEL antenna 30 of this embodiment, is sometimes referred to as a "broadband antenna based on a monopole antenna".

[0039] As described above, the TEL antenna 30 is formed from a single metal plate (sheet metal). Specifically, as shown in Figures 1 to 3, the TEL antenna 30 is formed from a single metal plate with a third portion 35 and a first portion 33 and a second portion 34 bent from the third portion 35. However, the TEL antenna 30 may also be composed of separate metal members, for example, the first portion 33, the second portion 34, and the third portion 35, which may be electrically connected.

[0040] The shape of the first element 32 is not limited to those shown in Figures 1 to 4. For example, the first element 32 may not have a third part 35 and may consist of a first part 33 and a second part 34. Also, the first part 33 and the second part 34 do not have to be shaped as branches of the third part 35. For example, the first part 33, the second part 34, and the third part 35 may each branch (extend) from other parts of the first element 32. Furthermore, the first element 32 may be formed without branching; for example, the first element 32 may consist only of the first part 33.

[0041] In this embodiment, the first portion 33 and the second portion 34 of the TEL antenna 30 are configured to extend from the third portion 35 so as to be substantially parallel to the ground portion 10. As a result, the TEL antenna 30 has a first portion 33, a second portion 34, and a third portion 35, thereby achieving a wide bandwidth for the TEL antenna 30, while also achieving a low profile for the antenna device 10 because the first portion 33 and the second portion 34 are configured to be substantially parallel to the ground portion 10.

[0042] The TEL antenna 50, like the TEL antenna 30 described above, is a broadband antenna based on a monopole antenna for mobile communications. The TEL antenna 50 of this embodiment supports radio waves in the 1710MHz to 5100MHz (5.1GHz) band for GSM, UMTS, LTE, and 5G. In other words, the TEL antenna 50 is an antenna that supports radio waves in the medium and high frequency bands. However, the TEL antenna 50 is not limited to this, and may support radio waves in some frequency bands (for example, only for 5G) among those for GSM, UMTS, LTE, and 5G. Furthermore, the TEL antenna 50 may support radio waves in frequency bands for telematics, and may also support radio waves in frequency bands other than those for GSM, UMTS, LTE, and 5G.

[0043] The elements of the TEL antenna 50 are formed to have a length and width corresponding to the wavelength used in the frequency band of the corresponding radio wave. Furthermore, as shown in Figures 1 to 4, the TEL antenna 50 is provided at the end of the ground section 10. Specifically, the TEL antenna 50 is provided at the -Y direction end of the ground section 10. However, the location of the ground section 10 on which the TEL antenna 50 is provided is not limited to the -Y direction end, but may be any end of the ground section 10, for example, the +Y direction end. Moreover, the antenna device 100 does not necessarily have to have the TEL antenna 50.

[0044] Furthermore, in this embodiment, the elements of the TEL antenna 50, similar to the TEL antenna 30 described above, have a portion that extends toward the ground portion 10 (a portion that extends in the Z direction) and a portion that branches off from that portion and extends substantially parallel to the ground portion 10 (a portion that extends in the Y direction). As a result, the lengths of the elements of the TEL antenna 50 are different, so the TEL antenna 50 can correspond to different frequency bands. Therefore, the TEL antenna 50 can correspond to radio waves in a wide frequency band. Thus, similar to the TEL antenna 30 in this embodiment, the TEL antenna 50 is also a "broadband antenna based on a monopole antenna". Similar to the TEL antenna 30, the TEL antenna 50 achieves broadband while also achieving a low profile for the antenna device 10.

[0045] In this embodiment, the TEL antenna 50 is formed from a single metal plate (sheet metal). However, the TEL antenna 50 does not have to be formed from a single metal plate; for example, it may be constructed by combining a metal component and a non-metal component, or by physically or electrically connecting multiple metal components. Furthermore, the TEL antenna 50 may be formed from a conductive pattern provided on a printed circuit board.

