JP2014045377A - Multi-beam reflect array - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-beam reflect array which can reflect an incident wave in a plurality of arbitrary directions.SOLUTION: A multi-beam reflect array has a plurality of elements arranged in a matrix form, in a first axial direction and a second axial direction, reflects an incident wave in a first desired direction by a plurality of elements belonging to a first region, and reflects the incident wave in a second desired direction by a plurality of elements belonging to a second region. In at least one of the first and second regions, the phase of a reflection wave reflected by a certain element is different from the phase of a reflection wave reflected by an element adjacent to the some element in the first axial direction by a predetermined value, and is equal to the phase of a reflection wave reflected by an element adjacent to a certain element in the second axial direction.

Description

  The disclosed invention relates to a multi-beam reflectarray or the like.

  Reflect arrays are often used to improve the propagation environment or area in mobile communication systems. When reflecting an incident wave, the reflect array can reflect not only in the specular reflection direction but also in a desired direction. A conventional reflectarray is described in Patent Document 1.

JP 2012-34331 A

  In the case of the conventional reflectarray, the incident wave, the specular reflected wave, and the reflected wave in the desired direction must be in the same plane, and in any direction different from the in-plane direction defined by the incident wave and the specular reflected wave. The incident wave cannot be reflected. Moreover, the incident wave cannot be reflected in a plurality of arbitrary directions. For this reason, the freedom degree of design will be restrict | limited. Furthermore, since the specular reflected wave and the reflected wave in the desired direction exist in the same plane, there is a concern that the reflected wave in the desired direction may deteriorate due to the specular reflected wave.

  An object of the disclosed invention is to provide a multi-beam reflectarray capable of reflecting an incident wave in an arbitrary plurality of directions.

The multi-beam reflectarray according to the disclosed invention is
Having a plurality of elements arranged in a matrix form in the first axial direction and the second axial direction, the incident wave is reflected in the first desired direction by the plurality of elements belonging to the first region, and the second A multi-beam reflectarray that reflects the incident wave in a second desired direction by a plurality of elements belonging to a region;
In at least one of the first and second regions, the phase of the reflected wave by a certain element differs from the phase of the reflected wave by an element adjacent to the certain element in the first axial direction by a predetermined value, and A multi-beam reflectarray having a phase equal to that of a reflected wave by an element adjacent to the certain element in the second axial direction.

  The disclosed invention can provide a multi-beam reflectarray capable of reflecting an incident wave in any of a plurality of directions.

Explanatory drawing for demonstrating the principle of a reflectarray. The figure which shows a mode that the element is formed by the mushroom structure. The figure which illustrates the alternative structure of an element. The enlarged plan view of a reflect array. The top view of a reflect array. The equivalent circuit diagram of the element by a mushroom structure. The figure which shows the relationship between the size Wx of the patch of the element by a mushroom structure, and a reflection phase. The top view of a reflect array in case vertical control is performed. The figure which shows an example of the patch for vertical control. The figure which shows another example of the patch for vertical control. The figure which shows another example of the patch for vertical control. The figure which shows generally the relationship between the incident wave and reflected wave of a reflect array. The figure which shows a mode that the center coordinate of each of the some element which comprises a reflect array exists in (m (DELTA) x, n (DELTA) y, 0). The figure which shows the relationship between phase difference (alpha) _mn and reflection direction ((theta) _r , (phi) _r ). The figure which shows the relationship between the reflection angles (theta) _r and (phi) _r at the time of fixing the deflection angle (theta) _i from the z-axis of an incident wave. The figure which shows an example of the reflection phase of the element which comprises a reflect array. The figure which shows the element for 1 row located in a line so that a reflect array may be comprised. The figure which shows the scattering cross section of a reflected wave. The figure which shows the reflection phase which each element implement | achieves. The figure which shows the simulation result when a radio wave enters and reflects on a reflect array (yz plane). The figure which shows the structure of the reflect array used for simulation. The figure which shows the relationship between a reflection direction and a phase difference. The figure which shows the reflection phase which each element | device which forms a reflect array implement | achieves. The figure which shows the simulation result when an electromagnetic wave injects into a reflect array and reflects ((theta) _r = 81 degree | times). The figure which shows the simulation result when an electromagnetic wave injects into a reflect array, and reflects ((phi) _r = 52 degree | times). The figure which shows the unit structure which comprises a multi-beam reflectarray. The figure which shows the reflection phase which each element | device which comprises a multi-beam reflectarray implement | achieves. The figure which shows gap size required in order for each element to implement | achieve a predetermined reflection phase. The figure which shows the reflection phase which each element | device which comprises a multi-beam reflectarray implement | achieves. The figure which shows the multi-beam reflectarray by a prior art example. The figure which shows the far radiation field of a reflected wave. The figure which shows the reflected wave by a multi-beam reflectarray.

