Antenna device and method for manufacturing the same

Abstract

Even when mounted on a dielectric panel, it reduces the non-uniformity of the radiation pattern compared to conventional methods. [Solution] The antenna device 1 comprises an antenna module 10 configured as a microstrip antenna including planar feeding elements 14, 16 and a ground conductor 12, and strip-shaped parasitic elements 22, 23. The parasitic elements 22, 23 have a length of 3 / 4 or more of the operating wavelength λ of the antenna device 1. At least a portion of the parasitic elements 22, 23 is at a distance of 1 / 4 to 3 / 4 of the operating wavelength λ of the antenna device 1 from the ground conductor 12.

Description

Technical Field

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[0001] The present disclosure relates to an antenna device and a method for manufacturing the same.

Background Art

[0002] As a small and easily manufacturable antenna device, a microstrip antenna or a patch antenna has been proposed.

[0003] For example, Patent Document 1 discloses an array antenna device in which a planar antenna such as a patch antenna is used as an element antenna and a plurality of these element antennas are arranged.

Prior Art Documents

Patent Documents

[0004] <​​​​​​​​​​​​​​​​​​​​​​ The antenna device relating to the first aspect of this disclosure is An antenna device that is mounted on a dielectric panel, The aforementioned antenna device is An antenna module configured as a microstrip antenna including at least one feed element and a ground conductor having a planar shape, It comprises at least one unpowered element having a strip shape, The at least one of the unpowered elements has a length of 3 / 4 or more of the operating wavelength of the antenna device. At least a portion of the at least one unpowered element is located at a distance of 1 / 4 to 3 / 4 of the operating wavelength of the antenna device from the ground conductor.

[0008] According to the antenna device of the second aspect of this disclosure, in the antenna device of the first aspect, The antenna module is mounted on the dielectric panel such that the surface of the power supply element is in contact with the dielectric panel.

[0009] According to the antenna device of the third aspect of this disclosure, in the antenna device of the first or second aspect, The feeding element and the grounding conductor have sizes and relative positions determined such that at least a portion of the at least one unpowered element is at a distance of 3 / 8 or more of the operating wavelength of the antenna device from the feeding element.

[0010] According to the antenna device of the fourth aspect of this disclosure, in the antenna device of one of the first to third aspects, The at least one passive element is mounted on the dielectric panel such that the longitudinal direction of the at least one passive element coincides with the direction in which current flows in the power supply element.

[0011] According to the antenna device of the fifth aspect of this disclosure, in the antenna device of one of the first to fourth aspects, The at least one passive element is bent or curved such that at least one of the two ends of the at least one passive element is closer to the power supply element than the central part of the at least one passive element.

[0012] According to the sixth aspect of this disclosure, in the antenna device according to one of the first to fifth aspects, The dielectric panel is further included.

[0013] A method for manufacturing an antenna device according to a seventh aspect of this disclosure is: An antenna module configured as a microstrip antenna including at least one feed element and a ground conductor having a planar shape is mounted on a dielectric panel, The invention includes mounting at least one parasitic element having a strip shape and a length of at least 3 / 4 of the operating wavelength of the antenna device to the dielectric panel such that at least a portion of the at least one parasitic element is at a distance of at least 1 / 4 to 3 / 4 of the operating wavelength of the antenna device from the ground conductor. [Effects of the Invention]

[0014] According to one aspect of the present disclosure, even when the antenna is mounted on a dielectric panel, the non-uniformity of the radiation pattern can be reduced compared to conventional antennas. [Brief explanation of the drawing]