[0046] The patch antenna 60 is, for example, a planar antenna that corresponds to radio waves from a Global Navigation Satellite System (GNSS). In this embodiment, the patch antenna 60 corresponds to radio waves in the 1.5 GHz band for GNSS. However, the communication standards and frequency bands that the patch antenna 60 corresponds to are not limited to those described above, and other communication standards and frequency bands may also be used. Furthermore, the patch antenna 60 may correspond to radio waves in multiple frequency bands such as the L1 band, L2 band, and L5 band, and only needs to transmit and receive radio waves in the desired frequency band. Moreover, the antenna device 100 does not necessarily have to have the patch antenna 60.

[0047] <<Arm portion 11 of ground portion 10>> As mentioned above, the antenna device 100 of this embodiment has multiple antennas, namely a TEL antenna 30, a TEL antenna 50, and a patch antenna 60. In an antenna device 100 having multiple antennas in this way, there is a need to miniaturize the entire antenna device 100 while ensuring the isolation of each antenna. However, when attempting to miniaturize the antenna device 100, it can be difficult to ensure sufficient element length for, for example, the TEL antenna 30 and the TEL antenna 50.

[0048] Furthermore, the elements of the TEL antenna 30 and TEL antenna 50 have lengths corresponding to the wavelengths used in the frequency band of the radio waves that each antenna corresponds to. However, since the TEL antenna 30 also handles low-frequency radio waves, it can be particularly difficult to ensure the necessary element length for the TEL antenna 30.

[0049] Therefore, in the antenna device 100 of this embodiment, an arm portion 11 is formed in a part of the ground portion 10. The arm portion 11 is a part that can be considered as part of the length of the TEL antenna 30 element, in addition to the first element 32. In other words, in the antenna device 100 of this embodiment, because the arm portion 11 is provided, the corresponding frequency of the TEL antenna 30 can be further lowered (shifted to a lower frequency) by the length of the arm portion 11 from the corresponding frequency determined by the length of the first element (L2 shown in Figures 2 to 4) without increasing the length of the first element. This makes it easy to realize an antenna that corresponds to radio waves in the low frequency band. In the following, the features of the arm portion 11 will be explained with reference to Figures 1 to 4 again, and also with reference to Figures 5 and 6A.

[0050] Figure 5 is a plan view of the ground section 10 on which the substrate 80 is provided. Figure 6A is an enlarged plan view of the area around the substrate 80 in the ground section 10.

[0051] In this embodiment, a slit 70 is formed in the ground portion 10, as shown in Figures 5 and 6A. The slit 70 is a notch formed to provide an arm portion 11 at the end of the ground portion 10. As mentioned above, if the ground portion 10 is composed of a single substrate, the slit 70 may be an insulating portion provided on the substrate. In this case, the arm portion 11 is formed of a conductor pattern. In this embodiment, as shown in Figures 5 and 6A, the slit 70 has an open end 71 on the outer edge of the ground portion 10 and a closed end 72 inside the ground portion 10. That is, the open end 71 is located on the outer edge of the ground portion 10, and the closed end 72 is located inside the ground portion 10.

[0052] Furthermore, in this embodiment, a slit 70 is formed in the ground portion 10, so that the ground portion 10 has an outer edge and an arm portion 11 defined by the slit 70, as shown in Figures 5 and 6A. As described above, the TEL antenna 30 is located at the -X side end of the ground portion 10. Here, the arm portion 11 is also provided at the -X side end of the ground portion 10 where the TEL antenna 30 is located. As a result, the feed portion 31 of the TEL antenna 30 is provided on the arm portion 11. Furthermore, in this embodiment, the feed portion 31 is provided at the tip of the arm portion 11, as shown in Figures 5 and 6A.

[0053] Here, "end portion" refers to the region in which the arm portion 11 is considered as part of the length of the TEL antenna 30, as will be described later, and in which the arm portion 11 and the first element 32 can function as the TEL antenna 30.

[0054] The feed point 31 of the TEL antenna 30 is provided on the arm portion 11, which is defined by the outer edge of the ground portion 10 and the slit 70. As a result, the arm portion 11 can be considered as part of the element length of the TEL antenna 30, in addition to the first element 32. In other words, the sum of the length of the arm portion 11 (L1) and the length of the first element 32 (L2) (L1+L2), as shown in Figures 2 to 4, becomes the element length of the antenna used in the low-frequency band. This makes it easy to secure the element length of the TEL antenna 30, and makes it easy to realize a TEL antenna 30 that can handle low-frequency radio waves.

