Antenna equipment

Abstract

To provide an antenna device having directivity with a structure capable of being miniaturized while increasing bandwidth than before.SOLUTION: An antenna device 10a includes: a radiator 13 that has a plate-like first antenna element 11, and a plate-like second antenna element 12 with a width smaller than the first antenna element 11 and has one side 12a connected to one side 11a of the first antenna element 11 via a power supply part, which is placed on the same plane as the first antenna element 11; and a parasitic reflective plate 14 which has a plate shape and is placed on a plane facing the radiator 13. The reflective plate 14 has a first cutout 14a having a first opening 14b which is formed in a first side 141 extending in the y-axis direction of the reflective plate 14.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present disclosure relates to an antenna device, and more particularly to an antenna device having a directional and miniaturizable structure.

Background Art

[0002] In recent years, the spread of IoT (Internet of Things) terminals has been rapidly progressing worldwide. Antennas for IoT terminals are required to be miniaturized from the viewpoints of designability and mobility. In addition, when there are a human body, a metal object, etc. near the antenna, its performance deteriorates, so it is necessary to be strong against surrounding objects. In order to reduce the influence of surrounding metal objects, etc., an antenna having single directivity is effective. Therefore, it is desirable that the antenna for IoT terminals is small and has single directivity.

[0003] Therefore, conventionally, an antenna device having a miniaturizable structure in which a power-free reflector is provided facing the radiator and the directivity to the opposite side of the reflector is enhanced by electromagnetic coupling between the radiator and the reflector has been proposed (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, although the antenna device of Patent Document 1 has a structure that enables miniaturization with enhanced directivity, further broadbanding is required depending on the communication system.

[0006] Therefore, an object of the present disclosure is to provide an antenna device having a directional and miniaturizable structure, in which broadbanding has been achieved more than before. [Means for solving the problem]

[0007] To achieve the above objective, an antenna device according to one embodiment of the present disclosure is a directional antenna device used in connection with a power supply unit, comprising: a radiator having a first antenna element which is plate-shaped and has a width in a first direction and extends in a second direction perpendicular to the first direction; and a second antenna element which is arranged on the same plane as the first antenna element, has a smaller width than the first antenna element, and has one side connected to one side of the first antenna element via the power supply unit; and a plate-shaped and non- The antenna device comprises a power supply reflector, the reflector having a first notch with a first opening on the first side extending in the second direction of the reflector, the reflector having a length longer than the radiator, the second antenna element having a length shorter than 1 / 4 of the wavelength of the operating frequency, the radiator and the reflector being separated by an electromagnetic coupling distance, the resistive component of the input impedance of the antenna device being adjusted by the length of the first antenna element, and the reactance component of the input impedance of the antenna device being adjusted by the length of the second antenna element. The first notch is formed in a position that overlaps with at least one of the first antenna element and the second antenna element when the antenna device is viewed from above. [Effects of the Invention]

[0008] This disclosure provides an antenna device that is directional, has a miniaturizable structure, and offers a wider bandwidth than conventional antenna devices. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an external view showing the structure of the antenna device according to the first reference example. [Figure 2] Figure 2 shows the antenna characteristics of the antenna device according to the first reference example. [Figure 3] Figure 3 is a Smith chart showing the impedance characteristics when the length of the first antenna element is changed by 1 mm increments in the antenna device according to the first reference example. [Figure 4] Figure 4 is a Smith chart showing the impedance characteristics of the antenna device according to the first reference example when the length of the second antenna element is changed in 1 mm increments. [Figure 5] Figure 5 is an external view showing the structure of the antenna device according to the second reference example. [Figure 6] Figure 6 shows the antenna characteristics of the antenna device according to the second reference example. [Figure 7] Figure 7 is an external view showing the structure of the antenna device according to Embodiment 1. [Figure 8] Figure 8 is an external view showing the structure of the antenna device according to Embodiment 1 of Embodiment 1. [Figure 9] Figure 9 shows the antenna characteristics of the antenna device according to Embodiment 1 of Embodiment 1. [Figure 10] Figure 10 is an external view showing the structure of the antenna device according to Embodiment 2 of Embodiment 1. [Figure 11] Figure 11 shows the antenna characteristics of the antenna device according to Embodiment 2 of Embodiment 1. [Figure 12] Figure 12 is an external view showing the structure of the antenna device according to Embodiment 3 of Embodiment 1. [Figure 13] Figure 13 shows the antenna characteristics of the antenna device according to Embodiment 3 of Embodiment 1. [Figure 14] Figure 14 is an external view showing the structure of the antenna device according to Embodiment 1 of Embodiment 2. [Figure 15] Figure 15 shows the antenna characteristics of the antenna device according to Embodiment 1 of Embodiment 2. [Figure 16] Figure 16 is an external view showing the structure of the antenna device according to Embodiment 2 of Embodiment 2. [Figure 17] Figure 17 shows the antenna characteristics of the antenna device according to Embodiment 2 of Embodiment 2. [Figure 18] Figure 18 is an external view showing the structure of the antenna device according to Embodiment 1 of Embodiment 3. [Figure 19]FIG. 19 is a diagram showing the antenna characteristics of the antenna device according to Example 1 of Embodiment 3. [Figure 20] FIG. 20 is an external view showing the structure of the antenna device according to Example 2 of Embodiment 3. [Figure 21] FIG. 21 is a diagram showing the antenna characteristics of the antenna device according to Example 2 of Embodiment 3. [Figure 22] FIG. 22 is an external view showing the structure of the antenna device according to Example 3 of Embodiment 3. [Figure 23] FIG. 23 is a diagram showing the antenna characteristics of the antenna device according to Example 3 of Embodiment 3. [Figure 24] FIG. 24 is an external view showing the structure of the antenna device according to Embodiment 4.

MODE FOR CARRYING OUT THE INVENTION

[0010] (Antenna device according to the reference example) Before explaining the embodiments of the present disclosure, two examples of an antenna device for the 2.4 GHz band (the operating frequency is 2.45 GHz, which is the approximate center frequency, and the wavelength is about 122 mm) based on the technology according to Patent Document 1 will be described as an antenna device according to the reference example.

