Antenna device and wireless communication device having the same

Abstract

The antenna device includes: a feed point; a first antenna conductor extending from the feed point and increasing in width as it moves away from the feed point; a second antenna conductor facing the top edge of the first antenna conductor with a gap therebetween; a first connection portion connecting the top edge of the first antenna conductor and the second antenna conductor via a capacitor; and a second connection portion connecting the top edge of the first antenna conductor and the second antenna conductor via an inductor or a zero-ohm resistor. A first connection point where the first connection portion is connected to the first antenna conductor is closer to the center of the top edge of the first antenna conductor than a second connection point where the second connection portion is connected to the first antenna conductor.

Description

Technical Field

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

[0002] For example, Patent Document 1 discloses a miniaturized bowtie antenna that maintains broadband characteristics. The bowtie antenna has broadband characteristics because a pair of antenna conductors each extend away from a feed point and have a shape that increases in width as they move away from the feed point.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2010-263524 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] In addition, a miniaturized antenna device that communicates in a wide-band first frequency band is required to be usable in another second frequency band, that is, to be capable of dual-band communication. However, when the second frequency band is a lower frequency band than the first frequency band, the antenna length needs to be extended in order to communicate with the second frequency band. As a result, the antenna device becomes larger.

[0008] Therefore, an object of the present invention is to enable an antenna device that communicates in a high frequency band of a wide frequency band to communicate in a low frequency band while suppressing an increase in size.

[0009] Solutions for solving problems

[0010] In order to solve the above technical problems, according to one embodiment of the present invention, an antenna device is provided, wherein the antenna device comprises: a feed point; a first antenna conductor extending from the feed point in a direction away from the ground conductor, and the width thereof becomes wider as it moves away from the feed point; a second antenna conductor opposite to the top edge of the first antenna conductor with a gap therebetween; a first connecting portion connecting the top edge of the first antenna conductor and the second antenna conductor via a capacitor; and a second connecting portion connecting the top edge of the first antenna conductor and the second antenna conductor via an inductor or a zero-ohm resistor, wherein a first connecting point where the first connecting portion is connected to the first antenna conductor is closer to the center of the top edge of the first antenna conductor than a second connecting point where the second connecting portion is connected to the first antenna conductor.

[0011] Furthermore, according to a different aspect of the present invention, a wireless communication device is provided, wherein the wireless communication device includes: the above-mentioned antenna device; and a power supply circuit that supplies power to a power supply point of the antenna device.

[0012] Effects of the Invention

[0013] According to the present invention, an antenna device that communicates in a high frequency band of a wide frequency band can also communicate in a low frequency band while suppressing an increase in size. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a plan view of a wireless communication device including the antenna apparatus according to the first embodiment of the present invention.

[0015] Figure 2 This is a partial enlarged view of a wireless communication device.

[0016] Figure 3 It is a partially enlarged view of a wireless communication device including an antenna apparatus according to a comparative example.

[0017] Figure 4 It is a diagram showing the frequency characteristics (matching completed) of the return loss of the antenna device according to Embodiment 1 (Example 1) and the antenna device according to the comparative example.

[0018] Figure 5 This is a partially enlarged view of a wireless communication device including an antenna device according to Embodiment 2 of the present invention.

[0019] Figure 6 It is a diagram showing the frequency characteristics (matching completed) of the return loss of the antenna device according to the first embodiment (Example 1) and the antenna device according to the second embodiment (Example 2).

[0020] Figure 7 This is a partially enlarged view of a wireless communication device including an antenna apparatus according to a third embodiment of the present invention.

[0021] Figure 8 This is a diagram showing the relationship between the inductance value of the inductor arranged between the short-circuit conductor and the ground conductor and between the short-circuit conductor and the first antenna conductor and the bandwidth of the frequency band.

[0022] Fig. 9 This is a partially enlarged view of a wireless communication device including an antenna device according to a fourth embodiment of the present invention.

[0023] Fig.10 This is a partially enlarged view of a wireless communication device including an antenna device according to a fifth embodiment of the present invention.