[0055] In this embodiment, preferably, the sum of the length of the arm portion 11 (L1) and the length of the first element 32 (L2) (L1 + L2) is approximately one-quarter of the wavelength of the low-frequency band. However, the sum of the length of the arm portion 11 and the length of the first element 32 may be other than approximately one-quarter of the wavelength of the low-frequency band. Also, in this embodiment, the length of the arm portion 11 (L1) is less than or equal to the length of the first element 32 (L2) (L1 ≤ L2). However, the length of the arm portion 11 may be greater than the length of the first element 32.

[0056] The length (L2) of the first element 32 is the distance from the end of the first part 33 furthest from the second part 34 to the power supply section 31, as indicated by the dashed arrows in Figures 2 to 4.

[0057] The arm portion 11 is provided to extend in the -Y direction, as shown in Figures 5 and 6A. However, the arm portion 11 is not limited to the shape shown in Figures 5 and 6A, as long as it is provided at the end of the ground portion 10. For example, it may have a meander shape, as shown in Figures 9A and 9B, which will be described later.

[0058] <<Filter 81>> Incidentally, the presence of a slit 70 in the ground section 10 can sometimes worsen the characteristics of the TEL antenna 30 in the mid- and high-frequency bands. Therefore, in the antenna device 100 of this embodiment, a filter 81 is provided so as to straddle the slit 70. The features of the filter 81 will be described below with reference to Figures 5 and 6B.

[0059] Filter 81 is a circuit element that allows signals in the mid- and high-frequency bands to pass through and blocks signals in the low-frequency band, and is composed of, for example, a capacitor C and an inductor L. In this embodiment, filter 81 is a band-stop filter (also called a band-elimination filter). The band-stop filter in this embodiment is a circuit element that blocks the passage of signals in a predetermined frequency band, but for example, a SAW (Surface Acoustic Wave) filter may be used.

[0060] Figure 6B is an explanatory diagram of filter 81 as a band stop filter.

[0061] As shown in Figure 6B, the filter 81, which acts as a band-stop filter, is configured as a parallel resonant circuit with a capacitor C and an inductor L. One terminal T1 of the filter 81 is connected to the ground portion 10 on one side of the slit 70, and the other terminal T2 is connected to the ground portion 10 on the other side of the slit 70. In this way, the filter 81 is provided so as to straddle the slit 70.

[0062] By using a bandstop filter 81 as the filter that spans the slit 70, signals in the mid- and high-frequency bands can be allowed to pass through the slit 70, while signals in the low-frequency bands can be blocked from passing through the slit 70. In other words, with respect to signals in the mid- and high-frequency bands, it is as if the slit 70 does not exist. This makes it possible to suppress the deterioration of the mid- and high-frequency characteristics of the TEL antenna 30 caused by the slit 70. However, in the antenna device 100, it is not necessary to provide the filter 81 in the slit 70.

[0063] Furthermore, in order to block the passage of low-frequency signals and allow the passage of mid- and high-frequency signals, a bandpass filter can also be used as filter 81. A bandpass filter is a circuit element that allows signals of a predetermined frequency band to pass through. Therefore, by using a bandpass filter that allows mid- and high-frequency signals to pass through as filter 81 that crosses the slit 70, it is possible to allow mid- and high-frequency signals to pass through the slit 70 while blocking the passage of low-frequency signals.

[0064] However, if the filter 81 is provided so as to straddle the slit 70, a band-stop filter is preferred in which a parallel resonant circuit composed of a capacitor C and an inductor L can be connected to the ground portions 10 on both sides of the slit 70.

[0065] In this embodiment, as shown in Figure 6A, the distance D between the open end 71 and the filter 81 is within approximately one-eighth of the wavelength used in the mid- and high-frequency bands. However, the distance D between the open end 71 and the filter 81 may be greater than approximately one-eighth of the wavelength used in the mid- and high-frequency bands.

[0066] Figures 7A to 7C are explanatory diagrams of antenna devices 100, 100X, and 100Y. Figures 7A to 7C briefly illustrate the configurations of antenna devices 100, 100X, and 100Y in order to verify the presence or absence of the slit 70 (arm portion 11) in the ground portion 10, and the presence or absence of the filter 81 when the slit 70 is formed in the ground portion 10.

