JPWO2019198714A1 - Slot array antenna - Google Patents

Abstract

A dielectric layer, a feeding portion, a first coplanar line formed on a conductor layer provided on one surface of the dielectric layer, and a second coplanar line formed on the conductor layer are provided. The first coplanar line and the second coplanar line each have a first end connected to or close to the power feed portion and at least one slot formed in the conductor layer. A slot array antenna having at least one second end to be connected.

Description

The present invention relates to a slot array antenna.

In recent years, there has been a movement to expand services using high-speed, large-capacity wireless communication systems that use microwave and millimeter-wave frequency bands, such as the shift from 4G LTE to 5G (sub6). As an antenna used in such a frequency band, a slot array antenna that feeds a plurality of slots using a coplanar line is known (see, for example, Non-Patent Document 1).

J.McKnight et al., A Series-Fed Coplanar Waveguide Slot Antenna Array, 2010 IEEE 11th Annual Wireless and Microwave Technology Conference

However, in a slot array antenna as in Non-Patent Document 1, since power is supplied to a plurality of slots arranged in one direction by a common coplanar line, the direction of directivity is limited to the arrangement direction.

Therefore, the present disclosure provides a slot array antenna with improved design freedom in the direction of directivity.

This disclosure is
A dielectric layer, a feeding portion, a first coplanar line formed on a conductor layer provided on one surface of the dielectric layer, and a second coplanar line formed on the conductor layer are provided.
The first coplanar line and the second coplanar line are each a first end connected to or close to the power feeding portion and at least one slot formed in the conductor layer. Provides a slot array antenna having at least one second end to which the is connected.

According to the present disclosure, the degree of freedom in designing the direction of directivity is improved.

It is a top view which illustrates the slot array antenna of 1st Embodiment. It is a side view which illustrates the slot array antenna of 1st Embodiment. It is a side view which illustrates other configuration example of the slot array antenna of 1st Embodiment. It is a figure which illustrates the directivity of the slot array antenna of 1st Embodiment. It is a top view which illustrates the slot array antenna of 2nd Embodiment. It is a figure which illustrates the directivity of the slot array antenna of the 2nd Embodiment. It is a top view which illustrates the slot array antenna of 3rd Embodiment. It is a side view which illustrates the slot array antenna of 3rd Embodiment. It is a top view which illustrates the slot array antenna which includes the LC filter. It is an enlarged view of FIG. It is a figure which illustrates the filter characteristic of an LC filter. It is a top view which illustrates the slot array antenna of 4th Embodiment. It is a figure which illustrates the directivity of the slot array antenna of 4th Embodiment. It is a top view which illustrates the slot array antenna of 5th Embodiment. It is a top view which illustrates the slot array antenna of 6th Embodiment. It is a top view which illustrates the MIMO (Multiple-Input and Multiple-Output) antenna which includes a plurality of slot array antennas. It is a top view which illustrates the slot array antenna of 7th Embodiment. It is a figure which illustrates the directivity of the slot array antenna of the 1st Embodiment in the case of D1, D2 = λ / 4. It is a figure which illustrates the directivity of the slot array antenna of the 1st Embodiment in the case of D1, D2 = 2λ / 4. It is a figure which illustrates the directivity of the slot array antenna of the 1st Embodiment in the case of D1, D2 = 3λ / 4. It is a figure which illustrates the directivity of the slot array antenna of the 1st Embodiment in the case of D1, D2 = 4λ / 4.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings. In each form, deviations to the extent that the effects of the present invention are not impaired are allowed in the directions of parallel, right angle, orthogonal, horizontal, vertical, up / down, left / right, and the like. Further, the X-axis direction, the Y-axis direction, and the Z-axis direction represent a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. The XY plane, YZ plane, and ZX plane are a virtual plane parallel to the X-axis direction and the Y-axis direction, a virtual plane parallel to the Y-axis direction and the Z-axis direction, and a virtual plane parallel to the Z-axis direction and the X-axis direction, respectively. Represents.

The slot array antenna of the embodiment according to the present disclosure is a coplanar-fed flat array antenna that feeds a plurality of slots using a plurality of coplanar lines, and is a high-frequency band such as a microwave or a millimeter wave (for example). , 0.3 GHz to 300 GHz) is suitable for transmitting and receiving radio waves. The slot array antenna of the embodiment according to the present disclosure can be applied to, for example, a fifth generation mobile communication system (so-called 5G), an in-vehicle radar system, and the like, but the applicable system is not limited thereto.