[0024] Fig.11This is a partially enlarged view of a wireless communication device including an antenna device according to a sixth embodiment of the present invention.

[0025] Fig.12 This is a partially enlarged view of a wireless communication device including an antenna device according to Embodiment 7 of the present invention.

[0026] Fig.13 This is a partially enlarged view of a wireless communication device including an antenna device according to Embodiment 8 of the present invention.

[0027] Fig.14 This is a partially enlarged view of a wireless communication device including an antenna device according to Embodiment 9 of the present invention.

[0028] Fig.15 This is a partially enlarged view of a wireless communication device including the antenna device according to Embodiment 10 of the present invention. DETAILED DESCRIPTION

[0029] An antenna device according to one embodiment of the present invention comprises: a power supply point; a first antenna conductor extending from the power supply point in a direction away from the ground conductor, and having a width that becomes wider as it moves away from the power supply point; a second antenna conductor that is spaced apart from the top edge of the first antenna conductor and faces the second antenna conductor; a first connecting portion that connects the top edge of the first antenna conductor and the second antenna conductor via a capacitor; and a second connecting portion that connects the top edge of the first antenna conductor and the second antenna conductor via an inductor or a zero-ohm resistor, wherein a first connecting point where the first connecting portion is connected to the first antenna conductor is closer to the center of the top edge of the first antenna conductor than a second connecting point where the second connecting portion is connected to the first antenna conductor.

[0030] According to such an aspect, an antenna device that communicates in a high frequency band of a wide frequency band can also communicate in a low frequency band while suppressing an increase in size.

[0031] For example, the first connection point may be located at the center of the distal end edge of the first antenna conductor, or the second connection point may be located at one end of the distal end edge of the first antenna conductor.

[0032] For example, the antenna device may further include a ground conductor connected to the feed point. In this case, the first antenna conductor extends in a direction away from the ground conductor.

[0033] For example, the antenna device may further include a short-circuit conductor, one end of which is connected to the first antenna conductor, and the other end of which is connected to the ground conductor. In this case, preferably, a third connection point where the short-circuit conductor is connected to the first antenna conductor is closer to the second connection point than the first connection point.

[0034] For example, one end of the short-circuit conductor may be connected to the first antenna conductor via an inductor, and the other end of the short-circuit conductor may be connected to the ground conductor via an inductor.

[0035] For example, the width of the second antenna conductor may be equal to or larger than the length of the distal edge.

[0036] For example, the first antenna conductor may be in a triangular shape with the top edge as the base, or the second antenna conductor may be in a rectangular shape.

[0037] For example, the first antenna conductor may be in a triangular shape with two oblique sides having different lengths.

[0038] A wireless communication device according to another aspect of the present invention includes: the antenna device described above; and a power supply circuit that supplies power to a power supply point of the antenna device.

[0039] According to such an aspect, an antenna device that communicates in a high frequency band of a wide frequency band can also communicate in a low frequency band while suppressing an increase in size.

[0040] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0041] (Implementation Method 1)

[0042] Figure 1 : is a top view of a wireless communication device including the antenna device according to Embodiment 1 of the present invention. Figure 2 1 is a partial enlarged view of a wireless communication device. In addition, the XYZ rectangular coordinate system shown in the figure is used to facilitate understanding of the present invention and does not limit the present invention. In addition, in this specification, the X-axis direction is the width direction and the Y-axis direction is the length direction.

[0043] like Figure 1 As shown, the wireless communication device 50 having the antenna device 10 of the first embodiment is mounted on an electronic device capable of wireless communication for use. In addition, the antenna device 10 is an antenna device for dual frequencies capable of communication at a relatively high frequency band (HB band) and a relatively low frequency band (LB band). In the case of the first embodiment, the higher frequency band is the 5 GHz band (e.g., 5.15 to 5.85 GHz), and the lower frequency band is the 2.4 GHz band (e.g., 2.4 to 2.484 GHz). In addition, the higher frequency band is a wider frequency band than the lower frequency band.

