Antenna element, array antenna, and wireless communication module

Abstract

An antenna element according to the present invention comprises: a substrate including a first ground conductor layer and a second ground conductor layer that face each other; a radiation conductor positioned on the opposite side of the second ground conductor layer from the first ground conductor layer; a power supply conductor positioned between the first ground conductor layer and the second ground conductor layer and extending along the first ground conductor layer; and a plurality of via conductors positioned from the first ground conductor layer to the second ground conductor layer. The plurality of via conductors are disposed on one side and the other side of the power supply conductor in the width direction orthogonal to the longitudinal direction of the power supply conductor, and the spacing of the plurality of via conductors in the width direction is 0.66λ to 1.43λ, where λ is the effective wavelength of a signal at the center frequency of the antenna band.

Description

Antenna element, array antenna, and wireless communication module

[0001] The present disclosure relates to an antenna element, an array antenna, and a wireless communication module.

[0002] WO 2018 / 212163 describes an antenna substrate having a radiation conductor that radiates electromagnetic waves and a feed conductor that supplies signal power to the radiation conductor.

[0003] The antenna element of the present disclosure comprises: a substrate having a first ground conductor layer and a second ground conductor layer facing each other; a radiation conductor located on the opposite side of the first ground conductor layer with the second ground conductor layer in between; a feed conductor located between the first and second ground conductor layers and extending along the first ground conductor layer; and a plurality of via conductors located from the first ground conductor layer to the second ground conductor layer, wherein the plurality of via conductors are arranged on either side of the feed conductor in a width direction perpendicular to the longitudinal direction of the feed conductor, and the spacing between the plurality of via conductors in the width direction is 0.66λ to 1.43λ, where λ is the effective wavelength of a signal at the center frequency of the antenna band.

[0004] The array antenna of the present disclosure comprises a plurality of the above antenna elements.

[0005] A wireless communication module according to the present disclosure includes the above array antenna and a signal processing circuit electrically connected to the array antenna.

[0006] 4A is a perspective perspective view showing an antenna element according to an embodiment of the present disclosure; FIG. 4B is a perspective plan view showing the antenna element of FIG. 1; FIG. 2A is a cross-sectional view taken along line B1-B1 of FIG. 2A; FIG. 2B is a cross-sectional view taken along line C1-C1 of FIG. 2A; FIG. 4C is a graph showing transmission characteristics of a transmission line along a feed conductor; FIG. 4D is a diagram explaining a resonance mode of a transmission line along a feed conductor; FIG. 4E is a diagram explaining a simulation model of a transmission line along a feed conductor; FIG. 4F is a graph showing transmission characteristics of a plurality of transmission lines with different spacings between via conductors; FIG. 4G is a graph enlarging the range of "-1 to 0 [dB]" of the graph of FIG. 4A; FIG. 4H is a graph enlarging the range of "-1 to 0 [dB]" of the graph of FIG. 4B; FIG. 4H is a graph showing the relationship between the spacing between via conductors and the worst value in a target frequency band; FIG. 4H is a plan view showing an array antenna and a wireless communication module according to an embodiment of the present disclosure; FIG. 7A is a cross-sectional view taken along line B2-B2 of FIG. 7A; FIG. 8A is a perspective perspective view showing an antenna element according to a second embodiment of the present disclosure; FIG. 8H is a cross-sectional view taken along line B3-B3 of FIG.

[0007] Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings. In this embodiment, the direction perpendicular to the surface of the first ground conductor layer 11, on which the radiation conductor 15 is located, will be described as "upward." The direction in the description may be different from the direction of the antenna element 1 when in use.

[0008] Fig. 1 is a perspective view showing an antenna element 1 according to an embodiment of the present disclosure. Fig. 2A is a perspective plan view showing the antenna element 1 of Fig. 1. Fig. 2B is a cross-sectional view taken along line B1-B1 in Fig. 2A. Fig. 2C is a cross-sectional view taken along line C1-C1 in Fig. 2A. The antenna element 1 of this embodiment includes a substrate 10, and a first ground conductor layer 11, a second ground conductor layer 12, a feed conductor 13, a plurality of via conductors 14a, 14b, 14c, and a radiation conductor 15, which are located on the substrate 10. The antenna element 1 may further include a slot 16.