[0067] Figure 7A is a diagram illustrating the antenna device 100. The antenna device 100 shown in Figure 7A is the antenna device 100 of this embodiment, and has an arm portion 11 formed by a slit 70 in the ground portion 10, and a filter 81 is provided in the slit 70. Note that the slit 70, arm portion 11 and filter 81 are the same as those of the antenna device 100 of this embodiment.

[0068] Figure 7B is a diagram illustrating the antenna device 100X. Compared to the antenna device 100, the antenna device 100X is a configuration in which the slit 70 filter 81 is not provided, but the other configurations are the same as those of the antenna device 100.

[0069] Figure 7C is a diagram illustrating antenna device 100Y. Compared to antenna device 100, antenna device 100Y lacks the slit 70 (arm portion 11) and filter 81, but its other configurations are the same as antenna device 100. Furthermore, compared to antenna device 100X, antenna device 100Y lacks the slit 70, but its other configurations are the same as antenna device 100X.

[0070] Figure 8 is a graph showing an example of the frequency characteristics of antenna devices 100, 100X, and 100Y. In this figure, the horizontal axis represents frequency, and the vertical axis represents the voltage standing wave ratio (VSWR). In Figure 8, the calculation results for antenna device 100 are shown as a solid line, the calculation results for antenna device 100X are shown as a dashed line, and the calculation results for antenna device 100Y are shown as a dotted line.

[0071] First, to verify the effect of the slit 70 (arm section 11), we compare the calculation results for antenna device 100X (dotted line) and antenna device 100Y (dotted line). As shown in Figure 8, focusing on the low frequency band, particularly the 700MHz to 1000MHz range, the VSWR characteristics of antenna device 100X (dotted line) are significantly improved compared to the VSWR characteristics of antenna device 100Y (dotted line). In other words, it can be seen that the low frequency band characteristics of the TEL antenna 30 are improved by providing the slit 70 (arm section 11) in the ground section 10. However, as shown in Figure 8, focusing on the mid- and high frequency bands, particularly the 2300MHz to 3200MHz range, the VSWR characteristics of antenna device 100X (dotted line) are significantly worse compared to the VSWR characteristics of antenna device 100Y (dotted line). In other words, it can be seen that the presence of the slit 70 in the ground section 10 degrades the characteristics of the TEL antenna 30 in the mid- and high-frequency ranges.

[0072] Next, to verify the effect of filter 81, we compare the calculation results for antenna device 100 (solid line) and antenna device 100X (dotted line). As shown in Figure 8, focusing on the low frequency band, particularly the range of 700MHz to 1000MHz, the VSWR characteristics of antenna device 100 (solid line) are almost unchanged compared to the VSWR characteristics of antenna device 100X (dotted line). In other words, even if filter 81 is provided in slit 70, it does not adversely affect the low frequency band characteristics of the TEL antenna 30. Furthermore, as shown in Figure 8, focusing on the mid- and high frequency bands, particularly the range of 2300MHz to 3200MHz, the VSWR characteristics of antenna device 100 (solid line) are significantly improved compared to the VSWR characteristics of antenna device 100X (dotted line). In other words, the provision of filter 81 in slit 70 improves the mid- and high frequency band characteristics of the TEL antenna 30.

[0073] As described above, the antenna device 100 of this embodiment, by providing a slit 70 (arm portion 11) in the ground portion 10, can easily realize a TEL antenna 30 that responds to low-frequency radio waves, while suppressing deterioration of the characteristics of the TEL antenna 30 in the medium and high-frequency bands due to the slit 70.

[0074] <<Ground element 16>> As described above, in this embodiment, the first element 32 of the TEL antenna 30 has a length that corresponds to low-frequency radio waves. However, the first element 32 alone may have difficulty securing bandwidth in the low-frequency range.

[0075] Therefore, in this embodiment, the ground section 10 has a ground-side element 16 that is formed to rise from the ground section 10. The ground-side element 16 is an element that capacitively couples with the first portion 33 of the first element 32. The ground-side element 16 is provided at a position where the tip of the first element 32 (first portion 33) of the TEL antenna 30 is capacitively coupled. The ground-side element 16 is an unpowered element.

