JP4629641B2 - Array antenna device - Google Patents

Description

  The present invention relates to an array antenna apparatus using a planar antenna as an antenna element, and relates to an array antenna apparatus for microwave transmission / reception mainly used for communication, radar and the like.

  FIG. 8 is a plan view showing a configuration of a conventional array antenna apparatus using a patch antenna (planar antenna) as an antenna element as an example. In FIG. 8, the conventional array antenna apparatus is provided with an excitation antenna element (shaded) 1 and an excitation antenna element 2 adjacent to the excitation antenna element 1. In addition, electric power 3 from a plurality of (eight) excitation antenna elements 2 surrounding the excitation antenna element 1 is illustrated. Note that black dots in the antenna elements 1 and 2 represent feeding points.

  In general, in an array antenna apparatus, an increase in the mutual coupling amount affected by the power 3 radiated from the adjacent antenna element 2 is caused by deterioration of the active impedance of the excitation antenna element 1 and an amplifier at the subsequent stage of the excitation antenna element 1. Load the equipment. For this reason, in order to obtain the desired electrical characteristics of the array antenna device, reduction of the mutual coupling amount becomes a problem of the array antenna device.

  FIG. 9 is a diagram showing a configuration of another conventional array antenna apparatus (see, for example, Non-Patent Document 1). 9A is a perspective view, FIG. 9B is a schematic cross section, and FIGS. 9A and 9B are different in scale. Another conventional array antenna device includes an excitation antenna element 4, four rows of EBGs (Electromagnetic Band-Gap) 5, a dielectric substrate 6, and a ground plane 6a. As shown in FIG. 9, as an example of a technique for reducing mutual coupling, EBGs 5 are arranged to form a high impedance surface.

  Next, the operation of reducing mutual coupling will be described. FIG. 10 is a diagram showing an equivalent circuit of an EBG composed of an EBG capacitive component and an EBG inductive component. In FIG. 10, the equivalent circuit has an EBG patch portion converted into an equivalent circuit as an EBG capacitive component 7 and an EBG through hole portion converted into an equivalent circuit as an EBG inductive component 8 connected in parallel.

  Here, the impedance Z of the equivalent circuit shown in FIG. 10 is expressed by the following equation (1).

Z = jωL / (1-ω ² LC) Formula (1)

From equation (1), at the frequency _{f r} that satisfies ω ² = 1 / √LC, the impedance Z = ∞ (infinity), and to form a high impedance surface at EBG5 parts.

FIG. 11 is a diagram for explaining the operation of the EBG shown in FIG. In FIG. 11, an electric field component 9a perpendicular to the ground plane 6a and an electric field component 9b propagating through the EBG 5 and attenuated are shown. EBG5 in the frequency _{f r} of the above, to form a high impedance surface. In this case, for example, when the electric field component 9a passes EBG5, EBG5 attenuates the electric field only in the frequency _{f r,} obtain the effect of the electric field component 9b.

Fan Yang "Microstrip Antennas Integrated With Electromagnetic Band-Gap (EBG) Structures: A Low Mutual Coupling Design for Array Applications" IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 51, NO. 10, OCTOBER 2003

  In another conventional array antenna apparatus as described above, in order to reduce the amount of mutual coupling between the antenna elements, it is necessary to arrange the EBGs in a plurality of rows between the antenna elements. There is. However, there is a problem in that it is necessary to narrow the antenna element interval in order to ensure the coverage of the array antenna device. Furthermore, in consideration of ease of manufacturing, when an antenna element and an EBG are to be configured on the same dielectric substrate, the size of the EBG becomes larger between the antenna elements, and the EBG cannot be arranged between the antenna elements. was there.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to reduce manufacturability and cost with a simpler dielectric substrate configuration, and at the time of beam scanning at a wide angle. An array antenna apparatus capable of reducing the amount of mutual coupling is obtained.

  An array antenna apparatus according to the present invention is an array antenna apparatus having a planar antenna as an antenna element, the first antenna element, a second antenna element adjacent to the first antenna element, the first and A second antenna element is loaded on the top, a first dielectric substrate having a first dielectric constant, and a lower portion of the first dielectric substrate are loaded, and the first and second antenna elements are A first ground plane provided with slits at intervals between which the surface current does not propagate between the first and second antenna elements, and a lower part of the first ground plane, and a second relative dielectric constant. A second dielectric substrate having a second dielectric substrate, a second ground plane loaded below the second dielectric substrate, and the first and second antenna elements facing each other inside the second dielectric substrate. The first and second ground plates are loaded on the parts to be A plurality of electrical connections that are narrowly spaced with respect to the wavelength of the surface current propagating between the first and second antenna elements and arranged in a row parallel to the slits on both sides of the portion corresponding to the slits Through-holes are provided.