[0015] [Figure 1] This is a perspective view showing the configuration of the antenna device 1 according to the first embodiment. [Figure 2] Figure 1 is a cross-sectional view showing the configuration of the antenna module 10. [Figure 3] Figure 1 is a plan view showing the configuration of the antenna device 1. [Figure 4] This figure shows the radiation pattern of the first feed element of the antenna device according to the first comparative example. [Figure 5]It is a diagram showing a radiation pattern related to the first power supply element of the antenna device according to the second comparative example. [Figure 6] It is a diagram showing a radiation pattern related to the second power supply element of the antenna device according to the second comparative example. [Figure 7] It is a diagram showing a radiation pattern related to the first power supply element 14 of the antenna device 1 in FIG. 1. [Figure 8] It is a diagram showing a radiation pattern related to the second power supply element 16 of the antenna device 1 in FIG. 1. [Figure 9] It is a plan view showing the configuration of the antenna device 1A according to the first modification of the first embodiment. [Figure 10] It is a diagram showing a radiation pattern related to the first power supply element 14 of the antenna device 1A in FIG. 9. [Figure 11] It is a plan view showing the configuration of the antenna device 1B according to the second modification of the first embodiment. [Figure 12] It is a diagram showing a radiation pattern related to the first power supply element 14 of the antenna device 1B in FIG. 11. [Figure 13] It is a plan view showing the configuration of the antenna device 1C according to the second embodiment. [Figure 14] It is a diagram showing a radiation pattern related to the first power supply element of the antenna device according to the third comparative example. [Figure 15] It is a diagram showing a radiation pattern related to the first power supply element 14 of the antenna device 1C in FIG. 13. [Figure 16] It is a plan view showing the configuration of the antenna device 1D according to the third embodiment. [Figure 17] It is a diagram showing a radiation pattern related to the power supply element of the antenna device according to the fourth comparative example. [Figure 18] It is a diagram showing a radiation pattern related to the power supply element 14 of the antenna device 1D in FIG. 16.

Embodiments for Carrying Out the Invention

[0016] Hereinafter, antenna devices according to each embodiment of the present invention will be described with reference to the drawings. Throughout the drawings, the same reference numerals indicate the same components.

[0017] [First Embodiment] [Configuration of the first embodiment] Figure 1 is a perspective view showing the configuration of an antenna device 1 according to a first embodiment. The antenna device 1 comprises an antenna module 10, a dielectric panel 21, and parasitic elements 22, 23.

[0018] Figure 2 is a cross-sectional view showing the configuration of the antenna module 10 in Figure 1. The antenna module 10 comprises a dielectric substrate 11, a ground conductor 12, a dielectric substrate 13, a feeding element 14, a dielectric substrate 15, a feeding element 16, and feeding lines 17 and 18.

[0019] The ground conductor 12 is a conductor pattern formed on at least one surface of a flat dielectric substrate 11. The ground conductor 12 has a planar shape. The dielectric substrate 11 and the ground conductor 12 may be configured as a multilayer substrate including a plurality of conductor layers connected to each other via via conductors.

[0020] The feeding element 14 is a conductor pattern formed on one side of a flat dielectric substrate 13. The feeding element 16 is a conductor pattern formed on one side of a flat dielectric substrate 15. The feeding elements 14 and 16 have a planar shape. The feeding elements 14 and 16 are placed on the ground conductor 12 via the dielectric substrates 13 and 15. The feeding elements 14 and 16 and the ground conductor 12 constitute a microstrip antenna.

[0021] The power supply line 17 comprises an internal conductor 17a connected to the power supply element 14 at the power supply point F1 and an external conductor 17b connected to the ground conductor 12. The power supply line 18 comprises an internal conductor 18a connected to the power supply element 16 at the power supply point F2 and an external conductor 18b connected to the ground conductor 12. The power supply lines 17 and 18 are connected to a wireless communication circuit (not shown) provided on the underside of the dielectric substrate 11 or at another location.

[0022] Referring again to Figure 1, the antenna module 10 and the parasitic elements 22, 23 are mounted on the dielectric panel 21, on its underside in the example shown in Figure 1. The dielectric panel 21 is, for example, the housing of the device, a windowpane, etc. The antenna module 10 is mounted on the dielectric panel 21 such that the surfaces of the feeding elements 14, 16 are in contact with the dielectric panel 21. More specifically, the antenna module 10 may be mounted on the dielectric panel 21 such that the surfaces of the feeding elements 14, 16 are in direct contact with the dielectric panel 21, in contact via an insulating coating or dielectric layer, or in contact via a thin layer of air. The parasitic elements 22, 23 are mounted on the dielectric panel 21 at a predetermined distance from the ground conductor 12. The parasitic elements 22, 23 have a strip shape, or a linear shape in the first embodiment.