[0044] like Figure 1As shown, in the case of the present embodiment 1, the antenna device 10 has: a ground conductor 12, which is provided on the base substrate 52 of the wireless communication device 50; a first antenna conductor 14 and a second antenna conductor 16, which are provided on the base substrate 52 and connected to the ground conductor 12; and a first connecting portion 18 and a second connecting portion 20, which connect the first antenna conductor 14 and the second antenna conductor 16.

[0045] In the case of the first embodiment, the antenna device 10 includes a power supply point 22 and a matching circuit 24 provided between the ground conductor 12 and the first antenna conductor 14. In addition, a power supply circuit (not shown) provided in the wireless communication device 50 is connected to the power supply point 22. The antenna device 10 is powered from the power supply circuit via the power supply point 22. In addition, the matching circuit 24 is, for example, an LC resonant circuit including a chip inductor and a chip capacitor.

[0046] In the case of the first embodiment, the ground conductor 12 of the antenna device 10 has a rectangular shape and is a conductor pattern made of, for example, copper, formed on a base substrate 52 made of an insulating material.

[0047] In the case of the first embodiment, the first antenna conductor 14 and the second antenna conductor 16 of the antenna device 10 are conductor patterns made of, for example, copper, formed on the base substrate 52 .

[0048] The first antenna conductor 14 has a shape that extends from the power feeding point 22 in a direction (Y-axis direction) away from the ground conductor 12 and has a width (dimension in the X-axis direction) that increases as it moves away from the power feeding point 22 .

[0049] Specifically, the first antenna conductor 14 extends from the feed point 22 in the length direction (Y-axis direction) in a manner away from the end edge 12a of the ground conductor 12 provided with the feed point 22. In addition, as it moves away from the feed point 22, that is, as it approaches the edge of the distal end farther from the feed point 22, that is, the top edge 14a, the width (dimension in the X-axis direction) becomes wider linearly. In the case of the first embodiment, the first antenna conductor 14 has a triangular shape with the top edge 14a as the base and the remaining two oblique sides 14b and 14c of different lengths. In addition, the top edge 14a of the first antenna conductor 14 is linear and extends in the width direction (X-axis direction) in a state parallel to the end edge 12a of the ground conductor 12.

[0050] The second antenna conductor 16 is provided so as to face the distal end edge 14 a of the first antenna conductor 14 with a gap therebetween.

[0051] Specifically, the second antenna conductor 16 is disposed opposite to the top edge 14a of the first antenna conductor 14 at a distance in the longitudinal direction (Y-axis direction). In the first embodiment, the second antenna conductor 16 has a rectangular shape extending in the longitudinal direction (Y-axis direction) while maintaining a width (dimension in the X-axis direction) equal to the length of the top edge 14a of the first antenna conductor 14. The length (dimension in the Y-axis direction) of the second antenna conductor 16 in the rectangular shape is smaller than the width (dimension in the X-axis direction).

[0052] First connection portion 18 connects first antenna conductor 14 and second antenna conductor 16 via a capacitor. In the case of the first embodiment, first connection portion 18 connects first antenna conductor 14 and second antenna conductor 16 via chip capacitor 26 having a desired capacitance. In place of chip capacitor 26, a capacitor may be formed using a gap between a protrusion protruding from first antenna conductor 14 toward second antenna conductor 16 and a protrusion protruding from second antenna conductor 16 toward first antenna conductor 14.

[0053] The second connection portion 20 connects the first antenna conductor 14 and the second antenna conductor 16 via an inductor. In the case of the first embodiment, the second connection portion 20 connects the first antenna conductor 14 and the second antenna conductor 16 via a chip inductor 28 having a desired inductance. In addition, instead of the chip inductor 28, the first antenna conductor 14 and the second antenna conductor 16 may be connected via a conductor pattern having a shape (e.g., a meandering shape) having a desired inductance. Alternatively, instead of the chip inductor 28, the second connection portion 20 may connect the first antenna conductor 14 and the second antenna conductor 16 via a zero-ohm resistor.