[0009] The substrate 10 is a dielectric. The substrate 10 may be made of a ceramic material such as an aluminum oxide sintered body, a glass ceramic sintered body, a mullite sintered body, or an aluminum nitride sintered body. The layer occupying between the first ground conductor layer 11 and the second ground conductor layer 12 and the layer occupying above the second ground conductor layer 12 may have the same or different dielectric constants. The effective wavelength of the signal transmitted by the power supply conductor 13 corresponds to a wavelength based on the dielectric constant and frequency of the dielectric material occupying between the first ground conductor layer 11 and the second ground conductor layer 12.

[0010] The radiation conductor 15 is a conductor that emits or absorbs radio waves, and may be in the form of a film. The radiation conductor 15 may be rectangular in plan view, or may be square, polygonal, circular, or a combination of these shapes. The radiation conductor 15 may be located on the upper surface of the substrate 10, or may be located inside the substrate 10. Although FIG. 1 shows a configuration in which the antenna element 1 has one radiation conductor 15, the antenna element 1 may have multiple radiation conductors 15 located on multiple layers with a dielectric sandwiched between them. The multiple radiation conductors 15 may partially or completely overlap each other in planar perspective view.

[0011] The first ground conductor layer 11 and the second ground conductor layer 12 may be spaced apart and facing each other. The first ground conductor layer 11 and the second ground conductor layer 12 may be film-like conductors that extend in a plane, or their surfaces may be parallel to each other. The first ground conductor layer 11 and the second ground conductor layer 12 may be grounded conductors.

[0012] The power supply conductor 13 may be located between the first ground conductor layer 11 and the second ground conductor layer 12 and may extend along the first ground conductor layer 11. "Long along the first ground conductor layer 11" means that the power supply conductor 13 is approximately parallel to the first ground conductor layer 11 (i.e., within ±10° of strict parallelism) and does not intersect with the first ground conductor layer 11. The power supply conductor 13 may be located in the center between the first ground conductor layer 11 and the second ground conductor layer 12. The power supply conductor 13 may be located in the center of a region between the multiple via conductors 14a, 14b.

[0013] The feed conductor 13 may be configured to supply signal power to the radiation conductor 15 when the antenna element 1 transmits radio waves, and to receive signal power from the radiation conductor 15 when the antenna element 1 receives radio waves. The feed conductor 13 may be a long conductor along the signal path. The feed conductor 13 may be strip-shaped or rod-shaped. The feed conductor 13 may be linear, or may have a curved or bent portion that is bent in a two-dimensional direction along the first ground conductor layer 11.

[0014] One end or a portion of the feed conductor 13 may be connected to a signal processing circuit via a wiring conductor (not shown). The signal processing circuit is a circuit that processes signals to be transmitted or received. The other end or a portion of the feed conductor 13 may be configured to be electromagnetically coupled to the radiating conductor 15 via a dielectric, or may be configured to be electrically coupled via a feeding wiring conductor. Figure 1 shows the above-mentioned electromagnetic coupling configuration, in which the feed conductor 13 and the radiating conductor 15 are electromagnetically coupled via a slot 16 in the second ground conductor layer 12.

[0015] The via conductors 14a, 14b, and 14c may be columnar conductors extending from the first ground conductor layer 11 to the second ground conductor layer 12. The via conductors 14a, 14b, and 14c may sandwich the power supply conductor 13 and include via conductors 14a located on one side of the width direction of the power supply conductor 13 and via conductors 14b located on the other side of the power supply conductor 13 at a distance from the power supply conductor 13. Here, the width direction refers to a direction perpendicular to the longitudinal direction of the power supply conductor 13 in a planar perspective view, more specifically, a direction perpendicular to the longitudinal direction of the power supply conductor 13 and parallel to the first ground conductor layer 11. The via conductors 14a may be spaced apart in the longitudinal direction of the power supply conductor 13 to reduce leakage of high-frequency signals in the antenna frequency band. The multiple via conductors 14b may be positioned in the longitudinal direction of the power supply conductor 13 at intervals that reduce leakage of high-frequency signals in the antenna frequency band, more specifically, at intervals that are less than 1 / 4 or less than 1 / 8 of the effective wavelength of the high-frequency signals.