[0023] The microstrip antennas, each containing a power supply element 14 and 16, have a main beam direction in the +Z direction in Figure 1 and transmit and receive radio waves via the dielectric panel 21.

[0024] Figure 3 is a plan view showing the configuration of the antenna device 1 in Figure 1. Figure 3 is a view of the antenna device 1 in Figure 1 from below. For explanatory purposes, dielectric substrates 11, 13, and 15 are omitted, and only the outline of the ground conductor 12 is shown.

[0025] The dielectric panel 21 has a rectangular shape with length d1 × d2. The ground conductor 12 has a rectangular shape with length d11 × d12. The feeding elements 14 and 16 each have a rectangular shape with length d13 × d14. The feeding elements 14 and 16 are arranged with a distance d15 between them that is less than half the free-space operating wavelength λ0 of the antenna module 10. The unpowered elements 22 and 23 each have a strip shape with length d16. The unpowered elements 22 and 23 are arranged with a distance d21 from the ground conductor 12 and a distance d22 from the feeding elements 14 and 16.

[0026] In the power supply elements 14 and 16, the power supply points F1 and F2 are located at the center in the Y direction and offset from the center in the X direction, respectively. By exciting the power supply elements 14 and 16 via the power supply points F1 and F2, current flows in the X direction in the power supply elements 14 and 16.

[0027] The passive elements 22 and 23 are mounted on the dielectric panel 21 such that their longitudinal directions coincide with the direction in which current flows in the power supply elements 14 and 16. In other words, if current flows in the X direction in the power supply elements 14 and 16, the passive elements 22 and 23 are mounted on the dielectric panel 21 such that current flows in the X direction on them.

[0028] As shown in Figure 1, when the antenna module 10 and the parasitic elements 22, 23 are mounted on the dielectric panel 21, the antenna device 1 has an operating wavelength λ that is shorter than the free-space operating wavelength λ0 of the antenna module 10 due to the influence of the dielectric panel 21. The length d16 of the parasitic elements 22, 23 is set to be 3 / 4 or more of the operating wavelength λ of the antenna device 1. The distance d21 from the ground conductor 12 to the parasitic elements 22, 23 is set to be between 1 / 4 and 3 / 4 of the operating wavelength λ of the antenna device 1. The distance d22 from the ground conductor 12 to the feed elements 14, 16 is set to be 3 / 8 or more of the operating wavelength λ of the antenna device 1. The feed elements 14, 16 and the ground conductor 12 have sizes and relative positions determined such that at least a portion of the parasitic elements 22, 23 is at a distance of 3 / 8 or more of the operating wavelength λ of the antenna device 1 from the feed elements 14, 16.

[0029] The antenna device 1 may be used, for example, to detect the angle of arrival (AoA) of radio waves based on the phase difference of arrival (PDoA) of the radio waves arriving at the feed elements 14 and 16.

[0030] [Operation of the first embodiment] Figure 4 shows the radiation pattern of the first feeding element of the antenna device according to the first comparative example. The antenna device according to the first comparative example has the dielectric panel 21 and the passive elements 22 and 23 removed from the antenna device 1 of Figure 1, i.e., it includes only the antenna module 10. Figure 4 shows the three-dimensional radiation pattern of the feeding element 14. When not affected by the dielectric panel 21, the antenna module 10 operates as shown in Figure 4.