[0054] In addition, the first connecting portion 18 and the second connecting portion 20 are arranged between the first antenna conductor 14 and the second antenna conductor 16 in the following manner: the connection point (first connection point) 18a where the first connecting portion 18 is connected to the first antenna conductor is closer to the center of the top edge 14a of the first antenna conductor 14 than the connection point (second connection point) 20a where the second connecting portion 20 is connected to the first antenna conductor.

[0055] In the first embodiment, connection point 18a between first connection portion 18 and first antenna conductor 14 is located at the center of top edge 14a of first antenna conductor 14. In contrast, connection point 20a between second connection portion 20 and first antenna conductor 14 is located at one end of top edge 14a of first antenna conductor 14.

[0056] According to such antenna device 10, in the case of communication at a relatively high frequency band (5 GHz band), as shown in FIG. Figure 2 As shown, the current I HBThe current flows from the power supply point 22 toward the first connection portion 18 at the center of the width of the first antenna conductor 14, then flows in the first connection portion 18, and then flows in the second antenna conductor 16 along its length direction (Y-axis direction). The reason why this current path is generated is that a relatively high frequency current flows more easily in the capacitor (chip capacitor 26) of the first connection portion 18 than in the inductor (chip inductor 28) of the second connection portion 20. This current I HB The path length is essentially equivalent to 1 / 4 of the wavelength of the higher frequency band.

[0057] On the other hand, in the case of communication at a lower frequency band (2.4 GHz band), the current I LB The current flows from the power supply point 22 toward the second connection portion 20 along the oblique side 14b of the first antenna conductor 14, then flows in the second connection portion 20, and then flows in the second antenna conductor 16 along its width direction (X-axis direction). The reason why this current path is generated is that a relatively low-frequency current easily flows in the inductor (chip inductor 28) of the second connection portion 20 compared to the capacitor (chip capacitor 26) of the first connection portion 18. This current I LB The path length is essentially equivalent to 1 / 4 of the wavelength of the lower frequency band.

[0058] The effect of the antenna device 10 having such a configuration will be described. Table 1 shows the efficiency of the antenna device 10 according to the first embodiment.

[0059] [Table 1]

[0060]

[0061] Table 1 shows the band average efficiency in the frequency band of 2.4 to 2.484 GHz (LB band) and the band average efficiency in the frequency band of 5.15 to 5.85 GHz (HB band) of the antenna device 10 (Example 1) according to the first embodiment.

[0062] like Figure 1 As shown, the arrangement area of ​​the first antenna conductor 14 and the second antenna conductor 16 of the antenna device 10 of the first embodiment is an area with a length L1 of 9.5 mm and a width W1 of 11.5 mm. For reference, the length L2 of the base substrate is 35 mm and the width W2 is 25 mm. In addition, the capacitance of the chip capacitor 26 of the first connecting portion 18 is 0.1 pF, and the inductance of the chip inductor 28 of the second connecting portion 20 is 1.1 nH.

[0063] In addition, for reference, Table 1 shows the band average efficiency in the LB band and the band average efficiency in the HB band of the antenna device of the comparative example.

[0064] Figure 3It is a partially enlarged view of a wireless communication device including an antenna apparatus according to a comparative example.

[0065] like Figure 3 As shown, the antenna device 110 of the wireless communication device 150 of the comparative example has a triangular antenna conductor 114 whose width becomes wider as it moves away from the feed point 122. The installation area of ​​the antenna conductor 114 is substantially the same as the installation area of ​​the first antenna conductor 14 and the second antenna conductor 16 of the antenna device 10 of the first embodiment (Example 1). In addition, the antenna device 110 of the comparative example includes a matching circuit 124 that achieves matching between the feed point 122 and the antenna conductor 114 in the lower frequency band LB and the higher frequency band HB similar to the antenna device 10 of Example 1.

[0066] Figure 4 The frequency characteristics of the return loss of the antenna device according to the first embodiment (Example 1) and the antenna device according to the comparative example (matching completed) are shown.