[0016] Hereinafter, the distance in the width direction between the plurality of via conductors 14a and the plurality of via conductors 14b will be referred to as "spacing L." More specifically, the spacing L is the distance in the width direction between the central axes of the plurality of via conductors 14a and the central axes of the plurality of via conductors 14b (see FIGS. 2A and 2B ). The spacing L corresponds to the spacing in the width direction between the imaginary wall connecting the plurality of via conductors 14a and the imaginary wall connecting the plurality of via conductors 14b. Therefore, even if one of the plurality of via conductors 14a is positioned relatively offset in the longitudinal direction of the power supply conductor 13 with respect to the other plurality of via conductors 14b, the spacing L does not change.

[0017] The via conductors 14c may be located in a region farther away from the power supply conductor 13 than the via conductors 14a and 14b. Some of the via conductors 14c may be located near the end of the power supply conductor 13 on the signal processing circuit side, and the via conductors 14c near the end may be located closer to the power supply conductor 13 than the via conductors 14a and 14b.

[0018] In Figure 2C, the area in which the power supply conductor 13 is surrounded by the first ground conductor layer 11, the second ground conductor layer 12, and the multiple via conductors 14a and 14b forms a transmission path (specifically, a stripline) through which signal power is transmitted.

[0019] The slot 16 corresponds to a portion of the second ground conductor layer 12 where the conductor is missing (i.e., where there is no conductor), and may be located between a part of the feed conductor 13 and the radiation conductor 15. The slot 16 may have a rectangular or dog-bone shape. In a planar perspective view, the longitudinal direction of the slot 16 may intersect with the longitudinal direction of the feed conductor 13.

[0020] With the above-described configuration, when transmitting radio waves, the antenna element 1 transmits signal power from the signal processing circuit via the feed conductor 13, and the signal power is sent to the radiation conductor 15 via the dielectric of the slot 16, and the radio waves are transmitted to the outside from the radiation conductor 15. When receiving radio waves, when the radiation conductor 15 receives radio waves from the outside, the signal power is sent from the radiation conductor 15 to the feed conductor 13 via the dielectric of the slot 16, and the signal power is transmitted to the signal processing circuit via the feed conductor 13. Since the feed conductor 13 is surrounded by the first ground conductor layer 11, the second ground conductor layer 12, and the via conductors 14a and 14b, high-frequency signal power can be transmitted with low loss.

[0021] <Transmission Characteristics of Transmission Line> Next, the transmission characteristics of the transmission line along the power supply conductor 13 will be described. This transmission line corresponds to the region in which the power supply conductor 13 is surrounded by the first ground conductor layer 11, the second ground conductor layer 12, and the multiple via conductors 14a and 14b, as shown in the cross-sectional view of FIG. 2C. FIG. 3A is a graph showing the transmission characteristics of the transmission line along the power supply conductor 13. FIG. 3B is a diagram explaining the resonance mode of the transmission line. FIG. 3C is a diagram explaining a model 20 for simulating the transmission line. In FIG. 3C, a plan view of the model 20 is shown on the left, and a side view of the model 20 is shown on the right.

[0022] The graph in Fig. 3A shows the results obtained by simulating the model 20 in Fig. 3C. The model 20 in Fig. 3C includes a dielectric substrate 22, planar, parallel first and second ground conductor layers 11 and 12 located on the dielectric substrate 22, and a linear, strip-shaped power supply conductor 13 located in the center layer between the first and second ground conductor layers 11 and 12. Signal power is transmitted from one end 13a to the other end 13b of the power supply conductor 13. The model 20 also includes a plurality of cylindrical via conductors 14a, 14b, and 14c located between the first and second ground conductor layers 11 and 12. The via conductors 14a and 14b are located at a certain distance apart, sandwiching the power supply conductor 13 in the width direction. The via conductors 14c are located in a region farther from the power supply conductor 13 than the via conductors 14a and 14b, and in a region surrounding the end of the power supply conductor 13 on the opposite side to the signal power transmission direction.

[0023] 3A, inverse peaks P11 and P12, where the transmission characteristic value drops significantly, appear at a first frequency ω1 and a second frequency ω2 on the transmission characteristic line of the transmission path. The first frequency ω1 and the second frequency ω2 are the frequencies of a low-order (e.g., first-order) resonance mode and a high-order (e.g., second-order) resonance mode, as described below. The resonance modes include higher-order (e.g., third-order, fourth-order, etc.) resonance modes, and although not shown, similar inverse peaks appear successively in even higher frequency bands.