  The array antenna device according to the present invention has an effect that it is possible to reduce manufacturability and cost with a simpler dielectric substrate configuration and to reduce the mutual coupling amount at the time of beam scanning at a wide angle.

Embodiment 1 FIG.
An array antenna apparatus according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 is a diagram showing a configuration of an array antenna apparatus according to Embodiment 1 of the present invention. In the following, in each figure, the same reference numerals indicate the same or corresponding parts.

  1A is a plan view, and FIG. 1B is a cross-sectional view taken along line A-A ′ in FIG. The array antenna apparatus according to the first embodiment includes an excitation antenna element (planar antenna) (metal plate) 10a constituting the array antenna apparatus, and an excitation antenna element (planar antenna) (metal plate) adjacent to the excitation antenna element 10a. 10b, a dielectric substrate (material) 11 having a first relative dielectric constant, a dielectric substrate (material) 12 having a second relative dielectric constant, and a ground plane (metal plate) 13 provided with a slit S1; A ground plate (metal plate) 14 and a plurality of through holes 15 arranged in a row at a sufficiently narrow interval with respect to the wavelength of the surface current to be cut off are provided. The black dots in the excitation antenna elements 10a and 10b in the plan view represent feeding points, and power is supplied from a power source connected to the back surfaces of the excitation antenna elements 10a and 10b in the cross-sectional view.

  In the first embodiment, a dielectric substrate (first dielectric substrate) 11 is disposed below the antenna elements 10a and 10b of the array antenna apparatus having a planar antenna as an antenna element, and the wavelength of the surface current to be cut off. Dielectrics loaded with a ground plane (first ground plane) 13 of the antenna elements 10a and 10b provided with slits S1 that do not propagate, a ground plane (second ground plane) 14, and through holes 15 that are electrically connected to the ground planes 13 and 14. A body substrate (second dielectric substrate) 12 is arranged to cut off the surface current propagating between the antenna elements, thereby reducing the mutual coupling amount.

  Next, the operation of the array antenna apparatus according to the first embodiment will be described with reference to the drawings. FIG. 2 is a cross-sectional view showing a state of radiation when the excitation antenna element of the array antenna apparatus according to Embodiment 1 of the present invention is excited.

  First, FIG. 2 showing the state of radiation when the excitation antenna element 10a is excited is the same as FIG. 1B. In FIG. 2, radiation 16 to the space, spatial coupling 17 to the adjacent antenna element 10 b, an electric field (surface wave) 18 generated from the excitation antenna element 10 a and perpendicular to the ground plane 13, and orthogonal to the electric field 18. The surface current flowing through the path of the ground plane 13 on the side of the excitation antenna element 10a → the through hole 15 on the side of the excitation antenna element 10a → the ground plane 14 → the through hole 15 on the side of the excitation antenna element 10b → the ground plane 13 on the side of the excitation antenna element 10b (dotted line) (Arrow) 19 is shown. Among these, since the surface current 19 can obtain the effect of reducing the mutual coupling amount according to the first embodiment, the surface current 19 will be described here.

  In FIG. 2, the surface current 19 is orthogonal to the electric field (surface wave) 18, and propagates through the ground plane 13 toward the excitation antenna element 10b. In addition, when the base plate 13 is provided with slits S1 having an interval at which the surface current 19 does not propagate, the slits S1 appear to be in an open state (impedance is infinite (∞)).

  Here, the propagation path length considering the wavelength shortening of the dielectric substrate 11 and the dielectric substrate 12 followed by the surface current (broken arrow) 19 in FIG. 2 determines the phase amount of the surface current 19 as N · λ / 2 (N is If the distance is shifted by an odd number, λ is the wavelength of the propagating surface current 19), the surface current 19 propagates along a path as indicated by a dashed arrow in FIG. As a result, the phase of the surface current 19 is reversed, and the surface current 19 is not propagated to the excitation antenna element 10b, and the amount of coupling between the antenna elements is reduced.

  In addition, by configuring the dielectric substrate 12, the ground planes 13 and 14 and the through holes 15 with the substrate, the characteristics can be changed only by replacing the dielectric substrate 12, the ground planes 13 and 14 and the through hole 15 portions in the array state. The structure can be simplified and the manufacturing cost can be reduced.

  Further, by changing the relative permittivity and thickness of the dielectric substrate 12 and the arrangement and the number of arrangement of the through holes 15, it is possible to reduce the mutual coupling amount with respect to a desired frequency.

