Antenna device

Abstract

This antenna device comprises: an array antenna (1) that has element antennas (11) periodically arranged at element intervals (102a, 102b) along element array axes (101a, 101b); and a dielectric (21) that is disposed so as to face the array antenna (1) in a direction orthogonal to the element array axes (101a, 101b) and has holes (22) arranged at hole intervals (104a, 104b) that are 1 / n (n is an integer equal to or greater than 2) of the element intervals (102a, 102b) along hole array axes (103a, 103b) that are in the same direction as the element array axes (101a, 101b).

Description

Antenna device

[0001] The present disclosure relates to an antenna device including an array antenna.

[0002] 2. Description of the Related Art Conventionally, a tightly coupled dipole array antenna is known as an antenna device having a thin, wideband array antenna (see, for example, Patent Document 1).

[0003] The tightly coupled dipole array antenna described in Patent Document 1 is composed of a feed line, a balun, a dipole, and a matching layer. The balun is composed of an open stub and a short stub. In this tightly coupled dipole array antenna, a high frequency signal is fed by the feed line, and the dipole is differentially excited by the balun. In this tightly coupled dipole array antenna, a matching layer is provided above the dipole to enable the antenna to operate over a wide bandwidth. In this tightly coupled dipole array antenna, a dielectric with a low dielectric constant is generally used as the matching layer.

[0004] US Patent Application Publication No. 2014 / 0009356

[0005] As described above, matching layers used to broaden the bandwidth generally use dielectrics with low relative permittivity. However, dielectrics with low relative permittivity are expensive and difficult to obtain. Therefore, antenna devices equipped with matching layers using dielectrics with such low relative permittivity pose a problem of increased manufacturing costs. Furthermore, the relative permittivity of the matching layer required for a broad bandwidth varies depending on the configuration of the antenna device. Therefore, depending on the configuration of the antenna device, there may be cases where a dielectric with the desired relative permittivity is unavailable, making it difficult to narrow the operating frequency bandwidth.

[0006] The present disclosure has been made to solve the above-mentioned problems, and aims to provide an antenna device that is lower in cost and enables a wider bandwidth than conventional devices.

[0007] The antenna device according to the present disclosure is characterized by comprising an array antenna having element antennas arranged periodically at a first interval along a first array axis, and a dielectric having holes arranged at a second interval, which is 1 / n (n is an integer of 2 or greater) of the first interval, along a second array axis that is in the same direction as the first array axis, and arranged opposite the array antenna in a direction perpendicular to the first array axis.

[0008] According to the present disclosure, the above-described configuration makes it possible to achieve a wider bandwidth at lower cost than conventional techniques.