[0024] Furthermore, a small inverse peak P13 where the transmission characteristic value becomes low appears on the transmission characteristic line of the transmission path at a third frequency ω3 between the first frequency ω1 and the second frequency ω2.

[0025] The transmission line surrounded by the first ground conductor layer 11, the second ground conductor layer 12, and the multiple via conductors 14a and 14b has a structure similar to that of a rectangular waveguide 31 as shown in Fig. 3B. Furthermore, simulations have shown that in frequency bands where the transmission characteristics are flat, the electric field distribution appearing in the transmission line contains many electric field components oriented from the feed conductor 13 toward the surrounding ground conductors. On the other hand, in frequency bands where an inverse peak appears in the transmission characteristic line, the electric field distribution appearing in the transmission line contains many electric field components oriented in the opposing direction between the first ground conductor layer 11 and the second ground conductor layer 12.

[0026] Based on these findings, it was considered that the inverse peaks P11 to P13 of the transmission characteristic curve occurring at the first frequency ω1, the second frequency ω2, and the third frequency ω3 are caused by a phenomenon similar to the resonance occurring in the rectangular waveguide 31. Specifically, it was considered that the inverse peaks occur when a propagation mode of the rectangular waveguide 31 occurs within the stripline formed by the feed conductor 13. That is, it was considered that the first frequency ω1 and the second frequency ω2 correspond to the lower and higher frequencies of a resonance mode in which the vertical electric field component E of the rectangular waveguide 31 has nodes at both ends in the width direction, as shown in FIG. 3B . Furthermore, it was considered that the third frequency ω3 corresponds to the frequency of the resonance mode of the electric field component in the propagation direction. The frequency of this resonance mode can be shifted higher by shortening the widthwise length L31 of the rectangular waveguide 31 (see FIG. 3B ).

[0027] <Spacing L in the width direction of the transmission path> If one or both of the first frequency ω1 and the second frequency ω2, at which the inverse peaks P11 and P12 of the transmission characteristic line appear, are included in the antenna frequency band, the characteristics of the antenna element 1 will be degraded. On the other hand, as can be inferred from the above considerations, the positions of the first frequency ω1 and the second frequency ω2, which degrade the transmission characteristics, change depending on the selection of the spacing L in the width direction of the transmission path (see Figures 2A and 2B). As a result, it is possible to exclude the first frequency ω1 and the second frequency ω2 from the antenna frequency band.

[0028] Here, if a general high frequency technology method is applied, the interval L is selected to be short so that the low order resonant frequencies are higher than the antenna frequency band, and by this selection, all resonant frequencies from low order to high order can be excluded from the antenna frequency band.

[0029] On the other hand, in this embodiment, the above-mentioned general method is not adopted, and the widthwise spacing L of the transmission line is selected using the following method. That is, in this embodiment, the widthwise spacing L of the transmission line, in other words, the spacing L between the multiple via conductors 14a, 14b in the widthwise direction, may be a value that satisfies the following formula (1): 0.66λ ≦ spacing L ≦ 1.43λ (1) where λ is the effective wavelength of the center frequency of the antenna frequency band. When the antenna frequency band is set to 57 GHz to 71 GHz and the relative dielectric constant εr of the substrate 10 is set to 5.7, the spacing L corresponds to 1.3 mm to 2.8 mm.

[0030] The above formula (1) corresponds to the condition for positioning the frequency of the lower inverse peak P11 appearing on the transmission characteristic line lower than the antenna frequency band, and for positioning the frequency of the higher inverse peak P12 higher than the antenna frequency band.

[0031] 4A and 4B are two graphs showing the transmission characteristics of eight transmission paths with different via conductor spacings L. The graphs were obtained by simulation using model 20 in FIG. 3C. The antenna frequency band B is assumed to be 57 GHz to 71 GHz.

[0032] As shown in the graph, when the distance L is 1 mm and 1.2 mm, the low-order frequency at which an inverse peak appears in the transmission characteristic line overlaps with the antenna frequency band B. When the distance L is 1.3 mm, the low-order frequency ω31 at which an inverse peak P21 appears in the transmission characteristic line is located near the antenna frequency band B but is shifted to the lower side. When the distance L is 2.8 mm, the high-order frequency ω82 at which an inverse peak P22 appears in the transmission characteristic line is located near the antenna frequency band B but is shifted to the higher side. When converted using the effective wavelength λ of the center frequency, 1.3 mm and 2.8 mm become 0.66λ and 1.43λ.