  Embodiments will be described from the following viewpoints with reference to the accompanying drawings. In the figures, similar elements are given the same reference numbers or reference signs.

1． Reflect array
2． Phase difference control
2.1 One-dimensional phase difference control
2.2 Two-dimensional phase difference control
3． Multi-beam reflect array The classification of these items is not essential to the present invention, and the items described in two or more items may be used in combination as necessary. It may be applied to the matters described in the item (if there is no contradiction).

<1. Reflect Array>
First, a reflect array that is a premise of the disclosed invention will be described. FIG. 1 is an explanatory diagram for explaining the principle of a reflectarray. As shown in the figure, it is assumed that the phase of the reflected wave by each of the plurality of elements aligned on the ground plane gradually changes between adjacent elements. In the case of the illustrated example, the phase difference of the reflected wave by each adjacent element is 90 degrees. Since radio waves travel in a direction perpendicular to the equiphase surface (shown by broken lines), a reflective array is formed by arranging elements two-dimensionally while appropriately adjusting the reflection phase from each element. Thus, the incident wave can be reflected in a desired direction.

  FIG. 2 shows a mushroom structure that can be used as an element for a reflectarray. The mushroom structure includes a ground plate 51, vias 52, and patches 53. The ground plate 51 is a conductor that supplies a common potential to a large number of mushroom structures. Δx and Δy indicate an interval in the x-axis direction and an interval in the y-axis direction between vias in adjacent mushroom structures, respectively. Δx and Δy represent the size of the ground plate 51 corresponding to one mushroom structure. In general, the ground plate 51 is as large as an array of a large number of mushroom structures. The via 52 is provided to electrically short-circuit the ground plate 51 and the patch 53. The patch 53 has a length Wx in the x-axis direction and a length Wy in the y-axis direction. The patch 53 is provided in parallel to the ground plate 51 at a distance t, and is short-circuited to the ground plate 51 through the via 52. For simplicity of illustration, only two mushroom structures are shown in FIG. 2, but the reflect array has a large number of such mushroom structures in the x-axis and y-axis directions.

  In the case of the example shown in FIG. 2, each element constituting the reflect array has a mushroom structure. However, this is not essential for the embodiment. The reflect array may be formed of any element that reflects radio waves. For example, instead of a square patch, a ring-shaped conductive pattern (Fig. 3 (1)), a cross-shaped conductive pattern (Fig. 3 (2)), and a plurality of parallel conductive patterns (Fig. 3 (3 )) Etc. may be used. Further, in the mushroom structure, a structure (FIG. 3 (4)) without a via connecting the patch and the ground plate may be used. However, it is preferable to adopt a mushroom structure for the element as described above from the viewpoint of easily designing a small reflecting element.

  FIG. 4 shows an enlarged plan view of the reflectarray as shown in FIG. Shown are four patches 53 arranged in a line along the line p, and four patches 43 arranged along the line q adjacent to the line p. The number of patches is arbitrary. FIG. 5 shows a state in which a number of elements as shown in FIGS. 2 and 4 are aligned on the xy plane to form a reflectarray.