FIG. 1 is a plan view illustrating the slot array antenna of the first embodiment according to the present disclosure. FIG. 2 is a side view illustrating the slot array antenna of the first embodiment. The slot array antenna 101 shown in FIGS. 1 and 2 is formed into a plurality of slot-shaped antenna elements via a coplanar line formed so as to branch to a conductor layer 43 provided on one side of the dielectric layer 40 at at least one position. It is an array antenna that feeds by coupling. By using a coplanar line in which the central conductor layer and the ground conductor layer are provided on the same plane as a feeding path to a plurality of slot-shaped antenna elements, an array antenna can be configured on one plane. Since the array antenna can be configured on one plane, the configuration is simple and high productivity can be realized as compared with, for example, a microstrip array antenna that uses both sides of the dielectric layer.

The slot array antenna 101 shown in FIGS. 1 and 2 includes a dielectric layer 40, a plurality of coplanar lines 10, 20, and 30, and a plurality of slots 51 to 54.

The dielectric layer 40 is a plate-shaped or sheet-shaped base material containing a dielectric as a main component. The dielectric layer 40 has a first surface 41 and a second surface 42 opposite to the first surface 41. The first surface 41 is parallel to the XY plane. The second surface 42 may be parallel to the XY plane, but may be non-parallel. That is, in the schematic cross-sectional view (YZ plane) in FIG. 2, the dielectric layer 40 shows a constant thickness, that is, a rectangular shape, but is not limited to this. The dielectric layer 40 may have a surface whose cross section is non-parallel to the first surface 41, such as a triangle or a trapezoid. Further, the dielectric layer 40 may be a dielectric lens having a shape such as a plano-convex shape or a plano-concave shape, and in this case, the second surface 42 may include a curved surface. As described above, the dielectric layer 40 has a distribution in its thickness, so that the directivity of the antenna can be adjusted according to a desired specification. The aspect in which the dielectric layer 40 has a thickness distribution is not limited to FIG. 2, and can be applied not only in FIG. 2 but also in the description of FIG. 3 described later. Further, the dielectric layer 40 may be, for example, a dielectric substrate or a dielectric sheet. Examples of the material of the dielectric layer 40 include glass such as quartz glass, ceramics, a fluororesin such as polytetrafluoroethylene, a liquid crystal polymer, and a cycloolefin polymer, but the material is not limited thereto. A conductor layer 43 is provided on the surface 41, which is one surface of the dielectric layer 40.

The conductor layer 43 is a planar layer whose surface is parallel to the XY plane. The conductor layer 43 may be, for example, a conductor sheet, a conductor substrate, or a material having a non-uniform thickness and a distribution. Examples of the conductor material used for the conductor layer 43 include, but are not limited to, silver and copper. Further, the conductor layer 43 may be arranged in a mesh-like pattern so that a part of the dielectric layer can be seen. By doing so, for example, when glass or resin having high transparency to visible light is used as the dielectric layer 40, the slot array antenna 101 having a mesh-like pattern can be made to appear transparent or translucent. can. Here, the term "transparent" means, for example, a state in which a transmittance of 90% or more can be obtained in visible light. As the shape of the mesh, various shapes can be applied as long as the coplanar line can be electrically connected, and the shape is not particularly limited, and the portion where the conductor layer 43 is made into a mesh shape may be a part or the whole.

The coplanar line 30 is an example of a power feeding unit, and is a flat transmission line formed on the conductor layer 43. The coplanar line 30 has a pair of slots 34, 35 running in parallel in the Y-axis direction, and a central conductor 31 sandwiched between the pair of slots 34, 35 and extending in the Y-axis direction. The outer conductor region of the pair of slots 34, 35 of the conductor layer 43 functions as the ground conductor 45. The coplanar line 30 has one end 32 connected to a branch point (branch point 36) to the coplanar lines 10 and 20 and the other end connected to an external device (not shown) such as an amplifier. Has an end 33 of the. The other end 33, which serves as the feeding end, is located at the edge of the dielectric layer 40 and the conductor layer 43.

The coplanar line 10 is an example of the first coplanar line, and is a flat transmission line formed in a T shape in a plan view of the conductor layer 43. The coplanar line 10 has a first line extending in the X-axis direction and a second line extending in the Y-axis direction. The coplanar line 10 is sandwiched between a pair of slots 16 and 17 running in parallel in the X-axis direction, a pair of slots 18 and 19 running in parallel in the Y-axis direction, and slots 16 to 19 and extends in a T shape. It has a central conductor 11.

In the slot array antenna 101 shown in FIG. 1, the slots 16 to 19 may have different widths, and by doing so, matching with the antenna impedance and matching with the line impedance are possible. Become. It should be noted that not only slots 16 to 19, but also slots 26 to 29 of the coplanar line 20 and slots 34 and 35 of the coplanar line 30 are included so that at least one or more of these slots have different widths. , The above impedance matching may be performed.

The outer conductor region of slots 16 to 19 of the conductor layer 43 functions as a ground conductor 45. The coplanar line 10 has an end portion 12 connected to the branch portion 36, an end portion 13 connected to the slot 51, and an end portion 14 connected to the slot 52. The end portion 12 is an example of the first end portion, and the ends 13 and 14 are examples of the second end portion. The coplanar line 10 has one portion between the end portion 12 and the end portions 13 and 14 that serves as a branch point to the slots 51 and 52 (branch portion 15).