[0076] The predetermined frequency band that the ground-side element 16 corresponds to is slightly lower than the low-frequency band that the TEL antenna 30 corresponds to. The length L5 of the ground-side element 16 shown in Figure 2 corresponds to the predetermined frequency band mentioned above. The ground section 10 has a slit 74 with a closed end 75 formed inside it. The length L5 of the ground-side element 16 is the sum of the length L3 of the region in the ground section 10 where the slit 74 is formed and the length L4 of the portion that rises from the ground section 10.

[0077] Furthermore, as described above, the ground-side element 16 is capacitively coupled to the first part 33 of the first element 32 (TEL antenna 30). Therefore, the frequency band that the TEL antenna 30 corresponds to can be a band that is an overlap of the frequency band that the TEL antenna 30 alone corresponds to and the frequency band that the ground-side element 16 corresponds to. This makes it possible to extend the bandwidth of the low-frequency band that the TEL antenna 30 corresponds to. However, the predetermined frequency band that the ground-side element 16 corresponds to may be a slightly higher bandwidth than the low-frequency band that the TEL antenna 30 corresponds to. In the following description, the ground-side element 16 may be referred to as the "second element".

[0078] In the antenna device 100 of this embodiment, the ground-side element 16 rises from the -X-side end of the ground section 10 and extends in the +X direction opposite to the ground section 10, as shown in Figure 2. However, the shape of the ground-side element 16, including the direction in which it extends, is not limited to this; it may be inclined at a predetermined angle with respect to the ground section 10, or it may be provided to extend in the +Z direction with respect to the ground section 10. However, in that case, it is necessary that the tip of the first element 32 (first section 33) of the TEL antenna 30 is provided at a position where it capacitively couples.

[0079] <<Notches 19A~19C>> As described above, the first element 32 of the TEL antenna 30 has a first portion 33 that faces the ground portion 10. Because the first portion 33 faces the ground portion 10, the tip of the first portion 33 and the ground portion 10 may couple, which can degrade the characteristics of the TEL antenna 30. Similarly, the relationship between the ground-side element 16 and the ground portion 10, and the relationship between the elements of the TEL antenna 50 and the ground portion 10 can also be problematic.

[0080] Therefore, in this embodiment, the ground portion 10 has notches 19A to 19C formed in it, as shown in Figures 2 and 3. The notches 19A to 19C are formed to suppress the deterioration of the antenna's characteristics caused by the coupling between the ground portion 10 and the antenna element facing the ground portion 10.

[0081] As shown in Figures 2 and 3, the notch 19A is formed such that, when viewed from the Z direction (a direction perpendicular to the ground portion 10), it has a region that does not overlap with a part of the first portion 33 of the first element 32 of the TEL antenna 30. By forming the notch 19A in the ground portion 10, the distance between the first portion 33 and the ground portion 10 can be increased. Therefore, the characteristics of the TEL antenna 30 can be improved.

[0082] Furthermore, the notch 19B is formed such that, when viewed from the Z direction (a direction perpendicular to the ground portion 10), it has a region that does not overlap with a part of the ground-side element 16. By forming the notch 19B in the ground portion 10, the distance between the tip of the ground-side element 16 and the ground portion 10 other than the ground-side element 16 can be increased. Therefore, the characteristics of the TEL antenna 30 having the first element 32 that capacitively couples with the ground-side element 16 can be improved.

[0083] Furthermore, the notch 19C is formed such that, when viewed from the Z direction (a direction perpendicular to the ground portion 10), it has a region that does not overlap with the elements of the TEL antenna 50. By forming the notch 19C in the ground portion 10, the distance between the elements of the TEL antenna 50 and the ground portion 10 can be increased. Therefore, the characteristics of the TEL antenna 50 can be improved.

[0084] Note that the notches 19A to 19C are not limited to the shapes shown in Figures 2 and 3. For example, each of the notches 19A to 19C in this embodiment may be formed to have a region that does not overlap with all of the antenna elements, rather than being part of the antenna elements. Also, the notches 19A to 19C do not need to be empty spaces, and other members, such as insulators, may be inserted into the notches 19A to 19C as long as they do not affect the characteristics of the antenna elements.

[0085] Furthermore, the ground portion 10 may have some of the notches 19A to 19C formed in it (for example, only notch 19A), or it may not have all of the notches 19A to 19C formed in it.