  FIG. 6 shows an equivalent circuit of the mushroom structure shown in FIG. 2, FIG. 4, and FIG. Capacitance C occurs due to a gap between the mushroom-structured patches 53 aligned along the line p in FIG. 4 and the mushroom-structured patches 53 aligned along the line q. Furthermore, an inductance L occurs due to the mushroom structure vias 52 arranged along the line p and the mushroom structure vias 52 arranged along the line q. Therefore, the equivalent circuit of the adjacent mushroom structure is a circuit as shown on the right side of FIG. That is, in the equivalent circuit, the inductance L and the capacitance C are connected in parallel. Capacitance C, inductance L, surface impedance Zs, and reflection coefficient Γ can be expressed as follows.

数式(1)において、ε₀は真空の誘電率を表し、ε_rはパッチ同士の間に介在する材料の比誘電率を表す。素子間隔は上記の例の場合、x軸方向のビア間隔Δxである。ギャップは隣接するパッチ同士の隙間であり、上記の例の場合、(Δx-Wx)である。Wxはx軸方向のパッチの長さを表す。すなわち、arccosh関数の引数は、素子間隔とギャップとの比率を表す。数式(2)において、μはビア同士の間に介在する材料の透磁率を表し、tはパッチ53の高さ(接地プレート51からパッチ53までの距離)を表す。数式(3)において、ωは角周波数を表し、ｊは虚数単位を表す。数式(4)において、ηは自由空間インピーダンスを表し、Φは位相差を表す。

In Equation (1), ε ₀ represents the dielectric constant of vacuum, and ε _r represents the relative dielectric constant of the material interposed between the patches. In the above example, the element interval is the via interval Δx in the x-axis direction. The gap is a gap between adjacent patches, and is (Δx−Wx) in the above example. Wx represents the length of the patch in the x-axis direction. That is, the argument of the arccosh function represents the ratio between the element spacing and the gap. In Equation (2), μ represents the magnetic permeability of the material interposed between the vias, and t represents the height of the patch 53 (distance from the ground plate 51 to the patch 53). In Equation (3), ω represents an angular frequency, and j represents an imaginary unit. In Equation (4), η represents free space impedance, and Φ represents a phase difference.

  FIG. 7 shows a relationship between the size Wx of the patch having the mushroom structure as shown in FIGS. 2, 4, and 5, and the reflection phase. In general, the reflection phase of the mushroom structure (element) becomes 0 at the resonance frequency, and the resonance frequency is determined by the capacitance C and the inductance L described above. Therefore, in the design of the reflectarray, it is necessary to appropriately set the capacitance C and the inductance L so that each element achieves an appropriate reflection phase. In the figure, solid lines indicate theoretical values, and those plotted with circles indicate simulation values by finite element method analysis. FIG. 7 shows the relationship between the patch size Wx and the reflection phase for each of four types of via heights or substrate thicknesses t. t02 represents a graph when the distance t is 0.2 mm. t08 represents a graph when the distance t is 0.8 mm. t16 represents a graph when the distance t is 1.6 mm. t24 represents a graph when the distance t is 2.4 mm. The via spacing Δx and Δy is 2.4 mm as an example.

  From the graph t02, it can be seen that the reflection phase can be around 175 degrees by setting the thickness to 0.2 mm. However, even if the patch size Wx changes from 0.5 mm to 2.3 mm, the difference in the reflection phase becomes 1 degree or less, and the value of the reflection phase hardly changes. From the graph t08, the phase can be around 160 degrees by setting the thickness to 0.8 mm. At this time, when the patch size Wx changes from 0.5 mm to 2.3 mm, the reflection phase changes from about 162 degrees to 148 degrees, but the change range is as small as 14 degrees. From the graph t16, when the thickness is 1.6 mm, the phase is 145 degrees or less, and when the patch size Wx changes from 0.5 mm to 2.1 mm, the reflection phase decreases only slowly from 144 degrees to 107 degrees. When the size Wx is larger than 2.1 mm, the reflection phase decreases rapidly.When the size Wx is 2.3 mm, the reflection phase is 54 degrees for the simulation value (circle) and 0 degree for the theoretical value (solid line) Reach. In the case of graph t24, when the patch size Wx changes from 0.5 mm to 1.7 mm, the reflection phase decreases only slowly from 117 degrees to 90 degrees, but when the size Wy is greater than 1.7 mm, the reflection phase When it decreases sharply and the size Wx is 2.3 mm, the reflection phase reaches -90 degrees.