  It should be noted that the shape of the ground planes 13 and 14 (the length and thickness of the slit S1), the shape of the dielectric substrates 11 and 12 (whether the dielectric is divided, the relative dielectric constant, etc.), and the through hole 15 in the first embodiment. The shape (length, thickness, material, etc.) is not limited to the shape shown in FIGS.

Embodiment 2. FIG.
An array antenna apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 3 shows a configuration of the array antenna apparatus according to Embodiment 2 of the present invention.

  3A is a plan view, and FIG. 3B is a cross-sectional view taken along line B-B ′ in FIG. The array antenna apparatus according to the second embodiment includes an excitation antenna element (planar antenna) (metal plate) 10a constituting the array antenna apparatus, and an excitation antenna element (planar antenna) (metal plate) adjacent to the excitation antenna element 10a. 10b, a dielectric substrate (material) having a first relative dielectric constant (first dielectric substrate) 11, and a dielectric substrate (material) having a second relative dielectric constant (second dielectric substrate) 12, a ground plate (metal plate) (first ground plate) 13 provided with a slit (first slit) S1, and a ground plate (metal plate) provided with a slit (second slit) S2 (second plate) Ground plane) 14, ground holes 13 and ground planes 14, and a plurality of through holes (first through holes) 15 arranged in a row at sufficiently narrow intervals with respect to the wavelength of the surface current to be cut off, and a third relative dielectric Dielectric substrate (material) ) (Third dielectric substrate) 20, ground plane (metal plate) (third ground plane) 21, ground plane 14 and ground plane 21, and one row at a sufficiently narrow interval with respect to the wavelength of the surface current to be cut off A plurality of through holes (second through holes) 22 are provided. The black dots in the excitation antenna elements 10a and 10b in the plan view represent feeding points, and power is supplied from a power source connected to the back surfaces of the excitation antenna elements 10a and 10b in the cross-sectional view.

  Next, the operation of the array antenna apparatus according to the second embodiment will be described with reference to the drawings. FIG. 4 is a cross-sectional view showing a state of radiation when the excitation antenna element of the array antenna apparatus according to Embodiment 2 of the present invention is excited. FIG. 5 is an enlarged cross-sectional view of a portion C (center portion) in FIG.

  First, FIG. 4 and FIG. 5 show how the excitation antenna element 10a radiates when excited. 4 and 5, orthogonal to the electric field 18, the ground plane 13 on the side of the excitation antenna element 10a → the through hole 15 on the side of the excitation antenna element 10a → the ground plane 14 on the side of the excitation antenna element 10a → the slit S2 → on the side of the excitation antenna element 10b A surface current (broken arrow) 23 that flows through a path from the ground plane 14 to the through-hole 15 on the side of the excitation antenna element 10 b → the ground plane 13 on the side of the excitation antenna element 10 b is illustrated.

  Further, the electric field 18 is orthogonal, the ground plane 13 on the side of the excitation antenna element 10a → the through hole 15 on the side of the excitation antenna element 10a → the ground plane 14 on the side of the excitation antenna element 10a → the through hole 22 on the side of the excitation antenna element 10a → the ground plane 21 → excitation. The antenna element 10b side through hole 22 → excitation antenna element 10b side ground plate 14 → excitation antenna element 10b side through hole 15 → excitation antenna element 10b side ground plate 13 through the path of the wavelength of the surface current 23 A short surface current (white arrow) 24 is illustrated.

  Similar to the first embodiment, the surface current 23 is orthogonal to the electric field 18 radiated from the excitation antenna element 10a and propagates toward the excitation antenna element 10b. Further, the base plate 13 is provided with slits S <b> 1 having an interval at which the surface current 23 cannot propagate. The base plate 14 is also provided with slits S <b> 2 (<S <b> 1) having a sufficiently narrow interval than the wavelength of the surface current 23. At this time, the slit S2 appears to be in an open state (impedance is infinite (∞)).

  Here, the propagation path length considering the wavelength shortening of the dielectric substrate 11 and the dielectric substrate 12 followed by the surface current (broken arrow) 23 in FIG. 5 represents the phase amount of the surface current 23 as N · λ / 2 (N is If the distance is a shift distance (odd number, λ is the wavelength of the propagating surface current 23), the surface current 23 propagates along a path as indicated by a dashed arrow in FIG. 5.

  Further, as described above, the dielectric substrate 20 having the third relative dielectric constant below the ground plane 14, the ground plane 21, and the ground plane 14 and the ground plane 21 are electrically connected and sufficiently narrow with respect to the wavelength of the surface current to be cut off. A plurality of through holes 22 arranged in a row at intervals are loaded.