[0009] 1 is a perspective view showing an example of the configuration of an antenna device according to a first embodiment; FIG. 2 is a top view showing an example of the configuration of an array antenna according to the first embodiment; FIG. 3 is a top view showing an example of the configuration of a matching layer according to the first embodiment; FIG. 4 is a perspective view showing an example of the configuration of a unit cell in the antenna device according to the first embodiment; FIG. 5 is a top view showing another example of the configuration of the matching layer according to the first embodiment; FIG. 6 is a top view showing another example of the configuration of the matching layer according to the first embodiment; FIG. 7 is a perspective view showing an example of the configuration of a unit cell in an antenna device according to a second embodiment; FIG. 8 is an exploded perspective view showing an example of the configuration of a unit cell in an antenna device according to the second embodiment; FIG. 9 is a side view showing an example of the configuration of one layer of a dielectric substrate according to the second embodiment; FIG. 10 is a side view showing an example of the configuration of the other layer of a dielectric substrate according to the second embodiment; FIG. 11 is a diagram for explaining the effect of the antenna device according to the second embodiment, showing an example of current distribution on a dipole when a coupling conductor pattern is not provided on the dielectric substrate; FIG. 12 is a diagram for explaining the effect of the antenna device according to the second embodiment, showing an example of current distribution on a dipole when a coupling conductor pattern is provided on the dielectric substrate; FIG. 1 is an exploded perspective view showing an example of the configuration of a unit cell in an antenna device according to a third embodiment. FIG. 2 is a side view showing an example of the configuration of one layer of a dielectric substrate according to the third embodiment. FIG. 3 is a side view showing an example of the configuration of the other layer of a dielectric substrate according to the third embodiment. FIG. 4 is a diagram for explaining the effect of the antenna device according to the third embodiment, and is a side view showing an example of current distribution on a balun when a short-circuiting conductor pattern is not provided on the dielectric substrate. FIG. 5 is a diagram for explaining the effect of the antenna device according to the third embodiment, and is a diagram showing an example of current distribution on a balun when a short-circuiting conductor pattern is provided on the dielectric substrate. FIG. 6 is a perspective view showing an example of the configuration of a unit cell in an antenna device according to a fourth embodiment. FIG. 7 is an exploded perspective view showing an example of the configuration of a unit cell in an antenna device according to the fourth embodiment. FIG. 8 is a side view showing an example of the configuration of one layer of a dielectric substrate according to the fourth embodiment. FIG. 9 is a side view showing an example of the configuration of the other layer of a dielectric substrate according to the fourth embodiment.10 is a diagram for explaining the effect of the antenna device according to embodiment 4, showing a side view illustrating an example of current distribution when no resistor is provided on the dielectric substrate. FIG. 11 is a diagram for explaining the effect of the antenna device according to embodiment 4, showing a side view illustrating an example of current distribution when a resistor is provided on the dielectric substrate. FIG. 12 is a perspective view illustrating an example of a configuration of a unit cell in the antenna device according to embodiment 5. FIG. 13 is an exploded perspective view illustrating an example of a configuration of a unit cell in the antenna device according to embodiment 5. FIG. 14 is a side view illustrating an example of a configuration of one layer of the dielectric substrate according to embodiment 5. FIG. 15 is a side view illustrating an example of a configuration of the other layer of the dielectric substrate according to embodiment 5. FIG. 16 is a perspective view illustrating an example of a configuration of a unit cell in the antenna device according to embodiment 6. FIG. 17 is an exploded perspective view illustrating an example of a configuration of a unit cell in the antenna device according to embodiment 6. FIG. 18 is a diagram for explaining the effect of the antenna device according to embodiment 6, showing an example of an analytical value of the reflection coefficient for a horizontally polarized element. FIG. 19 is a diagram for explaining the effect of the antenna device according to embodiment 6, showing an example of an analytical value of the reflection coefficient for a vertically polarized element.

[0010] Hereinafter, embodiments will be described in detail with reference to the drawings. Embodiment 1. Fig. 1 is a perspective view showing an example of the configuration of an antenna device according to embodiment 1. Fig. 2 is a top view showing an example of the configuration of an array antenna 1 in embodiment 1. Fig. 3 is a top view showing an example of the configuration of a matching layer 2 in embodiment 1.

[0011] As shown in FIGS. 1 to 3, the antenna device includes an array antenna 1 and a matching layer 2.

[0012] As shown in FIGS. 1 and 2, the array antenna 1 has a plurality of element antennas 11.

[0013] The element antennas 11 are periodically arranged along element array axes (first array axes) 101a and 101b at predetermined element intervals (first intervals) 102a and 102b. Fig. 1 shows a case where the element antennas 11 are arranged in a square array. That is, in Fig. 1, the element array axes 101a and 101b are arranged so as to be orthogonal to each other.

[0014] The matching layer 2 is disposed opposite the array antenna 1 in a direction orthogonal (including the meaning of approximately orthogonal) to the element arrangement axes 101a and 101b. In Fig. 1, the matching layer 2 is disposed above the array antenna 1. As shown in Figs. 1 and 3, this matching layer 2 has a configuration in which a plurality of holes 22 are provided in a dielectric 21.

[0015] The holes 22 provided in this dielectric 21 are periodically arranged along hole arrangement axes (second arrangement axes) 103a and 103b at predetermined hole intervals (second intervals) 104a and 104b. The hole arrangement axes 103a and 103b are arrangement axes in the same direction (including substantially the same meaning) as the element arrangement axes 101a and 101b. The hole intervals 104a and 104b are 1 / n (n is an integer of 2 or greater) of the element intervals 102a and 102b. FIG. 1 shows a case where the holes 22 are arranged in a square array. That is, FIG. 1 shows the holes 22 arranged so that the hole arrangement axis 103a and the hole arrangement axis 103b are orthogonal to each other. FIG. 1 also shows a case where the shape of the holes 22 is circular. FIG. 1 also shows a case where the hole intervals 104a and 104b are 1 / 2 of the element intervals 102a and 102b.