[0031] Figure 5 shows the radiation pattern related to the first feeding element of the antenna device according to the second comparative example. Figure 6 shows the radiation pattern related to the second feeding element of the antenna device according to the second comparative example. The antenna device according to the second comparative example has a configuration in which the passive elements 22 and 23 are removed from the antenna device 1 of Figure 1. Figure 5 shows the three-dimensional radiation pattern related to the feeding element 14, and Figure 6 shows the three-dimensional radiation pattern related to the feeding element 16. The dielectric panel 21 has a rectangular shape with a length d1 × d2 = 100 × 140 mm, a thickness of 2 mm, and a relative permittivity of 5.7. When the antenna module 10 is attached to the dielectric panel 21, interference occurs due to radio waves propagating through the dielectric panel 21, causing the gain to increase or decrease depending on the azimuth angle and elevation angle, resulting in a non-uniform radiation pattern. In this case, for example, as shown in Figures 5 and 6, several nulls occur in the radiation pattern.

[0032] Figure 7 shows the radiation pattern related to the first feeding element 14 of the antenna device 1 in Figure 1. Figure 8 shows the radiation pattern related to the second feeding element 16 of the antenna device 1 in Figure 1. Figure 7 shows the three-dimensional radiation pattern related to the feeding element 14, and Figure 8 shows the three-dimensional radiation pattern related to the feeding element 16. Comparing Figure 5 and Figure 7, it can be seen that the non-uniformity of the radiation pattern is mitigated in Figure 7, for example, the amount of gain reduction at the null position in Figure 5 is smaller in Figure 7. Similarly, comparing Figure 6 and Figure 8, it can be seen that the non-uniformity of the radiation pattern is mitigated in Figure 8, for example, the amount of gain reduction at the null position in Figure 6 is smaller in Figure 8. Thus, it can be seen that the non-uniformity of the radiation pattern is reduced by attaching the unpowered elements 22 and 23 to the dielectric panel 21.

[0033] The inventors investigated the preferred ranges of lengths d16, d21, and d22 in Figure 3 through simulation. When the length d16 of the passive elements 22 and 23 was varied from λ / 2 to 3λ, the non-uniformity of the radiation pattern could be significantly reduced in the range d16≧3λ / 4. Furthermore, when the distance d21 from the ground conductor 12 to the passive elements 22 and 23 was varied from 0 to λ, the non-uniformity of the radiation pattern could be significantly reduced in the range λ / 4≦d21≦3λ / 4. In addition, when d21=λ / 4 and the distance d22 from the ground conductor 12 to the power supply elements 14 and 16 was varied from λ / 4 to 3λ / 2, in other words, when the dimension d12 of the ground conductor 12 was changed so that the distance d22 changed, the non-uniformity of the radiation pattern could be significantly reduced in the range d22≧3λ / 8.

[0034] As mentioned above, the antenna device 1 has an operating wavelength λ that is shorter than the free-space operating wavelength λ0 of the antenna module 10 due to the influence of the dielectric panel 21. For example, when the antenna device 1 operates at 8 GHz and the dielectric panel 21 has a relative permittivity of 7.2, the operating wavelength λ is 14 mm. In this case, for example, when d13=λ / 2=8 mm, d16=3λ / 4=10.5 mm, d21=λ / 4=3.5 mm, and d22=5.7 mm ≥ 3λ / 8=5.3 mm is set, the antenna device 1 was able to effectively reduce the non-uniformity of the radiation pattern.

[0035] [Effects of the first embodiment] According to the antenna device 1 of the first embodiment, even when the antenna module 10 is attached to the dielectric panel 21, the non-uniformity of the radiation pattern can be reduced compared to conventional methods by further attaching the parasitic elements 22 and 23 to the dielectric panel 21.

[0036] For example, when estimating the direction of arrival of radio waves, if the gain of the antenna device fluctuates according to the azimuth and elevation angles, the characteristics of the PDoA, which is electrical information for estimating the direction of arrival of radio waves based on nulls, deteriorate, making it difficult or impossible to accurately estimate the direction of arrival of radio waves. The antenna device 1 according to the first embodiment can also be used for estimating the direction of arrival of radio waves because it reduces the non-uniformity of the radiation pattern compared to conventional devices.