  Here, as described above, the surface current (white line arrow) 24 propagates to the ground plane 14 through the same path as the surface current 23, but the slit S2 provided in the ground plane 14 also appears to be open. At this time, the propagation path length considering the wavelength shortening of the dielectric substrate 11, the dielectric substrate 12 and the dielectric substrate 20 followed by the surface current 24 has a phase amount of N · λ / 2 (N is an odd number, λ Is the distance shifted), the surface current 24 propagates along a path indicated by a white line arrow in FIG. As a result, the phases of the surface current 23 and the surface current 24 are reversed, and the surface current 23 and the surface current 24 do not propagate to the excitation antenna element 10b, and the amount of coupling between elements at a plurality of frequencies is reduced.

  Further, the dielectric substrates 12 and 20, the ground plates 13, 14, 21 and the through holes 15 and 22 are formed of a substrate, so that the dielectric substrates 12 and 20, the ground plates 13, 14, 21 and the through hole 15 in the array state. The characteristics can be changed only by exchanging 22 parts, and the structure can be simplified and the manufacturing cost can be reduced.

  Further, by changing the relative permittivity and thickness of the dielectric substrates 12 and 20 and the arrangement and the number of arrangement of the through holes 15 and 20, it is possible to reduce the mutual coupling amount for a plurality of desired frequencies.

  In addition, the shape of the ground planes 13, 14, and 21 (the length and thickness of the slits S1 and S2) in the second embodiment, the shape of the dielectric substrates 11, 12, and 20 (whether the dielectric is divided, the relative dielectric constant) Etc.), and the shapes (length, thickness, material, etc.) of the through holes 15 and 22 are not limited to the shapes shown in FIGS.

Embodiment 3 FIG.
An array antenna apparatus according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 6 is a plan view showing the configuration of the array antenna apparatus according to Embodiment 3 of the present invention.

  In FIG. 6, the array antenna device according to the third embodiment is arranged with slits S1 and through holes 15 similar to those in the first embodiment so as to surround the excitation antenna element 10a and the excitation antenna element 10b. The excitation antenna elements surrounded by the slits S1 and the through holes 15 are two-dimensionally arranged. As a result, not only the excitation antenna element 10a and the excitation antenna element 10b but also the effect of reducing the coupling between elements around each excitation antenna element is obtained. Other configurations are the same as those in the first embodiment. Further, the black dots in the excitation antenna elements 10a and 10b in the plan view represent feeding points, and are fed from a power source (not shown) connected to the back surfaces of the excitation antenna elements 10a and 10b.

  In addition, by configuring the dielectric substrate 12, the ground planes 13 and 14 and the through holes 15 with the substrate, the characteristics can be changed only by replacing the dielectric substrate 12, the ground planes 13 and 14 and the through hole 15 portions in the array state. The structure can be simplified and the manufacturing cost can be reduced.

  Further, by changing the relative permittivity and thickness of the dielectric substrate 12 and the arrangement and the number of arrangement of the through holes 15, it is possible to reduce the mutual coupling amount with respect to a desired frequency.

  It should be noted that the shape of the ground planes 13 and 14 (the length and thickness of the slit S1), the shape of the dielectric substrates 11 and 12 (whether the dielectric is divided, the relative dielectric constant, etc.), and the through hole 15 in the third embodiment. The shape (length, thickness, material, etc.) is not limited to the shapes shown in FIGS.

Embodiment 4 FIG.
An array antenna apparatus according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 7 is a plan view showing a configuration of an array antenna apparatus according to Embodiment 4 of the present invention.

  In FIG. 7, the array antenna device according to the fourth embodiment includes a slit S2 and a through hole 22 in addition to the slit S1 and the through hole 15 similar to those of the second embodiment, and the excitation antenna element 10a and the excitation antenna element. The excitation antenna elements, which are arranged so as to surround the periphery of 10b and are surrounded by the slits S1 and S2 and the through holes 15 and 22, are two-dimensionally arranged. As a result, not only the excitation antenna element 10a and the excitation antenna element 10b but also the effect of reducing the coupling between elements around each excitation antenna element is obtained. Other configurations are the same as those of the second embodiment. Further, the black dots in the excitation antenna elements 10a and 10b in the plan view represent feeding points, and are fed from a power source (not shown) connected to the back surfaces of the excitation antenna elements 10a and 10b.

  Further, the dielectric substrates 12 and 20, the ground plates 13, 14, 21 and the through holes 15 and 22 are formed of a substrate, so that the dielectric substrates 12 and 20, the ground plates 13, 14, 21 and the through hole 15 in the array state. The characteristics can be changed only by exchanging 22 parts, and the structure can be simplified and the manufacturing cost can be reduced.