[0016] Generally, an array antenna is configured by arranging a large number of unit cells, which are the smallest units. In the antenna device according to the first embodiment, the unit cells 10 are, for example, as shown in FIGS. 1 and 4.

[0017] Next, the effects of the antenna device according to the first embodiment will be described. When the characteristic impedance in free space is defined as η, the characteristic impedance of the matching layer is inversely proportional to √(εr). εr represents the relative dielectric constant of the matching layer. Therefore, by adjusting the relative dielectric constant or thickness of the matching layer 2, the input impedance looking into free space from the matching layer can be controlled. By adjusting this input impedance to a value suitable for widening the bandwidth of the array antenna, the bandwidth of the antenna device can be widened. Furthermore, even when controlling the phase of excitation of the element antennas and scanning the beam in a wide angle direction, matching design can be performed by adjusting the input impedance looking into free space from the matching layer, thereby expanding the coverage area of ​​the array antenna.

[0018] The input impedance can be adjusted by adjusting the dielectric constant and thickness of the matching layer. The dielectric constant and thickness of the matching layer required for broadband operation differ depending on the configuration of the antenna device, and a low dielectric constant is generally required.

[0019] Conventionally, a dielectric material with a low relative dielectric constant has been used as this matching layer, as described in Patent Document 1. Since such a dielectric material with a low relative dielectric constant is expensive and difficult to obtain, an increase in the manufacturing cost of the antenna device becomes an issue.

[0020] In contrast, in the antenna device according to the first embodiment, by using a dielectric 21 having a plurality of holes 22 as the matching layer 2, it is possible to lower the effective dielectric constant of the matching layer 2. By using such a dielectric 21 having holes 22, the antenna device according to the first embodiment can achieve a matching layer 2 with a low dielectric constant even if a dielectric having a relatively high dielectric constant that is generally used as the dielectric 21 is used. As a result, the antenna device according to the first embodiment can reduce manufacturing costs compared to conventional devices.

[0021] Furthermore, depending on the configuration of the antenna device, there may be a case where a dielectric having the desired relative dielectric constant required for broadening the bandwidth is not available, making it difficult to narrow the operating frequency band. In contrast, in the antenna device according to the first embodiment, it is possible to control the effective dielectric constant of the matching layer 2 by adjusting the shape of the hole 22 provided in the dielectric 21. This makes it possible to realize a matching layer 2 having an effective dielectric constant suitable for broadening the bandwidth. As a result, the antenna device according to the first embodiment can achieve a broader bandwidth than conventional devices.

[0022] Furthermore, if the hole spacings 104a and 104b are equal to the element spacings 102a and 102b, i.e., if n = 1, the dimensions of the holes 22 must be large to obtain a matching layer 2 with a low effective dielectric constant. In this case, the shape of the holes 22 may be approximately the wavelength. If the shape of the holes 22 is approximately the wavelength, the effective dielectric constant of the matching layer 2 may have frequency characteristics, resulting in a narrowband antenna device. Therefore, in the antenna device according to the first embodiment, the hole spacings 104a and 104b are set to 1 / n (where n is an integer greater than or equal to 2) of the element spacings 102a and 102b. As a result, in the antenna device according to the first embodiment, the shape of the holes 22 can be made equal to or smaller than the wavelength, thereby reducing the frequency characteristics of the effective dielectric constant of the matching layer 2.

[0023] Note that Figure 3 shows a case where the holes 22 provided in the matching layer 2 are circular and arranged in a square array. However, the shape and arrangement of the holes 22 are not limited to this. For example, Figure 5 shows a case where the holes 22 provided in the matching layer 2 are rectangular. Also, for example, Figure 6 shows a case where the holes 22 provided in the matching layer 2 are hexagonal. In this way, even when the holes 22 are not circular, the same effect as above can be obtained. Also, for example, Figure 7 shows a case where the holes 22 provided in the matching layer 2 are arranged in a triangular array. In this way, even when the holes 22 are not arranged in a square array, the same effect as above can be obtained.