[0033] Therefore, due to the distance L in the above formula (1), the frequency at which a large inverse peak occurs in the transmission characteristic line is positioned outside the antenna frequency band B, and good transmission characteristics are obtained in the antenna frequency band B. This reduces loss in the signal power transmission path and improves the gain of the antenna element 1.

[0034] Furthermore, when antenna frequency band B is set to around 60 GHz, radio waves in this frequency band are significantly attenuated in the atmosphere, and improving the gain of antenna element 1 significantly affects the increase in the communication distance. Therefore, when this frequency band overlaps with antenna frequency band B, the antenna element 1 of this embodiment is particularly effective in increasing the communication distance. The increased communication distance allows the antenna element 1 to be applied to systems that require a long communication distance, thereby expanding the range of application.

[0035] Furthermore, with the spacing L determined as described above, a larger spacing L can be adopted compared to the spacing selected using the above-described general high-frequency technology. If a small spacing L is selected using the above-described general high-frequency technology, the spacing between the via conductors 14a and 14b will be narrow, resulting in stricter design rules (i.e., design regulations) for each part of the antenna element 1. Furthermore, if the spacing L is small, the spacing between the via conductors 14a and 14b will be narrower, increasing the total number of via conductors 14a, 14b, and 14c, including the multiple via conductors 14c located in other areas. On the other hand, by adopting a large spacing L as in this embodiment, the above-described stricter design rules can be alleviated, and the total number of multiple via conductors 14a, 14b, and 14c can be reduced. Furthermore, by increasing the spacing L between the via conductors 14a and 14b, the possibility of cracks occurring between the via conductors during the manufacturing process can be reduced. Furthermore, when a configuration is adopted in which the radiation conductor 15 and the feed conductor 13 are electromagnetically coupled via the slot 16, the distance L between the via conductors 14 a and 14 b can be increased, which reduces interference between the slot 16 and the via conductors 14 a and 14 b. This provides the advantage of increasing the degree of freedom in the layout of the slot 16 and the via conductors 14 a and 14 b.

[0036] Second Embodiment An antenna element 1 of a second embodiment is similar to that of the first embodiment except that the spacing L between the via conductors 14a and 14b in the width direction is different.

[0037] In the second embodiment, the distance L may be a value that satisfies the following formula (2): 0.66λ ≦ distance L ≦ 1.02λ (2), where λ is the effective wavelength of the center frequency of the antenna frequency band. When the antenna frequency band is set to 57 GHz to 71 GHz and the relative dielectric constant εr of the substrate 10 is set to 5.7, the distance L corresponds to 1.3 mm to 2.0 mm.

[0038] The above formula (2) corresponds to the condition of the first embodiment as well as the condition of positioning the frequency of a small inverse peak appearing in the transmission characteristic line (see inverse peak P13 of the third frequency ω3 in FIG. 3A ) outside the antenna frequency band B.

[0039] 5A and 5B are two graphs that respectively enlarge the range of "-1 to 0 [dB]" of the graphs of Figures 4A and 4B, and show the transmission characteristics of eight transmission paths with different via conductor spacing L. Antenna frequency band B is assumed to be 57 GHz to 71 GHz.

[0040] As shown in the graph, of the small reverse peaks p31 to p35 of the transmission characteristic line, the small reverse peaks p31 and p32 with spacing L of 2.4 mm and 2.2 mm overlap with the antenna frequency band B. Furthermore, the small reverse peaks p33 to p35 with spacing L of 1.2 mm, 2.0 mm, and 2.8 mm deviate from the antenna frequency band B. Between spacing L of 2.0 mm and 2.2 mm, there is a boundary as to whether the small reverse peaks overlap with or deviate from the antenna frequency band B. 2.0 mm is converted to 1.02λ using the effective wavelength λ of the center frequency.

[0041] Therefore, due to the interval L in the above formula (2), the frequency at which a large inverse peak occurs in the transmission characteristic line and the frequency at which a small inverse peak occurs are located outside the antenna frequency band B. Therefore, in addition to the effect of the first embodiment, better transmission characteristics are obtained in the antenna frequency band B. Therefore, loss in the transmission path of signal power is further reduced, and the gain of the antenna element 1 can be further improved.