[0086] <<Modified form of arm portion 11 and slit 70>> Figures 9A to 9C illustrate modified examples of the arm portion 11 and slit 70 of the ground portion 10.

[0087] Figure 9A illustrates the first modified example. In the first modified example, the slit 70 and the arm portion 11 have a meander shape. That is, the slit 70 includes at least one fold 73 in a predetermined direction, and the arm portion 11 also includes at least one fold 12 in a predetermined direction. As a result, the length L1 of the arm portion 11 is the length along the fold in the predetermined direction, so that the corresponding frequency of the first element 32 of the TEL antenna 30 can be made lower. Therefore, a first element 32 corresponding to a low frequency band can be easily realized.

[0088] Figure 9B illustrates a second modified example. In the second modified example, similar to the first modified example, there is no fold in the slit 70, but the arm portion 11 includes at least one fold 12 in a predetermined direction. This allows the length L1 of the arm portion 11 to be increased, and the corresponding frequency of the first element 32 of the TEL antenna 30 can be made lower. Therefore, a first element 32 corresponding to a low frequency band can be easily realized.

[0089] Figure 9C illustrates a third modified example. In this third modified example, by forming the slit 70 in an L-shape, the length L1 of the arm portion 11 can be increased, and the corresponding frequency of the first element 32 of the TEL antenna 30 can be made lower. Therefore, a first element 32 corresponding to a low frequency band can be easily realized.

[0090] ==Summary== The antenna device 100 of this embodiment has been described above. The antenna device 100 of this embodiment includes, for example, a ground section 10, a feed section 31 provided at the end of the ground section 10, and a first element 32 extending from the feed section 31, and comprises a TEL antenna 30 (antenna) corresponding to at least a first frequency band (for example, 614 MHz to 960 MHz). The antenna device 100 also includes, for example, an arm section 11 defined by the outer edge of the ground section 10 and a slit 70 having an open end 71 located at the outer edge and a closed end 72 located inside the ground section 10, as shown in Figures 5 and 6A, and the feed section 31 is provided on the arm section 11. According to the antenna device 100 of this embodiment, an antenna element (first element) corresponding to a low frequency band can be easily realized.

[0091] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 1, 3, 5, and 6A, the power supply unit 31 is provided at the tip of the arm unit 11. This makes it easy to realize an antenna element (first element) that corresponds to a low frequency band.

[0092] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 2 to 4, the sum of the length of the arm portion 11 (L1) and the length of the first element 32 (L2) (L1 + L2) is approximately one-quarter of the wavelength of the first frequency band (for example, 614 MHz to 960 MHz). This makes it easy to realize an antenna element (first element) that corresponds to a lower frequency band.

[0093] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 2 to 4, the length (L1) of the arm portion 11 is less than or equal to the length (L2) of the first element 32 (L1 ≤ L2). This makes it easy to realize an antenna element (first element) that corresponds to a low frequency band.

[0094] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 9A and 9A, the arm portion 11 includes at least one fold 12 in a predetermined direction. This makes it easy to realize an antenna element (first element) that corresponds to a low frequency band.

[0095] Furthermore, in the antenna device 100 of this embodiment, as shown in Figures 1 to 3 and 5 to 7A, the first element 32 is provided to further correspond to a second frequency band (e.g., 1710 MHz to 5100 MHz) that is higher than the first frequency band (e.g., 614 MHz to 960 MHz), and is provided so as to straddle the slit 70, and includes a filter 81 that allows signals in the second frequency band to pass through. This makes it possible to suppress the degradation of the characteristics of the antenna element (first element) in the mid- and high-frequency bands due to the slit 70.

[0096] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figure 6A, the filter 81 is located within approximately one-eighth of the wavelength of the second frequency band (for example, 1710 MHz to 5100 MHz) from the open end 71. This makes it possible to suppress the degradation of the characteristics of the antenna element (first element) in the mid- and high-frequency bands due to the slit 70.

[0097] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figure 6B, the filter 81 is a band-stop filter that blocks the passage of signals in the first frequency band (for example, 614 MHz to 960 MHz). This makes it possible to suppress the degradation of the characteristics of the antenna element (first element) in the mid- and high-frequency bands caused by the slit 70.