The coplanar line 20 is an example of a second coplanar line, and is a flat transmission line formed in a T shape in a plan view of the conductor layer 43. The coplanar line 20 has a third line extending in the X-axis direction and a fourth line extending in the Y-axis direction. The coplanar line 20 is sandwiched between a pair of slots 26 and 27 running in parallel in the X-axis direction, a pair of slots 28 and 29 running in parallel in the Y-axis direction, and slots 26 to 29, and extends in a T shape. It has a central conductor 21.

The outer conductor region of slots 26 to 29 of the conductor layer 43 functions as a ground conductor 45. The coplanar line 20 has an end 22 connected to the branch 36, an end 23 connected to the slot 53, and an end 24 connected to the slot 54. The end portion 22 is an example of the first end portion, and the ends 23 and 24 are examples of the second end portion. The coplanar line 20 has one portion between the end portion 22 and the end portions 23 and 24, which serves as a branch point to the slots 53 and 54 (branch portion 25).

The slots 51 to 54 are slot-shaped antenna elements formed in the conductor layer 43, respectively. Each of the slots 51 to 54 functions as a half-wavelength dipole antenna. For example, _{when the wavelength at the operating frequency of the slots 51 to 54 is λ g} , the length d of each of the slots 51 to 54 in the longitudinal direction is about λ. _{Set to g} / 2. As a result, the antenna gain of the slot array antenna 101 is improved.

As described above, the coplanar lines 10 and 20 each have an end portion commonly connected to the branch point 36 connected to the coplanar line 30, which is the third coplanar line. That is, the coplanar lines 10 and 20 are branched from the common branch point 36 connected to the coplanar line 30 which is a power feeding unit, respectively. Therefore, since the coplanar lines 10 and 20 can be designed in different directions in which they extend, the degree of freedom in designing the orientations of the slots 51 to 54 connected to the ends of the coplanar lines 10 and 20 is high. can. Therefore, the slot array antenna 101 can be provided as a slot array antenna having an improved degree of freedom in designing the direction of directivity.

In the slots 51 to 54, the position of the coplanar line 30 which is the feeding portion may be adjusted so that all the phases of the high-frequency currents flowing in the slots 51 to 54 are aligned (so that the slots 51 to 54 are fed in the same phase). In the case of FIG. 1, the coplanar line 30 is located on the central axis of the H-shaped coplanar line formed by the coplanar lines 10 and 20. By feeding the slots 51 to 54 in the same phase, the antenna gain of the slot array antenna 101 can be improved.

In FIG. 1, slots 51 to 54 are linear slot antennas, respectively. However, at least one of the slots 51 to 54 may have other shapes, such as an elliptical shape, a bowtie shape, or a folded shape. By forming these shapes, it is possible to widen the bandwidth of the slot array antenna 101. In the case of a slot antenna other than a linear one, the extending direction in the shape is the longitudinal direction, and in the case of an elliptical slot antenna, for example, the long axis direction corresponds to the longitudinal direction.

It is preferable that some or all of the slots 51 to 54 are parallel to each other in terms of improving the antenna gain of the slot array antenna 101. In the case of FIG. 1, all of the slots 51 to 54 extend in the X-axis direction and are parallel to each other.

It is preferable that some or all of the slots 51 to 54 are located line-symmetrically with respect to one axis of symmetry in terms of improving the antenna gain of the slot array antenna 101. In the case of FIG. 1, when one virtual straight line passing through the branch point 36 is the axis of symmetry in a plan view, the slots 51 and 53 are axisymmetric with respect to the virtual straight line, and the slots 52 and 54 are the virtual straight lines. It is axisymmetric with respect to a straight line.

The coplanar lines 10 and 20 are connected at right angles to at least one slot (longitudinal direction) connected to the end of each of the coplanar lines 10 and 20 in terms of improving the antenna gain of the slot array antenna 101. preferable. In the case of FIG. 1, the coplanar line 10 is connected at a right angle to the slot 51 at the end 13, and is connected at a right angle to the slot 52 at the end 14, and the coplanar line 20 is connected at a right angle to the slot 53 at the end 23. It is connected and is connected at right angles to the slot 54 at the end 24.

When the slots 51 to 54 are located in each of the four regions divided by the two virtual straight lines orthogonal to each other at the branch point 36, the direction of directivity at which the antenna gain is maximized can be increased. For example, in FIG. 1, it is assumed that the first virtual straight line extending in the X-axis direction and the second virtual straight line extending in the Y-axis direction are orthogonal to each other at the branch point 36, that is, the branch point 36 is the origin. Assume an XY coordinate plane. In this case, slot 51 is located in the first quadrant, slot 53 is located in the second quadrant, slot 54 is located in the third quadrant, and slot 52 is located in the fourth quadrant. By arranging at least one slot-shaped antenna element in each of the four regions in this way, the directivity in the X-axis direction and the Y-axis direction is improved.