[0011] (First reference example) FIG. 1 is an external view showing the structure of an antenna device 9a according to the first reference example. More specifically, FIGS. 1(a) to 1(f) are a perspective view, a top view, a bottom view, a side view, a dimension view on the top surface, and a dimension view on the bottom surface of the antenna device 9a, respectively. The antenna device 9a is generally long and rectangular. The width direction is defined as the x-axis (also referred to as the "first direction"), the direction perpendicular to the x-axis and extending longitudinally is defined as the y-axis (also referred to as the "second direction"), and the direction perpendicular to the x-axis and the y-axis is defined as the z-axis.

[0012] The antenna device 9a is a directional antenna used in connection with a feed unit (not shown), and comprises a radiator 13 having a first antenna element 11 which is plate-shaped with width in the x-axis direction and extending in the y-axis direction, and a second antenna element 12 which is plate-shaped with width in the x-axis direction and extending in the y-axis direction, has a smaller width than the first antenna element 11, and has one side 12a which is connected to one side 11a of the first antenna element 11 via a feed unit, and a non-feeding reflector 14 which is plate-shaped with width in the x-axis direction and extending in the y-axis direction, and is arranged in a plane opposite to the radiator 13. The second antenna element 12 may be inverted L-shaped, and its shape is not limited to a straight shape.

[0013] Here, the reflector 14 has a length longer than the radiator 13, the second antenna element 12 has a length shorter than 1 / 4 of the wavelength of the operating frequency, and the radiator 13 and the reflector 14 are spaced apart to allow electromagnetic coupling. The reflector 14 may have a length that functions as a reflector, and may be at least 1 / 2 of the wavelength of the operating frequency. The resistive component of the input impedance of the antenna device 9a is adjusted by the length of the first antenna element 11, and the reactance component of the input impedance of the antenna device 9a is adjusted by the length of the second antenna element 12.

[0014] Furthermore, when specifying the length or width of each component using the wavelength (λ) of the operating frequency, the wavelength (λ) may be the value obtained by multiplying it by the wavelength shortening factor determined according to the relative permittivity of each component (electrical length). Also, "plate-shaped" means a flat plate whose length or width is sufficiently large compared to its thickness (for example, more than twice as large), and the external shape in plan view is not limited to a rectangle, but may be any shape such as an ellipse. "Rectangular" means a rectangle. Furthermore, when simply written as "plan view," it means a plan view relative to the antenna device.

[0015] The specific structure of the antenna device 9a is as follows:

[0016] A substrate 15 made of FR-4 (Flame Retardant Type 4) with a relative permittivity εr = 4.6 is used. The external dimensions of the substrate 15 are length L50 mm × width W6 mm × thickness t1.2 mm. Both the radiator 13 (first antenna element 11 and second antenna element 12) and the reflector 14 are formed from copper foil on the substrate 15.

[0017] The antenna device 9a consists of a radiator 13, which is formed by connecting a power supply unit to the gap g between a first antenna element 11 with length l1 × width w1 and a second antenna element 12 with length l2 × width w2, and a reflector 14 with length l3 × width w3. The distance from the edge of the substrate (the edge of the substrate 15 in the positive y-axis direction) to the first antenna element 11 is d, and the area 0.5 mm from the edge of the substrate (0.5 mm from the four edges toward the center on both sides of the substrate 15) is a prohibited area for copper foil patterns.

[0018] The resonant frequency of the antenna device 9a can be tuned by controlling the resistive component of the impedance of the antenna device 9a with the length l1 of the first antenna element 11, and by controlling the reactance component of the impedance of the antenna device 9a with the length l2 of the second antenna element 12.

[0019] In the antenna device 9a of this reference example, the second antenna element 12 is positioned such that the center of one side 11a of the first antenna element 11 faces one side 12a of the second antenna element 12. The dimensions are, for example, L=50mm, W=6mm, t=1.2mm, d=17mm, g=0.5mm, l1=25.5mm, w1=5mm, l2=9mm, w2=1mm, l3=49mm, and w3=5mm.

[0020] To explain each of these dimensions in relation to the wavelength λ (approximately 122 mm, electrical length approximately 57 mm (=122 / √4.6)) at the operating frequency (2.45 GHz), the length l1 of the first antenna element 11 is approximately 0.4 (=25.5 × √4.6 / 122)λ, and the length l2 of the second antenna element 12 is approximately 0.2 (=9 × √4.6 / 122)λ.

[0021] Power is supplied from the feed unit (not shown) to the radiator 13 from the top side of the antenna device 9a. The gap between one side 11a of the first antenna element 11 and one side 12a of the second antenna element 12, which are connected to the feed unit (not shown), is also called the "feed point".

[0022] Figure 2 shows the antenna characteristics of the antenna device 9a according to the first reference example shown in Figure 1. More specifically, Figure 2(a) is a Smith chart showing the impedance characteristics of the antenna device 9a according to the first reference example, and Figure 2(b) shows the VSWR (Voltage Standing Wave Ratio) characteristics of the antenna device 9a according to the first reference example. As can be seen from Figure 2(a), the antenna device 9a according to the first reference example is resonant at the operating frequency (2.45 GHz). Also, as can be seen from Figure 2(b), the antenna device 9a according to the first reference example has a bandwidth of 420 MHz for VSWR ≤ 2.

[0023] Figure 3 is a Smith chart showing the impedance characteristics of the antenna device 9a according to the first reference example shown in Figure 1, when the length l1 of the first antenna element 11 is changed in 1 mm increments from 23.5 mm to 27.5 mm. Here, dimensions other than the length l1 of the first antenna element 11 are fixed. As can be seen from Figure 3, the resistance component of the impedance of the antenna device 9a is controlled by the length l1 of the first antenna element 11.