[0098] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figure 2 or Figure 3, the first element 32 has a first portion 33 and a second portion 34, each facing the ground portion 10. This allows the bandwidth of the corresponding frequency band of the antenna element (first element) to be extended.

[0099] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figure 2 or Figure 3, the first element 32 has a third portion 35 connected to the feed unit 31. This makes it possible to extend the bandwidth of the corresponding frequency band of the antenna element (first element).

[0100] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 1 to 5, a ground-side element 16 (second element) is provided, which is part of the ground section 10 and is formed to rise from the ground section 10, and the ground-side element 16 is provided to be capacitively coupled with the first element 32. This makes it possible to extend the bandwidth of the corresponding frequency band of the antenna element (first element).

[0101] Furthermore, in the antenna device 100 of this embodiment, for example, as shown in Figures 2 and 3, in a plan view taken from a direction perpendicular to the ground portion 10, the ground portion 10 has a cutout portion 19A such that it has a region that does not overlap with at least a part of the first element 32. This makes it possible to improve the characteristics of the antenna element (first element).

[0102] In this embodiment, "vehicle-mounted" means that it can be placed on a vehicle, and therefore it is not limited to devices attached to a vehicle, but also includes devices that are brought into a vehicle and used inside the vehicle. Furthermore, although the antenna device in this embodiment is intended to be used on a "vehicle," which is a wheeled vehicle, it is not limited to this, and may also be used on other mobile devices such as drones and other flying objects, probes, construction machinery without wheels, agricultural machinery, ships, etc.

[0103] The embodiments described above are provided to facilitate understanding of the present invention and are not intended to limit its interpretation. Furthermore, the present invention may be modified or improved without departing from its spirit, and it goes without saying that equivalents thereof are included. [Explanation of Symbols]

[0104] 10. Grounds Department 11 Arm 12 Turning around 16. Ground-side element (second element) 19A~19C Notches 20 holders 30 TEL antenna (antenna) 31 Power supply section 32 First Element 33 Part 1 34 Part 2 35 Part 3 50 TEL antenna 60 Patch Antenna 70, 74 slits 71 Open end 72,75 Closed end 73 Turnaround 80, 90 boards 81 Filters 100 Antenna equipment

Claims

1. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The sum of the length of the arm and the length of the first element is approximately one-quarter of the wavelength of the first frequency band. Antenna device.

2. The power supply unit is provided at the tip of the arm, The antenna device according to claim 1.

3. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The length of the arm is less than or equal to the length of the first element. The sum of the length of the arm and the length of the first element is equal to the wavelength of the first frequency band. It is approximately one-quarter. Antenna device.

4. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The arm portion includes at least one fold in a predetermined direction. Antenna device.

5. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The first element further corresponds to a second frequency band higher than the first frequency band, A filter is provided that straddles the aforementioned slit and allows the signal of the second frequency band to pass through. Antenna device.

6. The filter is located within approximately one-eighth the wavelength of the second frequency band from the open end. The antenna device according to claim 5.

7. The filter is a band-stop filter that blocks the passage of signals in the first frequency band. The antenna device according to claim 5 or 6.

8. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The first element has a first portion and a second portion, each facing the ground portion. Antenna device.

9. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, The first element has a third portion connected to the power supply unit, The sum of the length of the arm and the length of the first element is equal to the wavelength of the first frequency band. It is approximately one-quarter. Antenna device.

10. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, A part of the ground portion comprises a second element formed to rise up from the ground portion, The second element is provided to be capacitively coupled with the first element. Antenna device.

11. The Ground Club and, An antenna provided at the end of the ground section, having a power supply section and a first element extending from the power supply section, and corresponding to at least a first frequency band, Equipped with, The ground portion has an arm portion defined by the outer edge of the ground portion and a slit having an open end located at the outer edge and a closed end located inside the ground portion. The power supply unit is provided on the arm, In a plan view taken from a direction perpendicular to the ground portion, The ground portion is formed with a notch so as to have a region that does not overlap with at least a part of the first element. Antenna device.

12. The sum of the length of the arm and the length of the first element is equal to the wavelength of the first frequency band. It is approximately one-quarter. The antenna device according to any one of claims 4 to 6, 8, 10, and 11.

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