FIG. 3 is a side view illustrating another configuration example of the slot array antenna of the embodiment according to the present disclosure. As shown in FIG. 3, a conductor layer 44 may be provided on a part or all of the second surface 42, which is the other surface of the dielectric layer 40. In the case of FIG. 3, the conductor layer 44 is formed on the second surface 42 opposite to the first surface 41 and is shown as a planar conductor layer parallel to the XY plane, but the present invention is not limited to this. As described in FIG. 2, the conductor layer 44 may be a conductor layer in which the second surface 42 is arranged along a surface that is not parallel to the XY plane when the dielectric layer 40 has a distribution in its thickness. good. The conductor layer 44 may be, for example, a conductor sheet or a conductor substrate. Examples of the material of the conductor used for the conductor layer 44 include, but are not limited to, silver and copper. Further, the conductor layer 44 is not limited to the configuration in which the conductor having a uniform thickness is provided, and may be formed of a mesh like the other configuration examples of the conductor layer 43 in order to make the slot array antenna 101 transparent or translucent.

As shown in FIG. 3, the conductor layer 44 on the second surface 42 side is not connected to the conductor layer 43 on the first surface 41 side. That is, the conductor layer 44 is not conductively connected to the conductor layer 43 by a connecting conductor such as a via penetrating the dielectric layer 40. However, the conductor layer 44 may be electrically connected to the ground conductor 45. Such a conductor layer 44 is arranged so as to face at least one of the slots 51 to 54 with the dielectric layer 40 interposed therebetween. As a result, the conductor layer 44 functions as a reflective conductor that reflects radio waves radiated from at least one slot thereof, so that the directivity toward the positive side in the Z-axis direction is improved. Even if it is applied to the embodiment described later, the same effect can be obtained.

As described above, the non-feeding element (non-feeding conductor) such as the conductor layer 44 may be provided on a part of the second surface 42 of the dielectric layer 40. In that case, the non-feeding conductor is, for example, the position of at least one of the plurality of slots 51 to 54, preferably all the slots, when viewed from the normal direction (Z-axis direction) of the first surface 41. It may be provided in a predetermined region so that an antenna gain having a desired directivity can be obtained by adjusting the position. For example, when the non-feeding conductor is provided on a part of the second surface 42 of the dielectric layer 40, at least one of slots 51 to 54 is viewed from the normal direction (Z-axis direction) of the first surface 41. It is good to overlap with the slot. With this arrangement, the directivity toward the negative side in the Z-axis direction with reference to the dielectric layer 40 is enhanced, and the non-feeding conductor can function as a director. When the non-feeding conductor is provided on a part of the second surface 42 of the dielectric layer 40, the planar shape of the non-feeding conductor is not limited to a square, a rectangle, a polygon, a circle, an ellipse, or the like, and is arbitrary. It may be a shape that forms a region having an outer edge of. In that case, the free space wavelength of a radio wave for transmitting and receiving a lambda _0, the dielectric layer 40, the wavelength shortening rate at the wavelength lambda ₀ and k, and wavelength λ _{d =} k × λ _0. At this time, when the planar shape of the non-feeding conductor is, for example, a polygon including a square, the diagonal line of the polygon is λ _d / 2 or less, and when it is circular, the diameter of the circle is λ _d / 2 or less. In the case of an ellipse, the major axis of the ellipse _{may be λ d} / 2 or less.

Further, the non-feeding element (non-feeding conductor) such as the conductor layer 44 is arranged on the second surface 42 side with respect to the dielectric layer 40 away from the second surface 42 (in the −Z axis direction). Alternatively, it may be arranged on the first surface 41 side with respect to the dielectric layer 40 away from the conductor layer 43 (in the + Z axis direction). Further, when a non-feeding conductor such as the conductor layer 44 is arranged on the second surface 42 side with respect to the dielectric layer 40 away from the second surface 42, the non-feeding conductor is at least as described above. It may be arranged so as to overlap one slot, preferably all slots. When the conductor layer 44 functioning as a reflector (reflective conductor) is arranged on the second surface 42 side with respect to the dielectric layer 40 away from the second surface 42, the Z-axis direction with respect to the dielectric layer 40. Increases the directivity to the positive side of. As described above, when the conductor layer 44 is arranged on the second surface 42 side with respect to the dielectric layer 40 away from the second surface 42, it can function as a reflective conductor. When the first surface 41, the second surface 42, and the conductor layer 44 are arranged in parallel in the dielectric layer 40, the conductor layer 44 is larger than _{0 and at} a distance of λ 0/4 or less. It may be arranged away from the second surface 42. Further, in order to separate the dielectric layer 40 and the conductor layer 44 by a predetermined distance, for example, a spacer is provided at the end of the slot array antenna 101, or the slot array antenna 101 is fixed with a bracket or the like. , The distance may be maintained.