[0024] As described above, according to the first embodiment, the antenna device includes an array antenna 1 having element antennas 11 periodically arranged at element spacings 102a and 102b along element array axes 101a and 101b, and a dielectric 21 having holes 22 arranged at hole spacings 104a and 104b that are 1 / n (n is an integer greater than or equal to 2) of the element spacings 102a and 102b along hole array axes 103a and 103b, which are in the same direction as the element array axes 101a and 101b, and disposed opposite the array antenna 1 in a direction perpendicular to the element array axes 101a and 101b. This allows the antenna device according to the first embodiment to achieve a broadband at lower cost than conventional devices. That is, the antenna device according to the first embodiment uses a dielectric 21 having a plurality of holes 22 formed therein as a matching layer 2. This allows the antenna device according to the first embodiment to reduce the effective dielectric constant of the matching layer 2. Therefore, in the antenna device according to the first embodiment, even if a dielectric having a relatively high dielectric constant is used as the dielectric 21, a matching layer 2 having a low dielectric constant can be realized, thereby reducing manufacturing costs compared to conventional devices. Furthermore, in the antenna device according to the first embodiment, the effective dielectric constant of the matching layer 2 can be controlled by adjusting the shape of the holes 22 formed in the dielectric 21. Therefore, in the antenna device according to the first embodiment, a matching layer 2 suitable for a broadband can be realized, thereby enabling a broader band than conventional devices. Furthermore, in the antenna device according to the first embodiment, the hole spacings 104a and 104b are set to 1 / n (n is an integer equal to or greater than 2) of the element spacings 102a and 102b. As a result, in the antenna device according to the first embodiment, the shape of the holes 22 can be made equal to or smaller than the wavelength, thereby reducing the frequency characteristics of the effective dielectric constant of the matching layer 2.

[0025] Second Embodiment Fig. 8 is a perspective view showing a configuration example of a unit cell 10 in an antenna device according to a second embodiment. Fig. 9 is an exploded perspective view showing a configuration example of a unit cell 10 in an antenna device according to the second embodiment. The antenna device according to the second embodiment shows a case in which a tightly coupled dipole is applied as the element antenna 11 to the antenna device according to the first embodiment. Other configuration examples of the antenna device according to the second embodiment are the same as the configuration example of the antenna device according to the first embodiment, and the same reference numerals are used and descriptions thereof will be omitted.

[0026] As shown in FIGS. 8 and 9, the element antenna 11 in the second embodiment has a metal plate 111 and a dielectric substrate 112.

[0027] The metal plate 111 is arranged along the element arrangement axes 101a and 101b. The metal plate 111 is formed with slots 113 into which the dielectric substrate 112 can be inserted. In Fig. 8, the slots 113 are formed along the element arrangement axis 101b.

[0028] The dielectric substrate 112 is inserted into the metal plate 111 through the slots 113 and is arranged in a direction perpendicular (including the meaning of approximately perpendicular) to the element arrangement axes 101a and 101b (metal plate 111). In Fig. 8, the dielectric substrate 112 is arranged along the element arrangement axis 101b.

[0029] Next, a description will be given of an example of the configuration of the dielectric substrate 112. Fig. 10 is a side view showing an example of the configuration of one layer of the dielectric substrate 112 according to the second embodiment, and Fig. 11 is a side view showing an example of the configuration of the other layer of the dielectric substrate 112 according to the second embodiment.

[0030] 9 to 11, a feed line 1121, a ground 1122, a balun 1123, a dipole 1124, and a coupling conductor pattern 1125 are formed on the dielectric substrate 112. In addition, in FIGS. 9 to 11, the balun 1123 is composed of an open stub 11231 and a short stub 11232.