[0042] Third Embodiment The antenna element 1 of a third embodiment is similar to that of the first embodiment except that the distance L between the via conductors 14a and 14b in the width direction is different.

[0043] In the third embodiment, the distance L may be a value that satisfies the following formula (3): 0.71λ ≦ distance L ≦ 1.33λ (3), where λ is the effective wavelength of the center frequency of the antenna frequency band. When the antenna frequency band is set to 57 GHz to 71 GHz and the relative dielectric constant εr of the substrate 10 is set to 5.7, the distance L corresponds to 1.4 mm to 2.6 mm.

[0044] The above formula (3) corresponds to the condition that the worst value of the transmission characteristic in antenna frequency band B is equal to or greater than a reference value (e.g., −0.4 dB) in addition to the condition in embodiment 1. The condition of being equal to or greater than the reference value corresponds to realizing transmission of 90% or more.

[0045] 6 is a graph showing the relationship between the worst value of the transmission characteristics and the distance L between the via conductors 14a and 14b in the antenna frequency band B. This graph is derived from the results of simulations performed for configurations with distance L = 1.4 mm and 1.8 mm, in addition to the simulation results of FIGS. 4A and 4B. The antenna frequency band B is assumed to be 57 GHz to 71 GHz.

[0046] As shown in the graph, the minimum value of the transmission characteristics in antenna frequency band B is significantly high when the spacing L is 1.4 mm to 2.6 mm. When 1.4 mm and 2.6 mm are converted using the effective wavelength λ of the center frequency, they become 0.71 λ and 1.33 λ.

[0047] Therefore, the spacing L in the above formula (3) makes the worst value of the transmission characteristics in the antenna frequency band B equal to or greater than the reference value. Therefore, in addition to the effects of the first embodiment, better transmission characteristics can be obtained in the antenna frequency band B. Therefore, the loss in the transmission path of the signal power can be further reduced, and the gain of the antenna element 1 can be further improved.

[0048] Fourth Embodiment The antenna element 1 of a fourth embodiment is similar to that of the first embodiment except that the distance L between the via conductors 14a and 14b in the width direction is different.

[0049] In the fourth embodiment, the distance L may be a value that satisfies the following formula (4): 0.71λ ≦ distance L ≦ 1.02λ (4), where λ is the effective wavelength of the center frequency of the antenna frequency band. When the antenna frequency band is set to 57 GHz to 71 GHz and the relative dielectric constant εr of the substrate 10 is set to 5.7, the distance L corresponds to 1.4 mm to 2.0 mm.

[0050] The above formula (4) corresponds to the condition that all of the conditions of embodiments 1 to 3 are satisfied. The interval L in formula (4) provides all of the advantages of embodiments 1 to 3, further reduces the loss of the signal power transmission path, and further improves the gain of the antenna element 1.

[0051] (Array Antenna and Wireless Communication Module) FIG. 7A is a perspective plan view showing an array antenna and a wireless communication module according to an embodiment of the present disclosure. FIG. 7B is a cross-sectional view taken along line B2-B2 in FIG. 7A . The array antenna 100 according to this embodiment includes a plurality of antenna elements 1 shown in embodiment 1, 2, 3, or 4. A wireless communication module 200 according to an embodiment of the present disclosure includes the array antenna 100 and an integrated circuit 210. The plurality of antenna elements 1 may be arranged vertically or horizontally, such as in a matrix, on a large array substrate 110, or may be arranged in any other manner. The array substrate 110 is a dielectric substrate. The feed conductor 13 of each antenna element 1 is electrically connected to an electrode 130 via a wiring conductor 111 on the side farther from the radiation conductor 15. An integrated circuit 210 incorporating a signal processing circuit is connected to the electrode 130.

[0052] The multiple antenna elements 1 of the array antenna 100 are integrated by sharing the substrate 10 (see FIG. 1 ) of the multiple antenna elements 1 on a single array substrate 110. Note that the configuration is not limited to this, and the array antenna 100 may be integrated by mounting multiple antenna elements 1 on a single array substrate. Furthermore, multiple array antennas 100 may be mounted on a single array substrate, thereby integrating more antenna elements 1.

[0053] According to the array antenna 100 and the wireless communication module 200 of this embodiment, the overall gain can be improved by reducing the loss of the signal power transmission path in the feed conductor 13 of each antenna element 1.