In FIG. 1, when the XZ plane is a plane parallel to the horizontal plane, if at least one of slots 51 to 54 extends in the X-axis direction, the Z-axis is used in transmitting and receiving vertically polarized radio waves. Directional antenna gain is improved. In the case of FIG. 1, the longitudinal direction of each of the slots 51 to 54 is parallel to the X-axis direction.

In FIG. 1, since the slots 51 to 54 extend along the X-axis direction, the slot array antenna 101 can transmit and receive radio waves of vertically polarized waves (polarized light in the Y-axis direction). The directivity of the vertically polarized radio waves is the side (side) of the slot array antenna 101 parallel to the longitudinal direction of the slot from at least one of the slots 51 to 54 in the plan view (XY plane) of the slot array antenna 101. It can be adjusted by the shortest distance (D1 or D2) to reach A or side B). Specifically, in FIG. 1, the shortest distances D1 and D2 are the ends (sides) of the conductor layer 43 parallel to the longitudinal direction of each slot from each slot in the direction perpendicular to the stretching direction of slots 51 to 54 in the XY plane. ) Corresponds to the shortest distance. Then, when the wavelength of the radio wave to be transmitted and received is λ, the directivity of vertically polarized waves can be adjusted by setting the distances of D1 and D2 to n · λ / 4 (n is an arbitrary value other than 0). Note that D1 and D2 may be different as long as the distances are n · λ / 4, but it is preferable that the distances are the same because the balance of the directivity of the antenna gain can be easily adjusted.

FIGS. 18 to 22 show the directivity of the YZ plane (vertical plane) and the XZ plane (horizontal plane) of the slot array antenna 101 in the case of n = 1, 2, 3 and 4 for the radio wave of vertically polarized wave of 28 GHz. It is a graph. 18 to 21 are shown in FIGS.
D1, D2 = λ / 4 = 2.7 mm (Fig. 18)
D1, D2 = 2λ / 4 = 5.4 mm (Fig. 19)
D1, D2 = 3λ / 4 = 8.1 mm (Fig. 20)
D1, D2 = 4λ / 4 = 10.8mm (Fig. 21)
(D1 = D2). In FIGS. 18 to 22, the full width at half maximum of the main beam in the YZ plane (vertical plane) is 32.2 °, 35.7 °, 57.1 °, and 53.6 °, respectively, and in the XZ plane (horizontal plane). The full width at half maximum of the main beam is 34.9 °, 37.3 °, 47.9 °, and 40.3 °, respectively. By changing the value of n (distance between D1 and D2) in this way, the directivity of the YZ plane (vertical plane) can be adjusted in particular.

FIG. 4 is a diagram illustrating the directivity of the slot array antenna 101 for a vertically polarized radio wave of 28 GHz, and shows the antenna gains of the YZ plane and the XZ plane, respectively. As shown in FIG. 4, the direction of directivity is directed to both the positive side and the negative side in the Z-axis direction, and 11.1 dBi is obtained as the peak value of the antenna gain. In FIG. 4, D1 = D2 = 4.5 mm.

FIG. 5 is a plan view illustrating the slot array antenna of the second embodiment according to the present disclosure. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The slot array antenna 102 shown in FIG. 5 differs from the slot array antenna 101 shown in FIG. 1 in the direction in which slots 51 to 54 extend.

In FIG. 5, when the XZ plane is a plane parallel to the horizontal plane, if at least one of the slots 51 to 54 extends in the Y-axis direction, the Z-axis is used in transmitting and receiving horizontally polarized radio waves. Directional antenna gain is improved. In the case of FIG. 5, the longitudinal direction of each of the slots 51 to 54 is parallel to the Y-axis direction.

The position of the coplanar line 30 may be adjusted so that all the phases of the high-frequency currents flowing in the slots 51 to 54 are aligned (so that the slots 51 to 54 are fed in the same phase). In the case of FIG. 5, the end portion 32 of the coplanar line 30 is connected to the branch point 36 at a position deviated from the central axis of the H-shaped coplanar line formed by the coplanar lines 10 and 20.

Further, not all of the slots 51 to 54 may extend in the same direction, and some slots and the remaining slots may extend in different directions. For example, some slots may extend in the X-axis direction and the remaining slots may extend in the Y-axis direction to accommodate both vertically and horizontally polarized waves. However, it is preferable that all the slots 51 to 54 extend in the same direction because the transmission / reception sensitivity of a predetermined polarized wave is increased.

Further, the coplanar line 30 may be linear, but it is bent so as to have a sufficient distance from the slot in order to prevent deterioration of characteristics such as directivity due to coupling due to proximity to the slot functioning as an antenna element. May have a portion. In the case of FIG. 5, the coplanar line 30 is bent so as to have a sufficient distance from the slot 51, and the characteristics such as directivity can be improved by bending as shown in the drawing as compared with the case of not bending.