[0031] The feed line 1121 is a metal conductor provided on one surface of the dielectric substrate 112. This feed line 1121 is a line for feeding a high-frequency signal. The ground 1122 is a metal conductor provided on one surface of the dielectric substrate 112. The open stub 11231 is a metal conductor provided on one surface of the dielectric substrate 112. One end of this open stub 11231 is connected to one end of the feed line 1121. The short stub 11232 is provided on the other surface of the dielectric substrate 112. The dipole 1124 is a metal conductor provided on the other surface of the dielectric substrate 112. The coupling conductor pattern 1125 is a conductor provided on one surface of the dielectric substrate 112 in a position overlapping two adjacent dipoles 1124 (see FIG. 13 ).

[0032] In this dielectric substrate 112, a high-frequency signal is fed by a feed line 1121, and dipoles 1124 are differentially excited by a balun 1123. In addition, in this dielectric substrate 112, in order to enhance coupling between adjacent dipoles 1124, coupling conductor patterns 1125 are formed so as to overlap with the dipoles 1124 via the dielectric substrate 112.

[0033] Next, the effects of the antenna device according to embodiment 2 will be described. Fig. 12 is a perspective view showing an example of the current distribution on the dipole 1124 when the coupling conductor pattern 1125 is not provided on the dielectric substrate 112. Fig. 13 is a perspective view showing an example of the current distribution on the dipole 1124 when the coupling conductor pattern 1125 is provided on the dielectric substrate 112. However, the matching layer 2 is not shown in Figs. 12 and 13.

[0034] 12, when the coupling conductor pattern 1125 is not provided on the dielectric substrate 112, the tip of the dipole 1124 is electrically open. Therefore, in this case, the current distribution 105 at the tip of the dipole 1124 becomes a low value, and the dipole resonates at a frequency where the dipole length is approximately half the wavelength. As a result, the antenna device has narrow-band electrical characteristics.

[0035] 13, when a coupling conductor pattern 1125 is provided on the dielectric substrate 112, adjacent dipoles 1124 are electromagnetically coupled by this coupling conductor pattern 1125, and the tips of the dipoles 1124 are not electrically open. Therefore, in this case, the antenna becomes a wideband antenna that operates over a wide band, not just at a frequency where the dipole length is approximately half the wavelength.

[0036] 9 shows a case where balun 1123 is composed of open stub 11231 and short stub 11232. However, the configuration of balun 1123 is not limited to this. For example, even if a tapered balun in which the shape of feed line 1121 is tapered is used as balun 1123, dipole 1124 can be excited differentially and the same effect as above can be obtained.

[0037] As described above, according to the second embodiment, the element antenna 11 includes the metal plate 111 arranged along the element array axes 101 a and 101 b, and the dielectric substrate 112 having the dipole 1124, which is a metal conductor, on one surface thereof, inserted into the metal plate 111 and arranged in a direction perpendicular to the element array axes 101 a and 101 b. The dielectric substrate 112 also has the coupling conductor pattern 1125, which is a metal conductor, on the other surface thereof at a position overlapping two adjacent dipoles 1124. As a result, the antenna device according to the second embodiment can achieve a wider bandwidth in addition to the effects of the first embodiment.

[0038] Third Embodiment Fig. 14 is a perspective view showing an example of the configuration of a unit cell 10 in an antenna device according to a third embodiment. Fig. 15 is an exploded perspective view showing an example of the configuration of a unit cell 10 in an antenna device according to the third embodiment. Fig. 16 is a side view showing an example of the configuration of one layer of a dielectric substrate 112 in the third embodiment, and Fig. 17 is a side view showing an example of the configuration of the other layer of a dielectric substrate 112 in the third embodiment. In the antenna device according to the third embodiment, a short-circuit conductor pattern 1126 is formed on the dielectric substrate 112, unlike the antenna device according to the second embodiment. The other example of the configuration of the antenna device according to the third embodiment is the same as the example of the configuration of the antenna device according to the second embodiment, and the same reference numerals are used, and description thereof will be omitted.

[0039] The short-circuiting conductor pattern 1126 is a metal conductor provided on one surface of the dielectric substrate 112. One end of the short-circuiting conductor pattern 1126 is connected to the coupling conductor pattern 1125, and the other end is connected to the ground 1122.