  Further, by changing the relative dielectric constant and thickness of the dielectric substrates 12 and 20, the arrangement and the number of arrangement of the through holes 15 and 20, there is an effect that the amount of mutual coupling can be reduced for a desired frequency and frequency band.

  In addition, the shape of base plates 13, 14, and 21 in Embodiment 4 (the length and thickness of slits S1 and S2, etc.), the shape of dielectric substrates 11, 12, and 20 (the presence or absence of dielectric division, the relative dielectric constant) Etc.), and the shapes (length, thickness, material, etc.) of the through holes 15 and 22 are not limited to those shown in FIGS. 3, 4, 5, and 7.

It is a figure which shows the structure of the array antenna apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the mode of radiation at the time of the excitation antenna element of the array antenna apparatus which concerns on Embodiment 1 of this invention excites. It is a figure which shows the structure of the array antenna apparatus which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the mode of radiation at the time of the excitation antenna element of the array antenna apparatus which concerns on Embodiment 2 of this invention excites. It is sectional drawing to which the C section of FIG. 4 was expanded. It is a top view which shows the structure of the array antenna apparatus which concerns on Embodiment 3 of this invention. It is a top view which shows the structure of the array antenna apparatus which concerns on Embodiment 4 of this invention. It is a top view which shows the structure of the conventional array antenna apparatus which uses a patch antenna as an antenna element as an example. It is a figure which shows the structure of another conventional array antenna apparatus. It is a figure which shows the equivalent circuit of EBG which consists of an EBG capacitive component and an EBG inductive component. It is a figure for demonstrating operation | movement of EBG shown in FIG.

Explanation of symbols

  10a excitation antenna element, 10b excitation antenna element, 11 dielectric substrate, 12 dielectric substrate, 13 ground plane, 14 ground plane, 15 through hole, 20 dielectric substrate, 21 ground plane, 22 through hole, S1 slit, S2 slit.

Claims (4)

An array antenna device having a planar antenna as an antenna element,
A first antenna element;
A second antenna element adjacent to the first antenna element;
A first dielectric substrate having the first and second antenna elements loaded thereon and having a first relative dielectric constant;
A slit that is loaded at the lower portion of the first dielectric substrate and has an interval between which the surface current does not propagate between the first and second antenna elements is provided in a portion where the first and second antenna elements face each other. A first ground plane;
A second dielectric substrate loaded at a lower portion of the first ground plane and having a second relative dielectric constant;
A second ground plane loaded under the second dielectric substrate;
The first and second antenna elements are loaded inside the second dielectric substrate so that the first and second antenna elements are opposed to each other, electrically connecting the first and second ground planes, and the first and second antennas. An array comprising a plurality of through-holes arranged in a row in parallel with the slits on both sides of the portion corresponding to the slits at a narrow interval with respect to the wavelength of the surface current propagating between the elements. Antenna device. An array antenna device having a planar antenna as an antenna element,
A first antenna element;
A second antenna element adjacent to the first antenna element;
A first dielectric substrate having the first and second antenna elements loaded thereon and having a first relative dielectric constant;
A first slit loaded in a lower portion of the first dielectric substrate and having an interval at which a surface current does not propagate between the first and second antenna elements, at a portion where the first and second antenna elements face each other. A first ground plane provided with
A second dielectric substrate loaded at a lower portion of the first ground plane and having a second relative dielectric constant;
A second ground plane loaded in a lower portion of the second dielectric substrate, provided with second slits in parallel with the lower portion of the first slit and having a smaller interval than the first slit;
The first and second antenna elements are loaded inside the second dielectric substrate so that the first and second antenna elements are opposed to each other, electrically connecting the first and second ground planes, and the first and second antennas. A plurality of first through-holes arranged in a row in parallel with the first slit on both sides of the portion corresponding to the first slit at a narrow interval with respect to the wavelength of the surface current propagating between the elements. ,
A third dielectric substrate loaded at a lower portion of the second ground plane and having a third dielectric constant;
A third ground plane loaded under the third dielectric substrate;
The first and second antennas are loaded inside and below the first through-holes in two rows inside the third dielectric substrate, electrically connecting the second and third ground planes. A plurality of second through-holes arranged in a row in parallel with the second slit on both sides of the portion corresponding to the second slit at a narrow interval with respect to the wavelength of the surface current propagating between the elements. An array antenna apparatus comprising: The array antenna device according to claim 1, wherein the antenna elements surrounded by the slits and the through holes are two-dimensionally arranged. The array antenna apparatus according to claim 2, wherein the antenna elements surrounded by the first and second slits and the first and second through holes are two-dimensionally arranged.

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