[0037] Patent Document 1 discloses an array antenna device equipped with a coupling line that connects adjacent patch antennas. This coupling line is provided to reduce mutual coupling between element antennas. On the other hand, according to the antenna device 1 of the first embodiment, the unfed elements 22 and 23 are provided not to control mutual coupling between the fed elements 14 and 16, but to reduce non-uniformity of the radiation pattern. Therefore, the antenna device 1 of this embodiment has novel effects that differ from those of the array antenna device of Patent Document 1. The operating principle of the antenna device 1 of this embodiment is also effective when the antenna device is equipped with a single fed element, as will be described later in the third embodiment.

[0038] [Modified version of the first embodiment] Figure 9 is a plan view showing the configuration of an antenna device 1A according to a first modification of the first embodiment. Antenna device 1A includes parasitic elements 22A and 23A that are bent at one point, instead of the linear parasitic elements 22 and 23 in Figure 3.

[0039] The passive elements 22A and 23A are mounted on the dielectric panel 21 such that at least a portion of each passive element 22A and 23A is at a distance d21 (λ / 4 ≤ d21 ≤ 3λ / 4) from the ground conductor 12. Furthermore, the passive elements 22A and 23A are bent so that two ends of each passive element 22A and 23A are closer to the feed elements 14 and 16 than the central portion of each passive element 22A and 23A. This further reduces the non-uniformity of the radiation pattern compared to the first embodiment.

[0040] Figure 10 shows the radiation pattern related to the first feeding element 14 of the antenna device 1A in Figure 9. Figure 10 shows the three-dimensional radiation pattern related to the feeding element 14. Comparing Figure 7 and Figure 10, it can be seen that the non-uniformity of the radiation pattern is further mitigated in the case of Figure 10. Thus, it can be seen that the non-uniformity of the radiation pattern is further reduced by bending the ends of the unpowered elements 22A and 23A toward the feeding elements 14 and 16.

[0041] Figure 11 is a plan view showing the configuration of an antenna device 1B according to a second modification of the first embodiment. Antenna device 1B includes parasitic elements 22B and 23B that are bent at two points, instead of the parasitic elements 22A and 23A that are bent at one point in Figure 9.

[0042] Figure 12 shows the radiation pattern related to the first feeding element 14 of the antenna device 1B in Figure 11. Figure 12 shows the three-dimensional radiation pattern related to the feeding element 14. Comparing Figure 7 and Figure 12, it can be seen that the non-uniformity of the radiation pattern is further mitigated in the case of Figure 12 as well. Thus, it can be seen that the non-uniformity of the radiation pattern is further reduced by bending the ends of the unpowered elements 22B and 23B toward the feeding elements 14 and 16.

[0043] Instead of bending as shown in Figures 10 and 12, the passive element may be curved such that its two ends are closer to the power supply elements 14 and 16 than to its central portion. In this case, the passive element may have, for example, a semicircular or U-shaped form.

[0044] [Second Embodiment] Figure 13 is a plan view showing the configuration of an antenna device 1C according to a second embodiment. When the antenna module 10 is mounted near the edge of the dielectric panel 21, the antenna device 1C may include one parasitic element 22.

[0045] Figure 14 shows the radiation pattern of the first feeding element of the antenna device according to the third comparative example. The antenna device according to the third comparative example has a configuration in which the parasitic element 22 is removed from the antenna device 1C of Figure 13. Figure 14 shows the three-dimensional radiation pattern of the feeding element 14. When the antenna module 10 is mounted off-center from the dielectric panel 21, the effect of interference is greater than when the antenna module 10 is mounted in the center of the dielectric panel 21. Comparing Figure 5 and Figure 14, it can be seen that the non-uniformity of the radiation pattern is greater in the case of Figure 14.

[0046] Figure 15 shows the radiation pattern related to the first feeding element 14 of the antenna device 1C in Figure 13. Figure 15 shows the three-dimensional radiation pattern related to the feeding element 14. Comparing Figure 14 and Figure 15, it can be seen that the non-uniformity of the radiation pattern is mitigated in the case of Figure 15. Thus, it can be seen that the non-uniformity of the radiation pattern is reduced by attaching one passive element 22 to the dielectric panel 21.