[0040] Next, the effects of the antenna device according to embodiment 3 will be described. Fig. 18 is a side view showing an example of current distribution on balun 1123 when dielectric substrate 112 does not have short-circuiting conductor pattern 1126. Fig. 19 is a side view showing an example of current distribution on balun 1123 when dielectric substrate 112 has short-circuiting conductor pattern 1126.

[0041] Balun 1123 is provided to differentially excite dipole 1124, but as shown in Fig. 18, not only differential mode current but also common mode current 106 is generated in balun 1123. This common mode current 106 resonates at a frequency where the spacing of balun 1123 is approximately half the wavelength, and this common mode resonance prevents dipole 1124 from being differentially excited. As a result, the electrical characteristics of the antenna device are significantly degraded.

[0042] It is known that connecting the dipole to ground with a short-circuiting conductor pattern is an effective method for reducing the effects of this common-mode resonance, but connecting a short-circuiting conductor pattern to the dipole changes the electrical characteristics of the dipole.

[0043] Therefore, in the antenna device according to the third embodiment, the coupling conductor pattern 1125 and the ground 1122 are connected using a short-circuiting conductor pattern 1126. As a result, a current flows through the short-circuiting conductor pattern 1126, as shown in FIG. 19 , for example. The current flowing through the short-circuiting conductor pattern 1126 cancels the common mode current 106, thereby reducing the effects of common mode resonance. As a result, the antenna device according to the third embodiment can suppress deterioration of electrical characteristics. Furthermore, the antenna device according to the third embodiment can also suppress fluctuations in the electrical characteristics of the dipole 1124.

[0044] As described above, according to the third embodiment, the dielectric substrate 112 has, on the other surface thereof, the short-circuiting conductor pattern 1126, which is a metal conductor having one end connected to the coupling conductor pattern 1125 and the other end connected to the ground 1122. As a result, the antenna device according to the third embodiment not only has the effect of the second embodiment, but also reduces the influence of common-mode resonance, enabling a wider bandwidth.

[0045] Fourth Embodiment Fig. 20 is a perspective view showing an example of the configuration of a unit cell 10 in an antenna device according to the fourth embodiment. Fig. 21 is an exploded perspective view showing an example of the configuration of a unit cell 10 in an antenna device according to the fourth embodiment. Fig. 22 is a side view showing an example of the configuration of one layer of a dielectric substrate 112 in the fourth embodiment, and Fig. 23 is a side view showing an example of the configuration of the other layer of a dielectric substrate 112 in the fourth embodiment. In the antenna device according to the fourth embodiment, a resistor 1127 is interposed in a short-circuit conductor pattern 1126, unlike the antenna device according to the third embodiment. The other example of the configuration of the antenna device according to the fourth embodiment is the same as the example of the configuration of the antenna device according to the third embodiment, and the same reference numerals are used, and description thereof will be omitted.

[0046] Resistor 1127 is provided on one surface of dielectric substrate 112. Resistor 1127 is interposed in short-circuiting conductor pattern 1126. In the antenna devices shown in Figures 20 to 23, resistor 1127 is provided at the other end of short-circuiting conductor pattern 1126. That is, in the antenna devices shown in Figures 20 to 23, one end of resistor 1127 is connected to the other end of short-circuiting conductor pattern 1126, and the other end of resistor 1127 is connected to ground 1122.

[0047] Next, the effects of the antenna device according to embodiment 4 will be described. Fig. 24 is a side view showing an example of current distribution when resistor 1127 is not provided on dielectric substrate 112. Fig. 24 is a side view showing an example of current distribution when resistor 1127 is provided on dielectric substrate 112.

[0048] 24 , when the coupling conductor pattern 1125 and the ground 1122 are connected by the short-circuiting conductor pattern 1126, a loop current 107a flowing through the balun 1123 and a loop current 107b flowing through the short-circuiting conductor pattern 1126 are formed. In this case, one loop current 107a excites the other loop current 107b, causing the loop current 107b to resonate. As a result, the antenna characteristics of the antenna device deteriorate.

[0049] Therefore, in the antenna device according to the fourth embodiment, a resistor 1127 is provided in the short-circuiting conductor pattern 1126. This suppresses the loop current 107b flowing through the short-circuiting conductor pattern 1126, as shown in Fig. 25 , for example, and makes it possible to reduce the influence of this loop resonance.