[0024] Figure 4 is a Smith chart showing the impedance characteristics of the antenna device 9a according to the first reference example shown in Figure 1, when the length l2 of the second antenna element 12 is changed from 7 mm to 11 mm in 1 mm increments. Here, dimensions other than the length l2 of the second antenna element 12 are fixed. As can be seen from Figure 4, the reactance component of the impedance of the antenna device 9a is controlled by the length l2 of the second antenna element 12.

[0025] (2nd reference example) Figure 5 is an external view showing the structure of the antenna device 9b according to the second reference example. More specifically, Figures 5(a) to (f) are a perspective view, top view, bottom view, side view, top dimension view, and bottom dimension view of the antenna device 9b, respectively. The antenna device 9b has the same configuration as the antenna device 9a according to the first reference example, except for the arrangement position and size of the second antenna element 12.

[0026] In other words, in the antenna device 9b according to the second reference example, one side 12a of the second antenna element 12 faces the first end 11b of one side 11a of the first antenna element 11. That is, one side 12a of the second antenna element 12 is positioned not in the center of one side 11a of the first antenna element 11, but at a position corresponding to the first end 11b. The size of the second antenna element 12 is a length l2 of 9.5 mm, or approximately 0.2 (=9.5 × √4.6 / 122)λ. All other dimensions are the same as those of the antenna device 9a according to the first reference example.

[0027] Figure 6 shows the antenna characteristics of the antenna device 9b according to the second reference example shown in Figure 5. More specifically, Figure 6(a) is a Smith chart showing the impedance characteristics of the antenna device 9b according to the second reference example, and Figure 6(b) shows the VSWR characteristics of the antenna device 9b according to the second reference example. As can be seen from Figure 6(a), the antenna device 9b according to the second reference example resonates at the operating frequency (2.45 GHz), similar to the antenna device 9a according to the first reference example. Also, as can be seen from Figure 6(b), the antenna device 9b according to the second reference example has a bandwidth of 420 MHz for VSWR ≤ 2, similar to the antenna device 9a according to the first reference example.

[0028] Thus, the antenna device 9a according to the first reference example and the antenna device 9b according to the second reference example have a directional structure that can reduce the influence of surrounding metal objects, etc., by being provided with a reflector 14, and also have a compact structure.

[0029] (Antenna device according to an embodiment) In the following, examples of further widening of the antenna bandwidth are described in Embodiments 1 to 4 as examples of improving the antenna performance of the antenna device 9a according to the first reference example and the antenna device 9b according to the second reference example.

[0030] The embodiments of this disclosure will be described in detail below with reference to the drawings. The embodiments described below are all specific examples of this disclosure. The numerical values, shapes, materials, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, the figures are not necessarily strictly illustrative. In each figure, substantially identical components are denoted by the same reference numerals, and redundant explanations are omitted or simplified. The meanings of terms and the x, y, and z axes are the same as those described for antenna device 9a in the first reference example and antenna device 9b in the second reference example.

[0031] Each embodiment is based on the antenna device 9a according to the first reference example, the antenna device 9b according to the second reference example, or an antenna device similar thereto, and incorporates improvements. The improvements will be described below in detail.

[0032] (Embodiment 1) First, as Embodiment 1, we will describe an antenna device based on the antenna device 9b according to the second reference example, in which a single notch is provided in the reflector plate 14.

[0033] Figure 7 is an external view showing the structure of the antenna device 10a according to Embodiment 1. More specifically, (a1), (a2), (b), and (c) in Figure 7 are perspective views of the top, bottom, top, and bottom of the antenna device 10a, respectively.

[0034] Antenna device 10a corresponds to antenna device 9b in the second reference example shown in Figure 5, in which a notch (here, a first notch 14a) is formed in the reflector plate 14 on the bottom surface. In other words, the reflector plate 14 has a notch (here, a first notch 14a) with an opening (here, a first opening 14b) on the side extending in the y-axis direction of the reflector plate 14 (here, a first side 141). Antenna device 10a having such a structure makes it possible to broaden the bandwidth.

[0035] Furthermore, since the antenna device 10a according to this embodiment is based on the antenna device 9b according to the second reference example, the positional relationship between the first antenna element 11 and the second antenna element 12 is the same as that of the antenna device 9b according to the second reference example; that is, one side 12a of the second antenna element 12 faces the first end 11b of one side 11a of the first antenna element 11. Also, unless otherwise specified, the dimensions are the same as those of the antenna device 9b according to the second reference example.

[0036] The following describes specific examples of antenna devices in which a single notch is provided in the reflector plate 14, based on the antenna device 9b of the second reference example, as Examples 1 to 3 of Embodiment 1.

[0037] (Example 1 of Embodiment 1) Figure 8 is an external view showing the structure of the antenna device 10a1 according to Embodiment 1 of Embodiment 1. More specifically, Figures 8(a) and 8(b) are a top view and a bottom view of the antenna device 10a1 according to Embodiment 1 of Embodiment 1, respectively. In this embodiment, the first notch 14a is formed in a position that overlaps only with the second antenna element 12 of the first antenna element 11 and the second antenna element 12 when the antenna device 10a1 is viewed from above.

[0038] The dimensions of the first notch 14a are 3 mm x 3 mm, and the first notch 14a is formed such that it has a 3 mm first opening 14b at a position that divides one side of the reflector 14 extending in the y-axis direction into a 34 mm portion and a 12 mm portion.

[0039] Figure 9 shows the antenna characteristics of the antenna device 10a1 according to Embodiment 1. More specifically, Figure 9(a) is a Smith chart showing the impedance characteristics of the antenna device 10a1 according to Embodiment 1, and Figure 9(b) shows the VSWR characteristics of the antenna device 10a1 according to Embodiment 1.

[0040] As can be seen from Figure 9(a), the antenna device 10a1 according to Embodiment 1 of Embodiment 1 is resonant at the operating frequency (2.45 GHz). Furthermore, a kink is observed in the impedance characteristics, which is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the 34 mm long reflector 14 separated by the first notch 14a and the radiator 13.

[0041] Furthermore, as can be seen from Figure 9(b), the antenna device 10a1 according to Embodiment 1 of Embodiment 1 has a bandwidth of 520 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the antenna device 9b according to the base Second Reference Example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 9(a).