  When forming an element with a mushroom structure as shown in FIGS. 2, 4, and 5, the patch size Wy in the y-axis direction is the same for all elements, and the patch size Wx in the x-axis direction varies depending on the location of the element. . However, it is not essential that the patch size Wy is common to all elements, and it is possible to design the patch size Wy to be different for each element. However, when designing a reflectarray using a mushroom structure in which the patch size Wy is the same for all elements, the design is simplified, and the patch size Wx in the x-axis direction can be determined according to the element location. . Specifically, one of the various via heights or substrate thicknesses t to be used in the design (e.g., t24) is selected, and the size of each of the multiple patches to be aligned is required at the position of the patch. It is determined according to the reflection phase. For example, when t24 is selected and the required reflection phase is 72 degrees at a certain patch position, the patch size Wx is about 2 mm. Similarly, the sizes of other patches are determined. Ideally, it is preferable that the patch size is designed so that the change of the reflection phase by the entire element group aligned in the reflect array is 360 degrees.

  By the way, in the structure shown in FIGS. 4 and 5, when a radio wave whose amplitude direction of the electric field E is in the x-axis direction is incident on the reflectarray, the reflected wave is in the direction in which the reflection phase is changed, that is, in the x-axis direction In the vertical or horizontal direction (y-axis direction). Controlling the reflected wave in this way is referred to as “horizontal control” for convenience. However, the present invention is not limited to horizontal control. For example, instead of the structure shown in FIG. 4 and FIG. 5, a reflect array is configured with a structure as shown in FIG. 8, and radio waves whose electric field amplitude direction is the y-axis direction are parallel to the electric field direction. In other words, it is possible to reflect in the vertical direction (y-axis direction). Controlling the reflected wave in this way is referred to as “vertical control” for convenience. When performing vertical control, the patch size and gap can be determined by several methods. For example, the element spacing Δy may be common and the individual patches may be asymmetric as shown in FIG. 9, or the individual patches may be symmetric and the element spacing may be different as shown in FIG. As shown in FIG. 11, the element spacing Δy may be common and the individual patches may be designed symmetrically. These are only examples, and the patch size and gap may be determined by any suitable method.

<2. Phase difference control>
FIG. 12 generally shows the relationship between the incident wave incident on the reflect array and the reflected wave reflected therefrom. In the example shown in the figure, the incident wave arrives in the directions of θ = θ _i and φ = φ _{i in} the (rθφ) polar coordinates, and the reflected wave advances in the directions of θ = θ _r and φ = φ _r . The origin corresponds to one element in the reflectarray. As described above, the element is typically a mushroom structure element, but the embodiment is not limited thereto. The incident unit vector u _i along the direction in which the incident wave travels can be written as follows.

u _i = (u _ix , u _iy , u _iz ) = (sinθ _i cosφ _i , sinθ _i sinφ _i , cosθ _i ) (5)
Reflecting unit vector u _r along the direction in which the reflected wave travels can be written as follows.

u _r = (u _rx , u _ry , u _rz ) = (sinθ _r cosφ _r , sinθ _r sinφ _r , cosθ _r ) (6)
As shown in FIG. 13, it is assumed that the center coordinates of each of the plurality of elements constituting the reflect array are (mΔx, nΔy, 0). However, m = 0,1,2, ... N _x, and n = 0, 1, 2, a ... N _y, N _x is the maximum value and N _y of m is the maximum value of n. The position vector r _mn of the mth element in the x-axis direction and the nth element in the y-axis direction (referred to as the mnth element for convenience) can be written as follows.

r _mn = (mΔx, nΔy, 0) (7)
In this case, the reflection phase α _mn to be realized by the mn-th element can be written as follows.