[0050] As described above, according to the fourth embodiment, the resistor 1127 is interposed in the short-circuiting conductor pattern 1126. As a result, the antenna device according to the fourth embodiment not only achieves the effects of the third embodiment, but also reduces the influence of loop resonance, enabling a wider bandwidth.

[0051] Fifth Embodiment Fig. 26 is a perspective view showing a configuration example of a unit cell 10 in an antenna device according to a fifth embodiment. Fig. 27 is an exploded perspective view showing a configuration example of a unit cell 10 in an antenna device according to the fifth embodiment. Fig. 28 is a side view showing a configuration example of one layer of a dielectric substrate 112 in the fifth embodiment, and Fig. 29 is a side view showing a configuration example of the other layer of a dielectric substrate 112 in the fifth embodiment. In the antenna device according to the fifth embodiment, a plurality of holes 1128 are provided in the ground of the feed line 1121, as compared to the antenna device according to the fourth embodiment. Other configuration examples of the antenna device according to the fifth embodiment are the same as those of the antenna device according to the fourth embodiment, and the same reference numerals are used, and description thereof will be omitted.

[0052] A plurality of holes 1128 are provided on the other surface of the dielectric substrate 112 in the ground of the feed line 1121 .

[0053] Next, the effects of the antenna device according to the fourth embodiment will be described. In unbalanced lines such as a microstrip line, a strip line, or a coplanar line, which are typical feed lines, the wider the gap between the signal line and the ground, the higher the characteristic impedance. Therefore, by providing a hole in the ground of the signal line, the gap between the signal line and the ground is widened, and the characteristic impedance of the feed line can be increased. Meanwhile, in this case, it is known that the input impedance of a tightly coupled dipole coupled to an adjacent dipole is approximately 200 Ω.

[0054] Therefore, the antenna apparatus according to the fifth embodiment uses a feed line 1121 having a plurality of holes 1128 formed in the ground. This makes it possible to excite the dipole 1124 with a feed line 1121 having a characteristic impedance close to the input impedance of the tightly coupled dipole, i.e., a feed line 1121 having a high characteristic impedance. As a result, the antenna apparatus according to the fifth embodiment makes it possible to configure an antenna with a wider bandwidth.

[0055] As described above, according to the fifth embodiment, dielectric substrate 112 has, on one surface thereof, feed line 1121 for feeding a high-frequency signal for exciting dipole 1124, and feed line 1121 has a plurality of holes 1128 formed in the ground. As a result, the antenna device according to the fifth embodiment can achieve a wider bandwidth in addition to the effects of the fourth embodiment.

[0056] Sixth embodiment Fig. 30 is a perspective view showing a configuration example of a unit cell 10 in an antenna device according to a sixth embodiment. Fig. 31 is an exploded perspective view showing a configuration example of a unit cell 10 in an antenna device according to a sixth embodiment. In the antenna device according to the sixth embodiment, a horizontally polarized element (first dielectric substrate) 112a and a vertically polarized element (second dielectric substrate) 112b are provided as the dielectric substrate 112, in contrast to the antenna device according to the fifth embodiment. The other configuration examples of the antenna device according to the sixth embodiment are the same as the configuration example of the antenna device according to the fifth embodiment, and the same reference numerals are used, and description thereof will be omitted.

[0057] Note that a slot 113 having two sides is formed in the metal plate 111 in the fifth embodiment. In Fig. 30, one side of the slot 113 is formed along the element arrangement axis 101a, and the other side is formed along the element arrangement axis 101b.

[0058] The horizontally polarized wave element 112a is a substrate for radiating radio waves in the horizontal direction. In Fig. 30, the horizontally polarized wave element 112a is arranged along the element array axis 101b.

[0059] The vertical polarization element 112b is arranged orthogonal (including the meaning of approximately orthogonal) to the horizontal polarization element 112a, and is a substrate for radiating radio waves in the vertical direction. In Fig. 30, the vertical polarization element 112b is arranged along the element array axis 101a.

[0060] The horizontally polarized wave element 112a and the vertically polarized wave element 112b are each configured in the same manner as the dielectric substrate 112 in the fifth embodiment.