[0042] (Example 2 of Embodiment 1) Figure 10 is an external view showing the structure of the antenna device 10a2 according to Embodiment 1, Example 2. More specifically, Figures 10(a) and 10(b) are a top view and a bottom view of the antenna device 10a2 according to Embodiment 1, Example 2, respectively. In this embodiment, the first notch 14a is formed in a position that overlaps with the first antenna element 11 and the second antenna element 12 when the antenna device 10a2 is viewed from above. By providing the first notch 14a in this position, as will be described later using Figure 24, a through-hole is provided in the area of ​​the first notch 14a, making it possible to supply power to the first antenna element 11 and the second antenna element 12 from the bottom surface of the substrate 15 of the antenna device 10d (the area of ​​the first notch 14a) through the through-hole.

[0043] The dimensions of the first notch 14a are 3 mm x 3 mm, and the first notch 14a is formed such that it has a 3 mm first opening 14b at a position that divides one side of the reflector 14 extending in the y-axis direction into a 31 mm portion and a 15 mm portion.

[0044] Figure 11 shows the antenna characteristics of the antenna device 10a2 according to Embodiment 1, Example 2. More specifically, Figure 11(a) is a Smith chart showing the impedance characteristics of the antenna device 10a2 according to Embodiment 1, Example 2, and Figure 11(b) shows the VSWR characteristics of the antenna device 10a2 according to Embodiment 1, Example 2.

[0045] As can be seen from Figure 11(a), the antenna device 10a2 according to Embodiment 1, Example 2, is resonant at the operating frequency (2.45 GHz). Furthermore, a kink is observed in the impedance characteristics, which is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the 31 mm long reflector 14 separated by the first notch 14a and the radiator 13.

[0046] Furthermore, as can be seen from Figure 11(b), the antenna device 10a2 according to Embodiment 2 of Embodiment 1 has a bandwidth of 540 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 11(a).

[0047] (Example 3 of Embodiment 1) Figure 12 is an external view showing the structure of the antenna device 10a3 according to Embodiment 1, Example 3. More specifically, Figures 12(a) and (b) are a top view and a bottom view of the antenna device 10a3 according to Embodiment 1, Example 3, respectively. In this embodiment, the first notch 14a is formed in a position that overlaps only with the first antenna element 11 of the two antenna elements 12 when the antenna device 10a3 is viewed from above.

[0048] The dimensions of the first notch 14a are 3 mm x 3 mm, and the first notch 14a is formed such that it has a 3 mm first opening 14b at a position that divides one side of the reflector 14 extending in the y-axis direction into a 28 mm portion and an 18 mm portion.

[0049] Figure 13 shows the antenna characteristics of the antenna device 10a3 according to Embodiment 1, Example 3. More specifically, Figure 13(a) is a Smith chart showing the impedance characteristics of the antenna device 10a3 according to Embodiment 1, Example 3, and Figure 13(b) shows the VSWR characteristics of the antenna device 10a3 according to Embodiment 1, Example 3.

[0050] As can be seen from Figure 13(a), the antenna device 10a3 according to Embodiment 3 of Embodiment 1 is resonating at the operating frequency (2.45 GHz). Furthermore, a kink is observed in the impedance characteristics, which is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the 28 mm long reflector 14 separated by the first notch 14a and the radiator 13.

[0051] Furthermore, as can be seen from Figure 13(b), the antenna device 10a3 according to Embodiment 3 of Embodiment 1 has a bandwidth of 540 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 13(a).

[0052] As described above, the antenna device 10a according to Embodiment 1 is a directional antenna device used in connection with a power supply unit, and comprises a radiator 13 having a plate-shaped first antenna element 11 that has width in the x-axis direction and extends in the y-axis direction, and a second antenna element 12 that is arranged on the same plane as the first antenna element 11, has a smaller width than the first antenna element 11, and has one side 12a that is connected to one side 11a of the first antenna element 11 via a power supply unit, and a plate-shaped, unpowered reflector 14 that is arranged in a plane opposite to the radiator 13, has width in the x-axis direction and extends in the y-axis direction. The reflector 14 has a first notch 14a with a first opening 14b on the first side 141 extending in the y-axis direction of the reflector 14, the reflector 14 is longer than the radiator 13, the second antenna element 12 is shorter than 1 / 4 of the wavelength of the operating frequency, the radiator 13 and the reflector 14 are spaced apart to allow electromagnetic coupling, the resistance component of the input impedance of the antenna device 10a is adjusted by the length of the first antenna element 11, and the reactance component of the input impedance of the antenna device 10a is adjusted by the length of the second antenna element 12.

[0053] Furthermore, since the antenna device 10a according to Embodiment 1 is based on the antenna device 9b according to the Second Reference Example, one side 12a of the second antenna element 12 faces the end of one side 11a of the first antenna element 11 (the first end 11b).

[0054] As a result, the antenna device 10a according to Embodiment 1 is based on the antenna device 9b according to the second reference example, and since a notch is provided in the reflector 14, a kink occurs in the antenna characteristics, resulting in a wider bandwidth than the antenna device 9b according to the second reference example.

[0055] Here, the position of the first notch 14a may be such that, as in Embodiment 1, the first notch 14a overlaps only with the second antenna element 12 of the first antenna element 11 when the antenna device 10a is viewed from above; as in Embodiment 2, the first notch 14a overlaps with the first antenna element 11 and the second antenna element 12 when the antenna device 10a is viewed from above; or as in Embodiment 3, the first notch 14a overlaps only with the first antenna element 11 of the first antenna element 11 and the second antenna element 12 when the antenna device 10a is viewed from above.

[0056] In Embodiment 1, the shape of the first notch 14a was a 3mm square, but it is not limited to this shape and dimensions. Any notch having a first opening 14b on the first side 141 extending in the y-axis direction of the reflector 14 may be a rectangle extending in the x-axis direction, a rectangle extending in the y-axis direction, a notch with a part of a circle or ellipse cut off, or a notch with a shape that is cut in the x-axis direction by a different dimension (longer or shorter) than the width of the first opening 14b.