[0047] [Third Embodiment] Figure 16 is a plan view showing the configuration of an antenna device 1D according to a third embodiment. Antenna device 1A includes an antenna module 10D instead of the antenna module 10 shown in Figures 1 to 3. Antenna module 10D has a configuration in which the dielectric substrate 15 and the feeding element 16 are removed from the antenna module 10 shown in Figures 1 to 3.

[0048] Figure 17 shows the radiation pattern related to the feeding element of the antenna device according to the fourth comparative example. The antenna device according to the fourth comparative example has a configuration in which the passive elements 22 and 23 are removed from the antenna device 1D of Figure 16. Figure 17 shows the three-dimensional radiation pattern related to the feeding element 14. When the antenna module 10D is attached to the dielectric panel 21, interference occurs due to radio waves propagating through the dielectric panel 21, causing the gain to increase or decrease depending on the azimuth and elevation angles, resulting in a non-uniform radiation pattern.

[0049] Figure 18 shows the radiation pattern related to the feed element 14 of the antenna device 1D in Figure 16. Figure 18 shows the three-dimensional radiation pattern related to the feed element 14. Comparing Figure 17 and Figure 18, it can be seen that the non-uniformity of the radiation pattern is mitigated in the case of Figure 18. Thus, it can be seen that the non-uniformity of the radiation pattern is reduced by attaching the unpowered elements 22 and 23 to the dielectric panel 21.

[0050] [Other embodiments] The power supply element may have a shape other than a rectangle, for example, a circular shape.

[0051] If the antenna module has one feeding element, the unpowered element may be bent or curved such that only one of the two ends of the unpowered element is closer to the feeding element than the central part of the unpowered element.

[0052] The second and third embodiments may be combined, in which case the antenna device may include an antenna module with one feeding element and one unfed element. [Industrial applicability]

[0053] An antenna device according to one aspect of this disclosure can be applied, for example, to the estimation of the direction of arrival of radio waves. [Explanation of Symbols]

[0054] 1,1A~1D Antenna Equipment 10,10D Antenna Module 11 Dielectric substrate 12 Ground conductor 13 Dielectric substrate 14 Power supply element 15 Dielectric substrate 16 Power supply element 17,18 Power supply lines 21 Dielectric Panel 22, 23, 22A, 23A, 22B, 23B Unpowered element

Claims

1. An antenna device that is mounted on a dielectric panel, The aforementioned antenna device is An antenna module configured as a microstrip antenna including at least one feed element having a planar shape and a ground conductor, It comprises at least one unpowered element having a strip shape, The at least one of the unpowered elements has a length of 3 / 4 or more of the operating wavelength of the antenna device. At least a portion of the at least one passive element is located at a distance of 1 / 4 to 3 / 4 of the operating wavelength of the antenna device from the ground conductor. Antenna device.

2. The antenna module is mounted on the dielectric panel such that the surface of the power supply element is in contact with the dielectric panel. The antenna device according to claim 1.

3. The feeding element and the grounding conductor have a size and relative position determined such that at least a portion of the at least one unpowered element is at a distance of 3 / 8 or more of the operating wavelength of the antenna device from the feeding element. The antenna device according to claim 1 or 2.

4. The at least one passive element is mounted on the dielectric panel such that the longitudinal direction of the at least one passive element coincides with the direction in which current flows in the power supply element. The antenna device according to any one of claims 1 to 3.

5. The at least one passive element is bent or curved such that at least one of the two ends of the at least one passive element is closer to the power supply element than the central part of the at least one passive element. The antenna device according to one of claims 1 to 4.

6. The dielectric panel further comprises, The antenna device according to one of claims 1 to 5.

7. A method for manufacturing an antenna device, An antenna module configured as a microstrip antenna including at least one feed element and a ground conductor having a planar shape is mounted on a dielectric panel, This includes mounting at least one parasitic element having a strip shape and a length of 3 / 4 or more of the operating wavelength of the antenna device to the dielectric panel such that at least a portion of the at least one parasitic element is at a distance of 1 / 4 or more and 3 / 4 or less of the operating wavelength of the antenna device from the ground conductor. Manufacturing method.

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