[0054] The above describes the embodiments of the present disclosure. However, the present invention is not limited to the above embodiments. For example, in the above embodiments, the coupling between the feed conductor 13 and the radiating conductor 15 is achieved by electromagnetic coupling via the slot 16. However, as shown in FIGS. 8A and 8B , a configuration in which the coupling between the feed conductor 13 and the radiating conductor 15 is achieved by electrical coupling via the wiring conductor 18 may be employed. FIG. 8A is a perspective view of an antenna element 1A according to a fifth embodiment of the present disclosure. FIG. 8B is a cross-sectional view taken along line B3-B3 in FIG. 8A . The wiring conductor 18 extends to the radiating conductor 15 through a through hole 17 in the second ground conductor layer 12. In the antenna element 1A of the fifth embodiment, a stacked patch having two patch conductors 15A and 15B is employed as the radiating conductor 15. The radiating conductor is not limited to the configuration shown in FIGS. 1 and 8A , and various other configurations may be employed. The antenna element 1A of the fifth embodiment or the antenna element of the above-described modification may be applied to the array antenna 100 and the wireless communication module 200 described above.

[0055] Furthermore, the via conductors 14a, 14b are not limited to the configuration shown in the drawings, and may have various shapes, such as a columnar configuration with a rectangular cross section, or a wall-like configuration extending along the power supply conductor. The antenna element of this modified example may be applied to the array antenna 100 and wireless communication module 200 described above. Other details shown in the embodiments may be modified as appropriate without departing from the spirit of the invention.

[0056] An embodiment of the present disclosure is described below. In one embodiment, (1) an antenna element comprises: a substrate having a first ground conductor layer and a second ground conductor layer facing each other, a radiation conductor located on the opposite side of the first ground conductor layer with the second ground conductor layer sandwiched therebetween, a feed conductor located between the first and second ground conductor layers and extending along the first ground conductor layer, and a plurality of via conductors located from the first ground conductor layer to the second ground conductor layer, wherein the plurality of via conductors are arranged on either side of the feed conductor in a width direction perpendicular to the longitudinal direction of the feed conductor, and the spacing between the plurality of via conductors in the width direction is 0.66λ to 1.43λ, where λ is the effective wavelength of a signal at the center frequency of the antenna band.

[0057] (2) In the antenna element of (1) above, the spacing between the plurality of via conductors in the width direction is 0.66λ to 1.02λ.

[0058] (3) In the antenna element of (1) above, the spacing between the plurality of via conductors in the width direction is 0.71λ to 1.33λ.

[0059] (4) The array antenna comprises a plurality of antenna elements (1) to (3) above.

[0060] (5) A wireless communication module includes the array antenna of (4) above, and a signal processing circuit electrically connected to the array antenna.

[0061] The present disclosure can be used for antenna elements, array antennas, and wireless communication modules.

[0062] REFERENCE SIGNS LIST 1 Antenna element 10 Substrate 11 First ground conductor layer 12 Second ground conductor layer 13 Power supply conductor 14a, 14b, 14c Via conductor 15 Radiation conductor 16 Slot L Spacing B Antenna frequency band 100 Array antenna 110 Array substrate 111 Wiring conductor 130 Electrode 200 Wireless communication module 210 Integrated circuit

Claims

1. An antenna element comprising: a substrate having a first ground conductor layer and a second ground conductor layer facing each other; a radiation conductor located on the opposite side of the first ground conductor layer with the second ground conductor layer in between; a feed conductor located between the first and second ground conductor layers and extending along the first ground conductor layer; and a plurality of via conductors located from the first ground conductor layer to the second ground conductor layer, wherein the plurality of via conductors are arranged on either side of the feed conductor in a width direction perpendicular to the longitudinal direction of the feed conductor, and the spacing between the plurality of via conductors in the width direction is 0.66λ to 1.43λ, where λ is the effective wavelength of a signal at the center frequency of the antenna band.

2. The antenna element according to claim 1, wherein the spacing between the plurality of via conductors in the width direction is 0.66λ to 1.02λ.

3. The antenna element according to claim 1, wherein the spacing between the plurality of via conductors in the width direction is 0.71λ to 1.33λ.

4. An array antenna comprising a plurality of antenna elements according to any one of claims 1 to 3.

5. A wireless communication module comprising the array antenna according to claim 4 and a signal processing circuit electrically connected to said array antenna.

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