[0057] In short, the first notch 14a can have any shape and dimensions as long as it forms a section of the reflector 14 that is connected in the y-axis direction and a section that is divided in the y-axis direction.

[0058] (Embodiment 2) Next, as Embodiment 2, we will describe an antenna device based on a different antenna device from the antenna device 9b of the second reference example on which Embodiment 1 was based, and in which a single notch is provided in the reflector 14. Hereinafter, specific examples of the antenna device according to Embodiment 2 will be described as Examples 1 and 2 of Embodiment 2.

[0059] (Example 1 of Embodiment 2) Figure 14 is an external view showing the structure of the antenna device 10b1 according to Embodiment 1 of Embodiment 2. More specifically, (a1) and (a2) in Figure 14 are a perspective view of the antenna device 10b1 according to Embodiment 1 of Embodiment 2, viewed from above and from below, respectively.

[0060] The antenna device 10b1 according to this embodiment is based on the antenna device 9a according to the first reference example. The positional relationship between the first antenna element 11 and the second antenna element 12 is the same as that of the antenna device 9a according to the first reference example, and one side 12a of the second antenna element 12 faces the center of one side 11a of the first antenna element 11. Unless otherwise specified, the dimensions are the same as those of the antenna device 9a according to the first reference example.

[0061] In this embodiment, the first notch 14a is formed in a position that overlaps with the first antenna element 11 and the second antenna element 12 when the antenna device 10b1 is viewed from above, similar to Embodiment 2 of Embodiment 1. The dimensions and position of the first notch 14a are also the same as in Embodiment 2 of Embodiment 1.

[0062] Figure 15 shows the antenna characteristics of the antenna device 10b1 according to Embodiment 2, Example 1. More specifically, Figure 15(a) is a Smith chart showing the impedance characteristics of the antenna device 10b1 according to Embodiment 2, Example 1, and Figure 15(b) shows the VSWR characteristics of the antenna device 10b1 according to Embodiment 2, Example 1.

[0063] As can be seen from Figure 15(a), the antenna device 10b1 according to Embodiment 1 of Embodiment 2 is resonant at the operating frequency (2.45 GHz). Furthermore, in the impedance characteristics, a kink is observed, similar to Embodiment 1. This is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the long portion of the reflector 14 separated by the first notch 14a and the radiator 13, similar to Embodiment 1.

[0064] Furthermore, as can be seen from Figure 15(b), the antenna device 10b1 according to Embodiment 1 of Embodiment 2 has a bandwidth of 540 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9a according to the first reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 15(a).

[0065] (Example 2 of Embodiment 2) Figure 16 is an external view showing the structure of the antenna device 10b2 according to Embodiment 2 of Embodiment 2. More specifically, (a1) and (a2) in Figure 16 are a perspective view of the antenna device 10b2 according to Embodiment 2 of Embodiment 2, viewed from above and from below, respectively.

[0066] The antenna device 10b2 according to this embodiment has a radiator 13 structure that differs from both the antenna device 9a according to the first reference example and the antenna device 9b according to the second reference example. The positional relationship between the first antenna element 11 and the second antenna element 12 is such that one side 12a of the second antenna element 12 faces the second end 11c of one side 11a of the first antenna element 11, which is opposite to the first end 11b. In other words, the structure of the radiator 13 corresponds to the structure of the radiator 13 of the antenna device 9b according to the second reference example, rotated 180 degrees in the x-axis direction. Unless otherwise specified, the dimensions are the same as those of Embodiment 1 of Embodiment 2.

[0067] In this embodiment, the first notch 14a is formed in a position that overlaps only with the first antenna element 11 of the two antenna elements 12 when the antenna device 10b2 is viewed from above.

[0068] Figure 17 shows the antenna characteristics of the antenna device 10b2 according to Embodiment 2 of Embodiment 2. More specifically, Figure 17(a) is a Smith chart showing the impedance characteristics of the antenna device 10b2 according to Embodiment 2 of Embodiment 2, and Figure 17(b) shows the VSWR characteristics of the antenna device 10b2 according to Embodiment 2 of Embodiment 2.

[0069] As can be seen from Figure 17(a), the antenna device 10b2 according to Embodiment 2 of Embodiment 2 is resonant at the operating frequency (2.45 GHz). Furthermore, in the impedance characteristics, a kink is observed, similar to Embodiment 1 of Embodiment 2. This is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the long portion of the reflector 14 separated by the first notch 14a and the radiator 13, similar to Embodiment 1 of Embodiment 2.

[0070] Furthermore, as can be seen from Figure 17(b), the antenna device 10b2 according to Embodiment 2 of Embodiment 2 has a bandwidth of 520 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the antenna device 9a according to the first reference example and the antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 17(a).

[0071] As described above, the antenna devices 10b1 and 10b2 according to Embodiment 2 are directional antenna devices used in connection with a power supply unit, and include a radiator 13 having a plate-shaped first antenna element 11 that has width in the x-axis direction and extends in the y-axis direction, and a second antenna element 12 that is arranged on the same plane as the first antenna element 11, has a smaller width than the first antenna element 11, and has one side 12a that is connected to one side 11a of the first antenna element 11 via a power supply unit, and a plate-shaped, unpowered antenna arranged in the plane opposite to the radiator 13, with width in the x-axis direction and extending in the y-axis direction. The antenna device comprises a radiator plate 14, the reflector plate 14 having a first notch 14a with a first opening 14b on a first side 141 extending in the y-axis direction of the reflector plate 14, the reflector plate 14 being longer than the radiator plate 13, the second antenna element 12 being shorter than 1 / 4 of the wavelength of the operating frequency, the radiator plate 13 and the reflector plate 14 being separated by an electromagnetic coupling distance, the resistive component of the input impedance of the antenna device being adjusted by the length of the first antenna element 11, and the reactance component of the input impedance of the antenna device being adjusted by the length of the second antenna element 12.