FIG. 6 is a diagram illustrating the directivity of the slot array antenna 102 for a horizontally polarized radio wave of 28 GHz, and shows the antenna gains of the YZ plane and the XZ plane, respectively. As shown in FIG. 6, the direction of directivity is directed to both the positive side and the negative side in the Z-axis direction, and 10.4 dBi is obtained as the peak value of the antenna gain.

FIG. 7 is a plan view illustrating the slot array antenna of the third embodiment according to the present disclosure. FIG. 8 is a side view illustrating the slot array antenna of the third embodiment. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The slot array antenna 103 shown in FIGS. 7 and 8 differs from the slot array antenna 101 shown in FIG. 1 in the form of a feeding unit that supplies power to the coplanar lines 10 and 20. The coplanar line 30 of the slot array antenna 101 is contact-powered to the coplanar lines 10 and 20, whereas the strip conductor 130 of the slot array antenna 103 is non-contact power supply to the coplanar lines 10 and 20.

In FIG. 7, the strip conductor 130 is an example of a power feeding unit. The strip conductor 130 is provided on the surface 42 in the vicinity of the branch point 136. A microstrip line is formed by the strip conductor 130, the ground conductor 45 (a part of the conductor layer 43), and the dielectric layer 40. The strip conductor 130 extends in the Y-axis direction and faces the ground conductor 45 via the dielectric layer 40. The strip conductor 130 has one end 132 close to a branch point (branch point 136) to the coplanar lines 10 and 20 and the other end serving as a feeding end connected to an external device (not shown) such as an amplifier. It has an end 133. The other end 133, which is the feeding end, is located at the edge of the dielectric layer 40 and the conductor layer 43. In plan view, the strip conductor 130 intersects (preferably orthogonally) a linear line portion where the coplanar lines 10 and 20 extend from the branch point 136, respectively, and one end 132 protrudes from the branch point 136. With such a configuration, the strip conductor 130 can supply power to the coplanar lines 10 and 20 in a non-contact manner.

FIG. 9 is a plan view illustrating a slot array antenna including an LC filter. FIG. 10 is an enlarged view of FIG. When at least one LC filter is provided in at least one of the feeding unit, the first coplanar line, the second coplanar line, and the third coplanar line, it is possible to suppress a decrease in antenna gain due to noise. FIG. 9 shows a configuration in which the LC filter 60 is added to the coplanar line 30 (third coplanar line) which is a power feeding unit.

The LC filter 60 is, for example, a bandpass filter that passes a high frequency signal in a predetermined frequency band passing through a feeding unit or a coplanar line and blocks a high frequency signal in a frequency band other than the frequency band.

The LC filter 60 is a circuit having at least one inductance portion (L) and at least one capacitance portion (C), and is a filter formed by a planar pattern in the figure. By forming the LC filter with a flat pattern, it is possible to prevent the external dimensions of the slot array antenna in the Z-axis direction from becoming large due to the addition of the LC filter.

In the case of FIG. 10, the LC filter 60 has three inductance portions 61, 63, 65 and two capacitance portions 62, 64. The inductance portions 61 and 65 are formed by a pair of slots branched from the slots 34 and 35. The capacitance portions 62 and 64 are formed by slots that short-circuit between the slot 34 and the slot 35 via a bent portion. The inductance portion 63 is formed by a pair of gap portions inserted in series in the slots 34 and 35, respectively.

FIG. 11 is a diagram illustrating the filter characteristics of the LC filter 60 of FIG. As shown in FIG. 11, the LC filter 60 has an attenuation characteristic that blocks high-frequency signals in a frequency band other than the frequency band used by the slot array antenna 101.

The LC filter is not limited to the case where the form is formed by a flat pattern, and may be, for example, a filter circuit formed by a plurality of discrete elements, but the case where the LC filter is formed by a flat pattern. However, it is preferable in that the loss due to the connection point with the discrete element can be reduced.

FIG. 12 is a plan view illustrating the slot array antenna of the fourth embodiment according to the present disclosure. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The slot array antenna 104 shown in FIG. 12 has a different number of slots from the slot array antenna 101 shown in FIG. The slot array antenna 104 includes two slots 151 and 153.

That is, the number of slots connected to the respective ends of the first coplanar line and the second coplanar line may be at least one, and may be odd or even.

The slot array antenna 104 shown in FIG. 12 includes a dielectric layer 40, a plurality of coplanar lines 30, 110, 120, and two slots 151, 153.