[0067] like Figure 4 As shown, the antenna device 10 of Example 1 (dashed line) and the antenna device 110 of the comparative example (solid line) achieve matching in the lower frequency band LB and the higher frequency band HB when the return loss is 10 dB or more, which is a practical level.

[0068] As shown in Table 1, the antenna device 110 of the comparative example has a good efficiency with an average efficiency value higher than -1.0 dB (actual level) in the higher frequency band HB, but has an unfavorable average efficiency value of -2.2 dB in the lower frequency band LB.

[0069] On the other hand, in the case of Example 1, the average efficiency of both the higher frequency band HB and the lower frequency band LB is higher than -1.0 dB. Therefore, the antenna device 10 of Example 1 has high and good efficiency in both the higher frequency band HB and the lower frequency band LB.

[0070] Therefore, if the antenna conductor 114 of the comparative example capable of communicating in a higher frequency band of a wide frequency band is divided into the first antenna conductor 14 and the second antenna conductor 16 as in Example 1 and they are connected using the first connecting portion 18 and the second connecting portion 20, good efficiency can be obtained in both the higher frequency band and the lower frequency band without substantially expanding the installation area of ​​the antenna conductor.

[0071] According to the first embodiment as described above, an antenna device that communicates in a high frequency band of a wide frequency band can be made to communicate in a low frequency band while suppressing an increase in size.

[0072] (Implementation Method 2)

[0073] Embodiment 2 is an improved form of Embodiment 1. Therefore, Embodiment 2 will be described mainly with respect to the differences from Embodiment 1. Components of Embodiment 2 that are substantially the same as those of Embodiment 1 are denoted by the same reference numerals.

[0074] Figure 5 This is a partially enlarged view of a wireless communication device including an antenna device according to Embodiment 2 of the present invention.

[0075] like Figure 5 As shown, in the antenna device 210 of the wireless communication device 250 of the second embodiment, the first antenna conductor 14 is connected to the ground conductor 12 via the feed point 22 and is also connected to the ground conductor 12 via the short-circuit conductor 230. That is, the first antenna conductor 14 is short-circuited to the ground conductor 12 via the short-circuit conductor 230.

[0076] Specifically, the short-circuit conductor 230 is a conductor having one end connected to the first antenna conductor 14 and the other end connected to the ground conductor 12. In addition, the connection point (third connection point) 230a where the short-circuit conductor 230 is connected to the first antenna conductor 14 is farther from the connection point (first connection point) 18a where the first connection portion 18 is connected to the first antenna conductor 14, and closer to the connection point (second connection point) 20a where the second connection portion 20 is connected to the first antenna conductor 14. That is, in the case of the second embodiment, the ground conductor 12, the first antenna conductor 14, and the short-circuit conductor 230 are integrated into one component (for example, one conductor pattern). In addition, it is preferable that the connection point 20a and the connection point 230a are close to each other as in the second embodiment.

[0077] Figure 6 The frequency characteristics of the return loss of the antenna device according to the first embodiment (Example 1) and the antenna device according to the second embodiment (Example 2) are shown (matching completed).

[0078] like Figure 6 As shown in FIG. 1 , by providing the short-circuit conductor 230 (Example 2), when the return loss is 10 dB or more above the actual level, the bandwidth of the lower frequency band is expanded to approximately two times. This is because, at the frequency of the lower frequency band, the antenna device 10 of the above-mentioned Embodiment 1 (Example 1) functions as a monopole antenna, whereas the antenna device 210 of the present Embodiment 2 (Example 2) functions as an inverted-F antenna.

[0079] Furthermore, as shown in Table 2, the efficiency does not change significantly even if the bandwidth of the lower frequency band is expanded. In this second embodiment (Example 2), as in the first embodiment (Example 1), good efficiency can be obtained in both the higher frequency band and the lower frequency band.

[0080] [Table 2]

[0081]

[0082] In addition, it is preferred that Figure 5 As shown in FIG. 1 , the short-circuit conductor 230 is arranged to extend along the edge 52a of the base substrate 52 made of an insulating material. With such an arrangement of the short-circuit conductor 230, in the case of a relatively low frequency band, the current easily flows in the portion of the ground conductor 12 along the edge 52a of the base substrate 52. As a result, compared with the case where the short-circuit conductor 230 is provided at a position away from the edge 52a of the base substrate 52, in the relatively low frequency band, its bandwidth is expanded and the efficiency is improved.