_{α mn = k 0 (r mn} · u i -r mn · u r) + 2πN ··· (8)
However, “·” represents an inner product of vectors. k ₀ represents the wave number (2π / λ) of the radio wave, and λ represents the wavelength of the radio wave. Substituting equations (5)-(7) into equation (8), we can write

_{α mn = k 0 (mΔx ×} sinθ i cosφ i + nΔy × sinθ i sinφ i -mΔx × sinθ r cosφ r over nΔy × sinθ _r sinφ _{r)
= K 0 mΔx (sinθ i cosφ} i over _{sinθ r cosφ r) + k 0} nΔy (sinθ i sinφ i -sinθ r sinφ r) ··· (9)
However, although 2πN = 0, generality is not lost. Note that α _mn can be set to an arbitrary value according to Equation (9), but from the viewpoint of constructing a reflectarray by repeatedly providing an element array for a certain period on the xy plane, adjacent elements The phase difference between them (“α _mn −α _m−1n ” or “α _mn −α _mn−1 ”) is preferably a divisor of 360 degrees (for example, 18 degrees).

Referring to Equation (9), the reflection phase α _mn to be realized by the mn-th element generally depends on Δx and Δy. In order for the reflect array to reflect radio waves in any direction (θ _r , φ _r ), in principle, the reflection phase α _mn of each element gradually changes in the x-axis direction and the y-axis direction. Also shows that it must change gradually. It is not impossible but not easy to arbitrarily change the reflection phase in both the x-axis direction and the y-axis direction.

  In the embodiment, the first term (term including Δx) and the second term (term including Δy) on the right side of Equation (9) are set to satisfy a certain condition, so that the reflection to be realized by each element. Make it easy to determine the phase. Such conditions are roughly classified into two types, and the first method is a method in which the reflection phase is changed only along one direction of the x-axis and the y-axis, and is not changed in the other direction. 1 One-dimensional phase difference control>. In the second method, the ratio between the first term (term including Δx) and the second term (term including Δy) on the right side of Equation (9) is maintained at a constant value, and the reflection phase difference between adjacent elements is 360 °. This is a divisor of degrees (2π radians) (more generally, a divisor of an integer multiple of 360 degrees), and will be described in <2.2 Two-dimensional phase difference control>.

<2.1 One-dimensional phase difference control>
<< Reflection phase depends only on Δx >>
First, in the first method, a method for changing the reflection phase only along the x-axis direction and not changing it in the y-axis direction will be described. In Equation (9), if (sinθ _i sinφ _i −sinθ _r sinφ _r ) multiplied by Δy is identically equal to 0, phase α _mn does not depend on Δy, and only Δx It becomes dependent. In this case, the phase α _mn gradually changes in the x-axis direction, but may be constant in the y-axis direction. In this way, by making the reflection phase to be realized by each element change in the x-axis direction but constant in the y-axis direction, a reflect array that reflects incident waves in any direction can be simplified. Can be realized.

When (sinθ _i sinφ _i −sinθ _r sinφ _r ) multiplied by Δy is equal to 0, the following equation holds.

sinθ _i sinφ _i = sinθ _r sinφ _r (10)
This indicates that equal to the magnitude of the y component of the size and the reflected wave reflected unit vector u _r of the y component of the incident unit vector u _i of the incident wave 12. That is, when the y components of the incident unit vector and the reflection unit vector are equal, the reflection phase to be realized by each element can be changed in the x-axis direction while being constant in the y-axis direction. Equation (10) can also be written as:

sinθ _r = sinθ _i sinφ _i / sinφ _r (11)
θ _r = arcsin (sinθ _i sinφ _i / sinφ _r ) (12)
Therefore, the deflection angle θ _r of the reflected wave from the z-axis can be uniquely determined based on the deflection angle φ _r of the reflected wave from the x-axis. In the present case, the reflection phase α _mn to be realized by the mn-th element can be written as follows.