[0061] With this configuration, the antenna device according to the sixth embodiment can emit orthogonal dual polarized radio waves in addition to the effects of the fifth embodiment.

[0062] Next, the effects of the antenna apparatus according to embodiment 6 will be described. Fig. 32 is a diagram showing an example of the analytical reflection coefficient value (electromagnetic field analysis result) for the horizontally polarized element 112a. Fig. 33 is a diagram showing an example of the analytical reflection coefficient value (electromagnetic field analysis result) for the vertically polarized element 112b. In Figs. 32 and 33, the horizontal axis and vertical axis respectively represent the frequency normalized by the low frequency f1 and the analytical reflection coefficient value.

[0063] As can be seen from Figures 32 and 33, the horizontal polarization element 112a and the vertical polarization element 112b have no unwanted resonance and provide reflection characteristics above the 6x band (reflection coefficient ≦−6 dB or less), confirming the effectiveness of embodiment 6.

[0064] In the above description, the antenna device according to embodiment 5 uses the horizontally polarized element 112a and the vertically polarized element 112b as the dielectric substrate 112. However, the present invention is not limited to this, and the antenna device according to embodiment 3 or embodiment 4 may use the horizontally polarized element 112a and the vertically polarized element 112b as the dielectric substrate 112, and the same effects as those described above can be obtained.

[0065] As described above, according to the sixth embodiment, dielectric substrate 112 has horizontally polarized element 112a and vertically polarized element 112b arranged orthogonal to each other. As a result, the antenna device according to the sixth embodiment can emit orthogonal dual polarized radio waves in addition to the effects of the third to fifth embodiments.

[0066] It should be noted that the embodiments may be freely combined, or any of the components in each embodiment may be modified, or any of the components in each embodiment may be omitted.

[0067] The antenna device according to the present disclosure is lower cost and allows for a wider bandwidth than conventional devices, and is suitable for use in antenna devices equipped with array antennas, etc.

[0068] 1 array antenna, 2 matching layer, 10 unit cell, 11 element antenna, 21 dielectric, 22 hole, 111 metal plate, 112 dielectric substrate, 112a horizontally polarized element (first dielectric substrate), 112b vertically polarized element (second dielectric substrate), 113 slot, 1121 feed line, 1122 ground, 1123 balun, 1124 dipole, 1125 coupling conductor pattern, 1126 short-circuit conductor pattern, 1127 resistor, 1128 hole, 11231 open stub, 11232 short stub.

Claims

1. An antenna device comprising: an array antenna having element antennas periodically arranged at a first interval along a first array axis; and a dielectric arranged with holes at a second interval which is 1 / n (n is an integer of 2 or more) of the first interval along a second array axis in the same direction as the first array axis, and arranged to face the array antenna in a direction orthogonal to the first array axis.

2. The antenna device according to claim 1, wherein the element antenna includes a metal plate arranged along the first array axis, and a dielectric substrate having a dipole which is a metal conductor on one surface thereof, and being inserted into the metal plate and arranged in a direction orthogonal to the first array axis.

3. The antenna device according to claim 2, wherein the dielectric substrate has a coupling conductor pattern which is a metal conductor on the other surface at a position overlapping two adjacent dipoles.

4. The antenna device according to claim 3, wherein the dielectric substrate has a short-circuit conductor pattern which is a metal conductor on the other surface, with one end connected to the coupling conductor pattern and the other end connected to ground.

5. The antenna device according to claim 4, wherein a resistor is interposed in the short-circuit conductor pattern.

6. The antenna device according to claim 5, wherein the dielectric substrate has a feeding line for feeding a high-frequency signal for exciting the dipole on one surface, and the feeding line is provided with a plurality of holes to ground.

7. The antenna device according to claim 4, wherein the dielectric substrate is a first dielectric substrate and a second dielectric substrate arranged to be orthogonal to each other.

8. The antenna device according to claim 5, wherein the dielectric substrate is a first dielectric substrate and a second dielectric substrate arranged to be orthogonal to each other.

9. The antenna device according to claim 6, wherein the dielectric substrate is a first dielectric substrate and a second dielectric substrate arranged to be orthogonal to each other.

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