[0083] According to the second embodiment as described above, similarly to the first embodiment, an antenna device that communicates in a wide-band high frequency band can communicate in a low frequency band while suppressing an increase in size. In addition, the bandwidth of the low frequency band can be expanded.

[0084] (Implementation 3)

[0085] Embodiment 3 is an improved form of Embodiment 2. Therefore, Embodiment 3 will be described mainly with respect to the differences from Embodiment 2. Components of Embodiment 3 that are substantially the same as those of Embodiment 2 are denoted by the same reference numerals.

[0086] Figure 7 This is a partially enlarged view of a wireless communication device including an antenna apparatus according to a third embodiment of the present invention.

[0087] like Figure 7 As shown, in the antenna device 310 of the wireless communication device 350 of the third embodiment, the first antenna conductor 14 is short-circuited with the ground conductor 12 via the short-circuit conductor 330. However, the short-circuit conductor 330 is another conductor independent of the ground conductor 12 and the first antenna conductor 14. Therefore, one end of the short-circuit conductor 330 is connected to the first antenna conductor 14 via an inductor such as a chip inductor 332, and the other end is also connected to the ground conductor 12 via the chip inductor 332. In the case of the third embodiment, the chip inductor 332 between the short-circuit conductor 330 and the ground conductor 12 and the chip inductor 332 between the short-circuit conductor 330 and the first antenna conductor 14 have the same inductance. In addition, the two chip inductors 332 may have different inductances.

[0088] Figure 8 This is a diagram showing the relationship between the inductance value of the inductor arranged between the short-circuit conductor and the ground conductor and between the short-circuit conductor and the first antenna conductor and the bandwidth of the frequency band.

[0089] like Figure 8 As shown in FIG. 1 , when the inductance of the chip inductor 332 increases, the bandwidth of the higher frequency band (HB band) expands. Therefore, by adjusting the inductance of the chip inductor 332, the higher frequency band can be made to have a desired bandwidth.

[0090] In addition, as an alternative to connection via the chip inductor 332, one end and the other end of the short-circuit conductor 330 can also be changed to a different width from the portion between one end and the other end, that is, it can be formed in a shape with a desired inductance and connected to the ground conductor 12 and the first antenna conductor 14.

[0091] According to the third embodiment as described above, similar to the second embodiment, an antenna device that communicates in a higher frequency band of a wide frequency band can communicate in a lower frequency band while suppressing the size increase. In addition, the bandwidth of the lower frequency band can be expanded. Furthermore, the bandwidth of the higher frequency band can also be expanded.

[0092] As mentioned above, although a plurality of Embodiments 1 to 3 are cited to explain the present invention, the embodiments of the present invention are not limited thereto.

[0093] For example, in the case of the above-mentioned embodiment 1, if Figure 2 As shown, the second antenna conductor 16 is rectangular. Specifically, the second antenna conductor 16 is a rectangular shape extending in the length direction (Y-axis direction) in a state where the width (dimension in the X-axis direction) is constant and the length (dimension in the Y-axis direction) is smaller than the width. In addition, its width is the same size as the length of the top edge 14a of the first antenna conductor 14. However, the embodiment of the present invention does not limit the shape of the second antenna conductor to a rectangular shape.

[0094] Figures 9 to 13 Each of them is a partially enlarged view of a wireless communication device including the antenna apparatus according to Embodiments 4 to 8 of the present invention.

[0095] like Fig. 9 As shown, the second antenna conductor 416 of the antenna device 410 of the wireless communication device 450 according to Embodiment 4 has a shape in which the length (dimension in the Y-axis direction) increases as it moves away from the second connecting portion 20 along the width direction (X-axis direction). In addition, the width (dimension in the X-axis direction) of the second antenna conductor 416 is the same as the length of the top edge 14a of the first antenna conductor 14.