[0072] In this embodiment 1, the antenna device 10b1 is located such that one side 12a of the second antenna element 12 faces the center of one side 11a of the first antenna element 11. In this embodiment 1, the first notch 14a is formed in a position that overlaps with the first antenna element 11 and the second antenna element 12 when the antenna device 10b1 is viewed from above.

[0073] Furthermore, in the antenna device 10b2 according to Embodiment 2 of Embodiment 2, one side 12a of the second antenna element 12 faces the end of one side 11a of the first antenna element 11 (the second end 11c opposite to the first end 11b). In this Embodiment 2, the first notch 14a is formed in a position that overlaps only with the first antenna element 11 of the two antenna elements 12 when the antenna device 10b2 is viewed from above.

[0074] In either embodiment, the antenna devices 10b1 and 10b2 according to Embodiment 2 differ from both the antenna device 9a according to the First Reference Example and the antenna device 9b according to the Second Reference Example in that a notch is provided in the reflector 14, resulting in a kink in the antenna characteristics and a wider bandwidth than the antenna device 9a according to the First Reference Example and the antenna device 9b according to the Second Reference Example.

[0075] (Embodiment 3) Next, as Embodiment 3, an antenna device in which two notches are provided in the reflector 14 will be described. Hereinafter, specific examples of the antenna device according to Embodiment 3 will be described as Examples 1 to 3 of Embodiment 3.

[0076] (Example 1 of Embodiment 3) Figure 18 is an external view showing the structure of the antenna device 10c1 according to Embodiment 1 of Embodiment 3. More specifically, Figures 18(a) and (b) are a top view and a bottom view of the antenna device 10c1 according to Embodiment 1 of Embodiment 3, respectively.

[0077] In the antenna device 10c1 according to this embodiment, the reflector 14 has a first notch 14a having a first opening 14b on the first side 141 extending in the y-axis direction of the reflector 14, as well as a second notch 14c having a second opening 14d on the first side 141 extending in the y-axis direction of the reflector 14.

[0078] The first notch 14a and the second notch 14c are formed 3 mm apart in the y-axis direction, and the two notches (first notch 14a and second notch 14c) divide one side of the reflector 14 extending in the y-axis direction into a 28 mm section and a 12 mm section.

[0079] In this embodiment, the first notch 14a is formed in a position that overlaps only with the second antenna element 12 of the first antenna element 11 when the antenna device 10c1 is viewed from above, while the second notch 14c is formed in a position that overlaps only with the first antenna element 11 of the first antenna element 11 of the second antenna element 12 when the antenna device 10c1 is viewed from above.

[0080] Furthermore, since the antenna device 10c1 according to this embodiment is based on the antenna device 9b according to the second reference example, the positional relationship between the first antenna element 11 and the second antenna element 12 is the same as that of the antenna device 9b according to the second reference example, with one side 12a of the second antenna element 12 facing the first end 11b of one side 11a of the first antenna element 11. In addition, the dimensions are the same as those of the antenna device 9b according to the second reference example unless otherwise specified.

[0081] Figure 19 shows the antenna characteristics of the antenna device 10c1 according to Embodiment 1 of Embodiment 3. More specifically, Figure 19(a) is a Smith chart showing the impedance characteristics of the antenna device 10c1 according to Embodiment 1 of Embodiment 3, and Figure 19(b) shows the VSWR characteristics of the antenna device 10c1 according to Embodiment 1 of Embodiment 3.

[0082] As can be seen from Figure 19(a), the antenna device 10c1 according to Embodiment 1 of Embodiment 3 is resonant at the operating frequency (2.45 GHz). Furthermore, in the impedance characteristics, a kink is observed, similar to Embodiments 1 and 2. This is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the long portion of the reflector 14, which is divided by the two notches (first notch 14a and second notch 14c), and the radiator 13, similar to Embodiments 1 and 2.

[0083] Furthermore, as can be seen from Figure 19(b), the antenna device 10c1 according to Embodiment 1 of Embodiment 3 has a bandwidth of 600 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 19(a).

[0084] (Example 2 of Embodiment 3) Figure 20 is an external view showing the structure of the antenna device 10c2 according to Embodiment 2 of Embodiment 3. More specifically, Figures 20(a) and (b) are the top view and bottom view of the antenna device 10c2 according to Embodiment 2 of Embodiment 3, respectively.

[0085] In the antenna device 10c2 according to this embodiment, the reflector 14 has a first notch 14a having a first opening 14b on the first side 141 extending in the y-axis direction of the reflector 14, as well as a second notch 14c having a second opening 14d on the second side 142 opposite to the first side 141 extending in the y-axis direction of the reflector 14.

[0086] The first notch 14a and the second notch 14c are formed 3 mm apart in the y-axis direction, similar to Embodiment 1 of Embodiment 3, and the two notches (first notch 14a and second notch 14c) divide one side of the reflector 14 extending in the y-axis direction into a 28 mm portion and a 12 mm portion.

[0087] In this embodiment, the first notch 14a is formed in a position that overlaps only with the second antenna element 12 of the first antenna element 11 when the antenna device 10c2 is viewed from above, while the second notch 14c is formed in a position that overlaps only with the first antenna element 11 of the first antenna element 11 of the second antenna element 12 when the antenna device 10c2 is viewed from above.

[0088] Furthermore, since the antenna device 10c2 according to this embodiment is based on the antenna device 9b according to the second reference example, the positional relationship between the first antenna element 11 and the second antenna element 12 is the same as that of the antenna device 9b according to the second reference example, with one side 12a of the second antenna element 12 facing the first end 11b of one side 11a of the first antenna element 11. In addition, the dimensions are the same as those of the antenna device 9b according to the second reference example unless otherwise specified.

[0089] Figure 21 shows the antenna characteristics of the antenna device 10c2 according to Embodiment 3, Example 2. More specifically, Figure 21(a) is a Smith chart showing the impedance characteristics of the antenna device 10c2 according to Embodiment 3, Example 2, and Figure 21(b) shows the VSWR characteristics of the antenna device 10c2 according to Embodiment 3, Example 2.