The coplanar line 110 is an example of the first coplanar line, and is a flat transmission line formed in an L shape on the conductor layer 43. The coplanar line 110 has a first line extending in the X-axis direction and a second line extending in the Y-axis direction. The coplanar line 110 has a pair of slots that bend in an L shape and a central conductor 111 that is sandwiched between the pair of slots and extends in an L shape. The coplanar line 110 has an end 112 connected to the branch 36 and an end 113 connected to the slot 151. The end 112 is an example of the first end, and the end 113 is an example of the second end. The coplanar line 110 has no branch between the end 112 and the end 113.

The coplanar line 120 is an example of a second coplanar line, and is a flat transmission line formed in an L shape on the conductor layer 43. The coplanar line 120 has a first line extending in the X-axis direction and a second line extending in the Y-axis direction. The coplanar line 120 has a pair of slots that bend in an L shape and a central conductor 121 that is sandwiched between the pair of slots and extends in an L shape. The coplanar line 120 has an end 122 connected to the branch 36 and an end 123 connected to the slot 153. The end 122 is an example of the first end, and the end 123 is an example of the second end. The coplanar line 120 has no branch between the end 122 and the end 123.

FIG. 13 is a diagram illustrating the directivity of the slot array antenna 104 for a vertically polarized radio wave of 28 GHz, and shows the antenna gains of the YZ plane and the XZ plane, respectively. As shown in FIG. 13, the direction of directivity is directed to both the positive side and the negative side in the Z-axis direction, and 7.9 dBi is obtained as the peak value of the antenna gain.

FIG. 14 is a plan view illustrating the slot array antenna of the fifth embodiment. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The slot array antenna 105 shown in FIG. 14 has a different number of slots from the slot array antenna 101 shown in FIG. The slot array antenna 105 includes eight slots 91-98.

The slot array antenna 105 shown in FIG. 14 includes a dielectric layer 40, a plurality of coplanar lines 30, 70, 80, and eight slots 91 to 98. In the slot array antenna 105, the coplanar lines 70 and 80 are arranged in the Y-axis direction.

The coplanar line 70 is an example of the first coplanar line, and is a planar transmission line formed so as to include an H shape in the conductor layer 43. The coplanar line 70 has a pair of slots formed so as to include an H shape, and a central conductor 71 extending between the pair of slots. The coplanar line 70 includes an end 79 connected to the branch 36, an end 72 connected to the slot 91, an end 73 connected to the slot 92, and an end 74 connected to the slot 93. It has an end 75 connected to slot 94. The end portion 79 is an example of the first end portion, and the end portions 72 to 75 are an example of the second end portion. The coplanar line 70 has three points between the end portion 79 and the end portions 72 to 75 that serve as branch points to slots 91 to 94 (branch points 76, 77, 78).

The coplanar line 80 is an example of a second coplanar line, and is a planar transmission line formed so as to include an H shape in the conductor layer 43. The coplanar line 80 has a pair of slots formed so as to include an H shape, and a central conductor 81 sandwiched between the pair of slots and extending. The coplanar line 80 includes an end 89 connected to the branch 36, an end 82 connected to the slot 95, an end 83 connected to the slot 96, and an end 84 connected to the slot 97. It has an end 85 connected to slot 98. The end portion 89 is an example of the first end portion, and the end portions 82 to 85 are an example of the second end portion. The coplanar line 80 has three points between the ends 89 and the ends 82 to 85 that serve as branch points to slots 95 to 98 (branch points 86, 87, 88).

Further, the coplanar line 30 may be linear, but it is bent so as to have a sufficient distance from the slot in order to prevent deterioration of characteristics such as directivity due to coupling due to proximity to the slot functioning as an antenna element. You may be. In the case of FIG. 14, the coplanar line 30 is bent so as to have a sufficient distance from the slot 98, and the characteristics such as directivity can be improved by bending as shown in the drawing as compared with the case of not bending.

FIG. 15 is a plan view illustrating the slot array antenna of the sixth embodiment. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The slot array antenna 106 shown in FIG. 15 has different arrangement directions of the coplanar lines 70 and 80 from the slot array antenna 105 shown in FIG. In the slot array antenna 106, the coplanar lines 70 and 80 are arranged so as to be arranged in the X-axis direction.

FIG. 16 is a plan view illustrating a MIMO antenna including a plurality of slot array antennas. The description of the same configuration and effect as in the above-described embodiment will be omitted by referring to the above-mentioned description. The MIMO antenna 107 shown in FIG. 16 includes two slot array antennas 101A and 101B in which feeding portions are separately provided, and functions as a two-channel MIMO antenna. The slot array antennas 101A and 101B each have the same form as the slot array antenna 101 of FIG. 1, but other forms may be applied.