[0096] In addition, if Fig.10As shown, the second antenna conductor 516 of the antenna device 510 of the wireless communication device 550 of the fifth embodiment has a shape in which the length (dimension in the Y-axis direction) of the second antenna conductor 516 is greater in the center in the width direction (X-axis direction) than in the ends. In addition, the rear end edge 516a of the second antenna conductor 516, which is opposite to the top end edge 14a of the first antenna conductor 14, is linear and parallel to the top end edge 14a. In addition, the width (dimension in the X-axis direction) of the second antenna conductor 516 is the same as the length of the top end edge 14a of the first antenna conductor 14.

[0097] Furthermore, if Fig.11 As shown, the second antenna conductor 616 of the antenna device 610 of the wireless communication device 650 of the sixth embodiment has a shape in which the length (dimension in the Y-axis direction) of the second antenna conductor 616 is smaller in the center in the width direction (X-axis direction) than in the ends. In addition, the top edge 616b of the second antenna conductor 616 on the side opposite to the rear end edge 616a opposite to the top edge 14a of the first antenna conductor 14 is linear and parallel to the top edge 14a of the first antenna conductor 14. In addition, the width (dimension in the X-axis direction) of the second antenna conductor 616 is the same as the length of the top edge 14a of the first antenna conductor 14.

[0098] Such Embodiments 4 to 6 can also enable an antenna device that communicates in a wide-band high frequency band to communicate in a low frequency band while suppressing an increase in size, similar to the above-mentioned Embodiment 1.

[0099] In addition, if Fig.12 As shown, the second antenna conductor 716 of the antenna device 710 of the wireless communication device 750 of Embodiment 7 has a trapezoidal shape in which the rear edge 716a and the top edge 716b are parallel to each other, and the length of the top edge 716b is greater than the length of the rear edge 716a. The length of the rear edge 716a is greater than the length of the top edge 14a of the first antenna conductor 14.

[0100] Such Embodiment 7 can also enable an antenna device that communicates in a wide-band higher frequency band to communicate in a lower frequency band while suppressing an increase in size, as in the above-mentioned Embodiment 1. Furthermore, the bandwidth of the higher frequency band can be expanded.

[0101] Unlike the antenna device 710 of Embodiment 7, Fig.13 As shown, the second antenna conductor 816 of the antenna device 810 of the wireless communication device 850 of Embodiment 8 is a rectangular shape in which the rear edge 816a and the top edge 816b are parallel to each other and have the same length. The lengths of the rear edge 816a and the top edge 816b are shorter than the length of the top edge 14a of the first antenna conductor 14.

[0102] Such an eighth embodiment, like the first embodiment described above, can enable an antenna device that communicates in a wide-band high frequency band to communicate in a low frequency band while suppressing an increase in size.

[0103] In addition, for example, in the case of the above-mentioned embodiment 1, if Figure 2 As shown in FIG. 1 , the first antenna conductor 14 is in a triangular shape with the top edge 14a as the base. However, the embodiment of the present invention is not limited to the shape of the first antenna conductor in a triangular shape.

[0104] Fig.14 and Fig.15 Each of them is a partially enlarged view of a wireless communication device including the antenna apparatus according to Embodiment 9 and Embodiment 10 of the present invention.

[0105] like Fig.14 As shown, the first antenna conductor 914 of the antenna device 910 of the wireless communication device 950 of embodiment 9 has a shape extending from the power supply point 22 in the direction away from the ground conductor 12 (Y-axis direction) and the width (dimension in the X-axis direction) widens as a quadratic function as it moves away from the power supply point 22, that is, a so-called bowl shape.

[0106] In addition, if Fig.15 As shown, the first antenna conductor 1014 of the antenna device 1010 of the wireless communication device 1050 of embodiment 10 has a shape extending from the power supply point 22 in the direction away from the ground conductor 12 (Y-axis direction) and the width (dimension in the X-axis direction) linearly widens as it moves away from the power supply point 22, that is, a so-called trapezoidal shape.