α _mn = k ₀ mΔx (sinθ _i cosφ _i −sinθ _r cosφ _r )
= K ₀ mΔx [sinθ _i cosφ _i − (sinθ _i sinφ _i / sinφ _r ) × cosφ _r ] (13)
Accordingly, the reflection phase α _mn to be realized by the mn-th element is uniquely determined by the deflection angle φ _r from the x-axis of the reflected wave.
As an example, it is assumed that the deflection angle φ _i of the incident wave from the x-axis is 3π / 2 = 270 degrees. In this case, since sinφ _i = −1 and cosφ _i = 0, θ _r and α _mn can be written as follows.

θ _r = arcsin (-sinθ _i / sinφ _r ) (14)
α _mn = k ₀ mΔx [(sinθ _i / sinφ _r ) × cosφ _r ] (15)
FIG. 14 shows the relationship (the above formula (13)) between the reflection phase or phase difference α _mn and the reflection direction (θ _r , φ _r ). In the simulation, the distance Δx between elements in the reflect array is 4 mm, and the frequency of the radio wave is 11 GHz. In addition, the deflection angle of the incident wave from the z-axis is θ _i = 20 degrees, and the deflection angle of the incident wave from the x-axis is φ _i = 270 degrees. When the phase difference α _mn = 0, the deflection angle θ _r of the reflected wave from the z-axis is 20 degrees and the deflection angle φ _r from the x-axis is 90 degrees, which indicates specular reflection. As shown in the figure, when the phase difference α _mn increases from 0 to 45 degrees, the declination angle θ _r of the reflected wave from the z-axis gradually increases from 20 degrees to reach about 67 degrees, while reflecting The deflection angle φ _r from the x-axis of the wave gradually decreases from 90 degrees and reaches about 22 degrees.

FIG. 15 shows the relationship between the reflection angles θ _r and φ _r when the angle θ _i of the incident wave from the z-axis is fixed. In the illustrated example, the relationship between the reflection angles θ _r and φ _r when the incident angle θ _i is 10, 20, 45, and 70 degrees is shown. The angle of deviation φ _i of the incident angle from the x-axis is 270 degrees. In the case where the incident angle θi is 10 °, if a deflection angle theta _r from the z-axis of the reflected wave is 10 degrees, the polarization angle phi _r from the x-axis of the reflected wave is in the 90 degrees. This corresponds to specular reflection. In the case of the illustrated example, the state where the reflection angle φ _r is 90 degrees indicates specular reflection. For any incident angle θ _i , the reflection angle φ _r generally decreases as the reflection angle θ _r increases to approach 90 degrees.

FIG. 16 shows a state in which the reflection phase of the elements constituting the reflect array is determined using the relational expression as shown in Expression (13). The elements constituting the reflect array are aligned at intervals of 4 mm in the x-axis direction (Δx = 4 mm) and are also aligned at intervals of 4 mm in the y-axis direction (Δy = Δx = 4 mm). As described above, when Expression (10) is satisfied, the reflection phase α _mn to be realized by the element gradually changes in the x-axis direction, but may be constant in the y-axis direction. For this reason, in the illustrated example, the reflection phase changes by 18 degrees in the x-axis direction, but does not change in the y-axis direction.

  FIG. 17 shows a part of the elements arranged so as to realize the reflection phase of the element by the method shown in FIG. FIG. 17 shows only one row of elements arranged in the x-axis direction, but actually there is a similar element row also in the y-axis direction, forming a reflect array. In the simulation, an 80 mm × 80 mm reflect array was assumed, and the intensity of the reflected wave was calculated under the following conditions along with the periodic boundary conditions.