[0090] As can be seen from Figure 21(a), the antenna device 10c2 according to Embodiment 2 of Embodiment 3 is resonant at the operating frequency (2.45 GHz). Furthermore, in the impedance characteristics, a kink is observed, similar to Embodiment 1 of Embodiment 3. This is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the long portion of the reflector 14, which is divided by the two notches (first notch 14a and second notch 14c), and the radiator 13, similar to Embodiment 1 of Embodiment 3.

[0091] Furthermore, as can be seen from Figure 21(b), the antenna device 10c2 according to Embodiment 2 of Embodiment 3 has a bandwidth of 600 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 21(a).

[0092] (Example 3 of Embodiment 3) Figure 22 is an external view showing the structure of the antenna device 10c3 according to Embodiment 3 of Embodiment 3. More specifically, Figures 22(a) and (b) are the top view and bottom view of the antenna device 10c3 according to Embodiment 3 of Embodiment 3, respectively.

[0093] In the antenna device 10c3 according to this embodiment, the reflector 14 has a first notch 14a having a first opening 14b on the first side 141 extending in the y-axis direction of the reflector 14, as well as a second notch 14c having a second opening 14d on the second side 142 opposite to the first side 141 extending in the y-axis direction of the reflector 14.

[0094] The first notch 14a and the second notch 14c are formed at the same position in the y-axis direction, and the two notches (first notch 14a and second notch 14c) divide one side of the reflector 14 extending in the y-axis direction into a 31 mm section and a 15 mm section.

[0095] In this embodiment, the first notch 14a is formed in a position that overlaps with the first antenna element 11 and the second antenna element 12 when the antenna device 10c3 is viewed from above, while the second notch 14c is formed in a position that overlaps with only the first antenna element 11 of the two antenna elements 12 when the antenna device 10c3 is viewed from above.

[0096] Furthermore, since the antenna device 10c3 according to this embodiment is based on the antenna device 9b according to the second reference example, the positional relationship between the first antenna element 11 and the second antenna element 12 is the same as that of the antenna device 9b according to the second reference example, with one side 12a of the second antenna element 12 facing the first end 11b of one side 11a of the first antenna element 11. In addition, the dimensions are the same as those of the antenna device 9b according to the second reference example unless otherwise specified.

[0097] Figure 23 shows the antenna characteristics of the antenna device 10c3 according to Embodiment 3 of Embodiment 3. More specifically, Figure 23(a) is a Smith chart showing the impedance characteristics of the antenna device 10c3 according to Embodiment 3 of Embodiment 3, and Figure 23(b) shows the VSWR characteristics of the antenna device 10c3 according to Embodiment 3 of Embodiment 3.

[0098] As can be seen from Figure 23(a), the antenna device 10c3 according to Embodiment 3 of Embodiment 3 is resonant at the operating frequency (2.45 GHz). Furthermore, in the impedance characteristics, a kink is observed, similar to Embodiments 1 and 2 of Embodiment 3. This is thought to be due to the coupling between the entire reflector 14 and the radiator 13, as well as the coupling between the long portion of the reflector 14, which is divided by the two notches (first notch 14a and second notch 14c), and the radiator 13, similar to Embodiments 1 and 2 of Embodiment 3.

[0099] Furthermore, as can be seen from Figure 23(b), the antenna device 10c3 according to Embodiment 3 of Embodiment 3 has a bandwidth of 580 MHz for VSWR ≤ 2, which is wider than the bandwidth (420 MHz) of the base antenna device 9b according to the second reference example. This is thought to be due to the effect of a kink that occurred in the impedance characteristics shown in Figure 23(a).

[0100] As described above, the antenna devices 10c1 to 10c3 according to Embodiment 3 are directional antenna devices used in connection with a power supply unit, and include a radiator 13 having a plate-shaped first antenna element 11 that has width in the x-axis direction and extends in the y-axis direction, and a second antenna element 12 that is arranged on the same plane as the first antenna element 11, has a smaller width than the first antenna element 11, and has one side 12a that is connected to one side 11a of the first antenna element 11 via a power supply unit, and a plate-shaped, unpowered antenna arranged in the plane opposite to the radiator 13, with width in the x-axis direction and extending in the y-axis direction. The antenna device comprises a radiator plate 14, the reflector plate 14 having a first notch 14a with a first opening 14b on a first side 141 extending in the y-axis direction of the reflector plate 14, the reflector plate 14 being longer than the radiator plate 13, the second antenna element 12 being shorter than 1 / 4 of the wavelength of the operating frequency, the radiator plate 13 and the reflector plate 14 being separated by an electromagnetic coupling distance, the resistive component of the input impedance of the antenna device being adjusted by the length of the first antenna element 11, and the reactance component of the input impedance of the antenna device being adjusted by the length of the second antenna element 12.

[0101] Furthermore, the reflector 14 has a second notch 14c formed on the second side 142 extending in the y-axis direction of the reflector 14, which has a second opening 14d.

[0102] Here, regarding the positions of the two notches (first notch 14a and second notch 14c), the first side 141 and the second side 142 on which the respective openings are formed may be the same side, as in Example 1, or they may be different sides, as in Examples 2 and 3. Furthermore, as in Example 3, the first notch 14a and the second notch 14c may be formed at the same position in the y-axis direction, that is, at positions aligned in the x-axis direction.

[0103] In any of the embodiments, the antenna devices 10c1 to 10c3 according to Embodiment 3 are based on the antenna device 9b according to the second reference example, and since the reflector 14 has two notches, a kink occurs in the antenna characteristics, resulting in a wider bandwidth than the antenna device 9b according to the second reference example.

[0104] The antenna devices 10c1 to 10c3 according to Embodiment 3 are based on the antenna device 9b according to the Second Reference Example, but are not limited to this. They may also be antenna devices based on the antenna device 9a according to the First Reference Example, the antenna device 10b1 according to Example 1 of Embodiment 2, or the antenna device 10b2 according to Example 2 of Embodiment 2, with two notches provided in the reflector 14.