Further, although the slot array antennas of the first to sixth embodiments have been described with the configuration including branching points 36 and 136 branching into two coplanar lines, the present invention is not limited to this. For example, based on the slot array antenna 101 of the first embodiment, as shown in FIG. 17, the branch point 36 is divided into two coplanar lines, but the coplanar line 30 passes through the branch point 36 and goes straight through the extension coplanar. It may have a line 37. That is, as in the slot array antenna 108 of the seventh embodiment shown in FIG. 17, there may be a branch point 38 on the extension coplanar line 37, and two coplanar lines branching from the branch point 38 may be provided. In this case, the third coplanar line corresponding to the power feeding unit includes the extension coplanar line 37 that connects the pair (left and right) coplanar lines and the other pair of coplanar lines. In this example, the branch 36 is positioned as the center of the cross and has four T-shaped coplanar lines and eight linear slots. The LC filter may be arranged on the extension coplanar line 37 of the third coplanar line.

As described above, the case where the branch points 36 and 136 have a T-shaped line shape has been described, but in order to satisfy the specifications of the transmission / reception sensitivity and directivity of the antenna, the number of (linear) slots to be arranged is adjusted. The branching point may be a slot array antenna that includes not only a T-shape but also one or more cross-shaped line shapes. At this time, typically, there are N cross-shaped branch points and one T-shaped branch point, and each M (linear) line on the coplanar line branching from each branch point. When it has slots, it becomes a slot array antenna having (N + 1) × M (linear) slots. FIG. 17 shows the case where N = 1 and M = 4.

Although the slot array antenna has been described above according to the embodiment, the present invention is not limited to the above embodiment. Various modifications and improvements, such as combinations and substitutions with some or all of the other embodiments, are possible within the scope of the present invention.

This international application claims priority based on Japanese Patent Application No. 2018-077333 filed on April 13, 2018 and Japanese Patent Application No. 2018-229768 filed on December 7, 2018. Therefore, the entire contents of both applications will be incorporated into this international application.

10 Coplanar line (an example of the first coplanar line)
12, 22 First end 13, 14, 23, 24 Second end 15, 25 Branching point 16, 17, 18, 19, 26, 27, 28, 29 Slot 20 Coplanar line (second coplanar line) Example)
30 Coplanar line (example of power supply section)
34, 35 Slot 36 Branching point 37 Extension coplanar line 38 Branching point 40 Dielectric layer 41 One surface 42 The other surface 43,44 Conductor layer 45 Ground conductor 51-54 Slot 60 LC filter 70 Coplanar line (first coplanar line) Example)
72-75 Second end 76, 77, 78 Branch 79 First end 80 Coplanar line (an example of a second coplanar line)
82-85 Second Ends 86, 87, 88 Branches 89 First Ends 91-94 Slot 130 Strip Conductor (Example of Feeding Unit)
136 Branch points 101, 102, 103, 104, 105, 106 Slot array antenna 107 MIMO antenna 110 Coplanar line (an example of the first coplanar line)
120 Coplanar line (an example of the second coplanar line)

Claims (13)

A dielectric layer, a feeding portion, a first coplanar line formed on a conductor layer provided on one surface of the dielectric layer, and a second coplanar line formed on the conductor layer are provided.
The first coplanar line and the second coplanar line have a first end connected to or close to the power feeding portion, and at least one slot formed in the conductor layer, respectively. A slot array antenna having at least one second end to which the antenna is connected. The first coplanar line and the second coplanar line according to claim 1, wherein at least one of the second coplanar lines has at least one branch between the first end and the second end. Slot array antenna. The slot array antenna according to claim 1 or 2, wherein the longitudinal directions of the slots of the first coplanar line and the second coplanar line are parallel to each other. The slot array antenna according to any one of claims 1 to 3, wherein the slots of the first coplanar line and the slots of the second coplanar line are located line-symmetrically with respect to one axis of symmetry. The slot according to any one of claims 1 to 4, wherein the first coplanar line and the second coplanar line are connected at the second end at right angles to the longitudinal direction of the slot, respectively. Array antenna. The slot according to any one of claims 1 to 5, wherein the conductor layer has a side that is an end parallel to the longitudinal direction of the slot, and the shortest distances from the plurality of slots to the side are equal. Array antenna. The slot array antenna according to any one of claims 1 to 6, wherein at least one LC filter is provided in at least one of the feeding unit, the first coplanar line, and the second coplanar line. The slot array antenna according to claim 7, wherein the LC filter is a filter formed by a planar pattern. The slot array antenna according to any one of claims 1 to 8, wherein a conductor not connected to the conductor layer is provided on the other surface of the dielectric layer. The slot array antenna according to any one of claims 1 to 8, wherein a conductor that is not connected to the conductor layer is provided apart from the other surface of the dielectric layer. The slot array antenna according to any one of claims 1 to 10, wherein the feeding portion is a third coplanar line connected to the portion and formed on the conductor layer. The slot array antenna according to any one of claims 1 to 10, wherein the feeding portion is a strip conductor provided on the other surface of the dielectric layer in the vicinity of the portion. The slot array antenna according to any one of claims 1 to 12, wherein the slot is located at least one in each of four regions divided by two virtual straight lines orthogonal to each other at the said location.

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