Radio frequency = 11GHz
Dielectric constant of the material interposed between the ground plane (ground plate) and the patch = 8.85 x 10 ^-12
Magnetic permeability of the material interposed between the ground plane (ground plate) and the patch = 1.26 x 10 ^-6
Incident wave incident direction (θ _i , φ _i ) = (20 degrees, 270 degrees)
Desired direction of reflected wave (θ _r , φ _r ) = (29 degrees, 45 degrees).

FIG. 18 shows the scattering cross section of the reflected wave. The desired direction is the direction of (θ _r , φ _r ) = (29 degrees, 45 degrees). The incident direction is (θ _i , φ _i ) = (20 degrees, 270 degrees). Therefore, the direction of specular reflection is (θ _i , φ _i ) = (20 degrees, 90 degrees). In FIG. 18, the scattering cross section (broken line) in the plane where the specular reflection occurs is compared with the scattering cross section (solid line) in the desired direction. As shown in the drawing, in the vicinity of θ _r = 29 degrees, the level in the desired direction is about 20 dB higher than the level in the specular reflection direction. Thus, according to the embodiment, a reflected wave can be strongly formed in any desired direction.

<< Reflection phase depends only on Δy >>
Next, in the first method, a method of changing the reflection phase only along the y-axis direction and not changing it in the x-axis direction will be described. In the above description, by satisfying Equation (10), the reflection phase α _mn to be realized by the element gradually changes in the x-axis direction, but is constant in the y-axis direction. Yes. However, the embodiment is not limited to this example, and conversely, the reflection phase α _mn to be realized by the element gradually changes in the y-axis direction, but may be constant in the x-axis direction. In that case, in Equation (9), the coefficient of Δx (sin θ _i cos φ _i −sin θ _r cos φ _r ) needs to be equal to zero. In this case, the following equation is established.

sinθ _i cosφ _i = sinθ _r cosφ _r・ ・ ・ (16)
This indicates that the y-component of the incident unit vector u _i of the incident wave and the x-component of the reflected unit vector u _r of the reflected wave is equal 12. When the x components of the incident and reflection unit vectors are equal, the reflection phase to be realized by each element can be changed in the y-axis direction while being constant in the x-axis direction. Equation (16) can also be written as:

sinθ _r = sinθ _i cosφ _i / cosφ _r・ ・ ・ (17)
θ _r = arcsin (sinθ _i cosφ _i / cosφ _r ) (18)
Therefore, the deflection angle θ _r of the reflected wave from the z-axis can be uniquely determined from the deflection angle φ _r of the reflected wave from the x-axis. In this case, the reflection phase α _mn to be realized by the mn-th element can be written as follows.

_{α mn = k 0 nΔy (sinθ} i sinφ i -sinθ r sinφ r)
= K ₀ nΔy [sinθ _i sinφ _i − (sinθ _i cosφ _i / cosφ _r ) × sinφ _r ] (19)
Accordingly, the reflection phase α _mn to be realized by the mn-th element is uniquely determined by the deflection angle φ _r from the x-axis of the reflected wave.

FIG. 19 shows a state in which the reflection phase of the elements constituting the reflect array is determined using the relational expression as shown in Expression (19). The elements constituting the reflect array are aligned at an interval of 4.5 mm in the x-axis direction and at an interval of 4.5 mm in the y-axis direction (Δy = Δx = 4.5 mm). As described above, when Expression (16) is satisfied, the reflection phase α _mn to be realized by the element gradually changes in the y-axis direction, but may be constant in the x-axis direction. For this reason, in the illustrated example, the reflection phase changes by 36 degrees in the y-axis direction, but does not change in the x-axis direction. In the simulation, the intensity of the reflected wave was calculated under the following conditions along with the periodic boundary conditions.

Radio frequency = 11GHz
Dielectric constant of the material interposed between the ground plane (ground plate) and the patch = 8.85 x 10 ^-12
Magnetic permeability of the material interposed between the ground plane (ground plate) and the patch = 1.26 x 10 ^-6
Incident wave incident direction (θ _i , φ _i ) = (10 degrees, 270 degrees)
Desired direction of reflected wave (θ _r , φ _r ) = (51.2 degrees, 90 degrees).