[0105] Furthermore, in the antenna devices 10c1 to 10c3 according to Embodiment 3, two notches are provided in the reflector 14, but three or more notches may be provided.

[0106] (Embodiment 4) Next, as Embodiment 4, we will describe an antenna device in which a through-hole is provided in the notched area of ​​Embodiments 1 to 3.

[0107] Figure 24 is an external view showing the structure of the antenna device 10d according to Embodiment 4. A bottom view of the antenna device 10d according to Embodiment 4 is shown here. A first notch 14a is formed in the reflector 14, and through holes 15a and 15b are formed in the area of ​​the first notch 14a. This embodiment can be applied to the antenna device 10a2 according to Embodiment 1, Example 2, the antenna device 10b1 according to Embodiment 2, Example 1, and the antenna device 10c3 according to Embodiment 3, Example 3.

[0108] The first notch 14a formed in the reflector 14 coincides with the "feed point," which is the gap between one side 11a of the first antenna element 11 and one side 12a of the second antenna element 12, when viewed from above, and is connected to the feed point (not shown).

[0109] The antenna device 10d according to this embodiment includes a substrate 15 on which a radiator 13 is formed on the upper surface and a reflector 14 is formed on the lower surface. In the region of the first cutout 14a of the substrate 15, a through-hole 15a connected to the first antenna element 11 and a through-hole 15b connected to the second antenna element 12 are formed.

[0110] These through-holes 15a and 15b allow power to be supplied from the bottom surface of the substrate 15 of the antenna device 10d to the first antenna element 11 and the second antenna element 12, increasing the flexibility of mounting the antenna device 10d onto equipment.

[0111] The antenna devices relating to this disclosure have been described above based on Embodiments 1 to 4, but this disclosure is not limited to these Embodiments 1 to 4. As long as they do not depart from the spirit of this disclosure, various modifications that a person skilled in the art can conceive of Embodiments 1 to 4, as well as other forms constructed by combining some of the components of Embodiments 1 to 4, are also included within the scope of this disclosure.

[0112] For example, in the antenna devices according to Embodiments 1 to 4, a radiator 13 and a reflector 14 are formed on the upper and lower surfaces of a single substrate 15, respectively. However, the device is not limited to such a single substrate configuration. In order to meet the constraint that there is a distance between the radiator 13 and the reflector 14 that allows for electromagnetic coupling, the radiator 13 and the reflector 14 may be formed on different substrates.

[0113] Furthermore, in the antenna device 10c2 according to Embodiment 2 of Embodiment 3, one notch is provided on each of the first side 141 and the second side 142 of the reflector 14. However, it is not necessarily required that the same number of notches be provided on each side. For example, one notch may be provided on the first side 141 and two notches on the second side 142. [Industrial applicability]

[0114] The antenna device described herein is a broadband antenna device with directional properties and a miniaturizable structure, and can be used, for example, as an antenna device for in-vehicle infotainment systems, wearable devices, mobile devices, and the like. [Explanation of symbols]

[0115] 10a, 10a1, 10a2, 10a3, 10b1, 10b2, 10c1, 10c2, 10c3, 10d Antenna equipment 11. First antenna elements 11a One side of the first antenna element 11b The first end of one side of the first antenna element 11c The second end of one side of the first antenna element 12. Second antenna element 12a One side of the second antenna element 13. Radiator 14 Reflector 14a First notch formed in the reflector 14b First opening of the first notch formed in the reflector 14c Second notch formed in the reflector 14d Second opening of the second notch formed in the reflector 141 The first side of the reflector 142 The second side of the reflector 15 circuit boards 15a, 15b Through-hole

Claims

1. A directional antenna device used in connection with a power supply unit, A radiator comprising a plate-shaped first antenna element having a width in a first direction and extending in a second direction perpendicular to the first direction, and a second antenna element arranged on the same plane as the first antenna element, having a smaller width than the first antenna element and having one side connected to one side of the first antenna element via the power supply section, The device comprises a reflector that is arranged in a plane opposite to the radiator, has a width in the first direction and extends in the second direction, is plate-shaped, and is unpowered, The reflector has a first notch formed on the first side of the reflector that extends in the second direction, having a first opening. The reflector has a longer length than the radiator, The second antenna element has a length shorter than 1 / 4 of the wavelength of the operating frequency. The radiator and the reflector are spaced apart so that they can be electromagnetically coupled. The resistive component of the input impedance of the antenna device is adjusted by the length of the first antenna element. The reactance component of the input impedance of the antenna device is adjusted by the length of the second antenna element. The first notch is formed in a position that overlaps with at least one of the first antenna element and the second antenna element when the antenna device is viewed in plan. Antenna device.

2. The first notch is formed in a position that overlaps only with the second antenna element of the first antenna element when the antenna device is viewed in plan. The antenna device according to claim 1.

3. The first notch is formed in a position that overlaps with the first antenna element and the second antenna element when the antenna device is viewed in plan. The antenna device according to claim 1.

4. The first notch is formed in a position that overlaps only with the first antenna element among the first and second antenna elements when the antenna device is viewed from above. The antenna device according to claim 1.

5. The side of the second antenna element faces the end of the side of the first antenna element. The antenna device according to any one of claims 1 to 4.

6. The side of the second antenna element faces the central part of the side of the first antenna element. The antenna device according to any one of claims 1 to 4.

7. The reflector further has a second notch formed on the second side of the reflector that extends in the second direction, having a second opening. The antenna device according to any one of claims 1 to 4.

8. The first side and the second side are the same side. The antenna device according to claim 7.

9. The first side and the second side are different sides. The antenna device according to claim 7.

10. The first notch and the second notch are formed in positions aligned in the first direction. The antenna device according to claim 9.

11. Furthermore, the substrate comprises a radiator formed on its upper surface and a reflector formed on its lower surface, The region of the first notch in the substrate has through-holes formed therein that connect to the first antenna element and through-holes formed therein that connect to the second antenna element. The antenna device according to claim 3.

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