[0107] Similar to the above-mentioned Embodiment 1, the above-mentioned Embodiment 9 and Embodiment 10 can enable an antenna device that communicates in a wide-band high frequency band to communicate in a low frequency band while suppressing an increase in size.

[0108] Furthermore, in the case of the above-mentioned embodiment 1, if Figure 2 As shown, the first antenna conductor 14 extends from the power supply point 22 in a direction away from the ground conductor 12. However, the embodiments of the present invention are not limited to this. For example, like a self-complementary antenna such as a bow tie antenna, the first antenna conductor may extend from the power supply point, and another antenna conductor may extend from the power supply point in the opposite direction.

[0109] That is, the antenna device of the embodiment of the present invention is broadly an antenna device comprising: a power supply point; a first antenna conductor extending from the power supply point in a direction away from the ground conductor, and having a width that becomes wider as it moves away from the power supply point; a second antenna conductor that is spaced apart from the top edge of the first antenna conductor and is opposite to the top edge of the first antenna conductor; a first connecting portion that connects the top edge of the first antenna conductor and the second antenna conductor via a capacitor; and a second connecting portion that connects the top edge of the first antenna conductor and the second antenna conductor via an inductor or a zero-ohm resistor, a first connecting point where the first connecting portion is connected to the first antenna conductor is closer to the center of the top edge of the first antenna conductor than a second connecting point where the second connecting portion is connected to the first antenna conductor.

[0110] Although the present invention has been described above by listing a plurality of embodiments, it is obvious to those skilled in the art that a certain embodiment can be combined with the whole or part of at least one other embodiment to provide yet another embodiment of the present invention.

[0111] Industrial Applicability

[0112] The present invention can be applied to an antenna device for dual frequencies.

Claims

1. An antenna device, wherein: The antenna device has: Power supply point; a first antenna conductor extending from the feed point and having a width increasing as it moves away from the feed point; a second antenna conductor facing the top edge of the first antenna conductor with a gap therebetween; a first connecting portion connecting a top edge of the first antenna conductor and the second antenna conductor via a capacitor; as well as a second connection portion that connects the top edge of the first antenna conductor and the second antenna conductor via an inductor or a zero-ohm resistor, A first connection point where the first connection portion is connected to the first antenna conductor is closer to the center of the top edge of the first antenna conductor than a second connection point where the second connection portion is connected to the first antenna conductor. The first connection point is located at the center of the top edge of the first antenna conductor. The second connection point is located at one end of the distal edge of the first antenna conductor.

2. The antenna device according to claim 1, wherein: The antenna device also has a ground conductor connected to the power supply point. The first antenna conductor extends in a direction away from the ground conductor.

3. The antenna device according to claim 2, wherein: The antenna device further includes a short-circuit conductor, one end of which is connected to the first antenna conductor, and the other end of which is connected to the ground conductor. A third connection point where the short-circuit conductor is connected to the first antenna conductor is closer to the second connection point than the first connection point.

4. The antenna device according to claim 3, wherein: One end of the short-circuit conductor is connected to the first antenna conductor via an inductor. The other end of the short-circuit conductor is connected to the ground conductor via an inductor.

5. The antenna device according to any one of claims 1 to 4, wherein: The width of the second antenna conductor is equal to or greater than the length of the top edge.

6. The antenna device according to any one of claims 1 to 4, wherein: The first antenna conductor has a triangular shape with the top edge as a base, and the second antenna conductor has a rectangular shape.

7. The antenna device according to claim 5, wherein: The first antenna conductor has a triangular shape with the top edge as a base, and the second antenna conductor has a rectangular shape.

8. The antenna device according to claim 6, wherein: The first antenna conductor has a triangular shape in which two oblique sides have different lengths.

9. The antenna device according to claim 7, wherein: The first antenna conductor has a triangular shape in which two oblique sides have different lengths.

10. A wireless communication device, wherein: The wireless communication device comprises: The antenna device according to any one of claims 1 to 9; and A power supply circuit supplies power to a power supply point of the antenna device.

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