FIG. 20 shows the scattering cross section of the reflected wave on the yz plane. The desired direction is the direction of (θ _r , φ _r ) = (51.2 degrees, 90 degrees). The incident direction is (θ _i , φ _i ) = (10 degrees, 270 degrees). Therefore, the direction of specular reflection is (θ _i , φ _i ) = (10 degrees, 90 degrees). In the figure, the graph of E _theta indicating the level of theta direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. Graph E _phi indicates the level of the phi direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. It can be seen that a strong peak occurs in the desired direction of φ _r = 51.2 degrees.

Summarizing the above description of the case where the reflection phase depends only on Δx and the case where it depends only on Δy, the phase of the reflected wave by an arbitrary element (mn) of the plurality of elements constituting the reflect array is: It differs from the phase of the reflected wave by the element adjacent to the mn-th element in the first axis (x-axis or y-axis) direction by a predetermined value (in the above example, 18 degrees or 36 degrees), and the second axis ( It can be said that it is equal to the phase of the reflected wave by the element adjacent to the mn-th element in the y-axis or x-axis direction. Furthermore, the magnitude of the second axial component of the incident unit vector u _i is equal to the magnitude of the second axial component of the reflected unit vector u _r, and can be said.

<2.2 Two-dimensional phase difference control>
A second method for controlling the phase difference of the elements will be described. First, the difference between the reflection phase by the mn-th element and the reflection phase by an element adjacent to this element will be considered. The reflection phase difference Δα _x between elements adjacent in the x-axis direction can be written as follows.

Δα _x = α _mn −α _{m-1n
= K 0 mΔx (sinθ i cosφ} i over _{sinθ r cosφ r) + k 0} nΔy (sinθ i sinφ i -sinθ r sinφ r)
Over _{k 0 (m-1) Δx} (sinθ i cosφ i over _{sinθ r cosφ r) -k 0 nΔy} (sinθ i sinφ i -sinθ r sinφ r)
= K ₀ Δx (sinθ _i cosφ _i −sinθ _r cosφ _r ) (20)
The reflection phase difference Δα _y between elements adjacent in the y-axis direction can be written as follows.

Δα _y = α _mn −α _{mn-1
= K 0 mΔx (sinθ i cosφ} i over _{sinθ r cosφ r) + k 0} nΔy (sinθ i sinφ i -sinθ r sinφ r)
Over k ₀ mΔx (sinθ _i cosφ _i over _{sinθ r cosφ r) -k 0 (} n-1) Δy (sinθ i sinφ i -sinθ r sinφ r)
= K ₀ Δy (sinθ _i sinφ _i −sinθ _r sinφ _r ) (21)
In the embodiment that performs two-dimensional phase difference control,
Δα _x = γΔα _y = 2π / κ (22)
The relationship is used. Here, γ is a rational number, and κ is a divisor of 360, that is, an integer that divides 360. According to Equation (22), the value of the parameter is set so that the ratio between the reflection phase difference Δα _x by the elements adjacent in the x-axis direction and the reflection phase difference Δα _y by the elements adjacent in the y-axis direction becomes the predetermined value γ. Is set. Further, the reflection phase difference Δα _x between elements adjacent in the x-axis direction is set to be a divisor of 360 degrees (2π radians) (more generally, a divisor that is an integer multiple of 360 degrees). As a mere example, the predetermined value γ is 1 and κ is 10.

The relationship Δα _x = γΔα _y can be written as follows using equations (20) and (21).

k ₀ Δx (sinθ _i cosφ _i over _{sinθ r cosφ r) = γk 0} Δy (sinθ i sinφ i -sinθ r sinφ r) ··· (23)
From equation (22), Δα _y = 2π / (κγ), so the following equation is obtained.

k ₀ Δy (sinθ _i sinφ _i −sinθ _r sinφ _r ) = 2π / (κγ)
sinθ _r sinφ _r = −2π / (k ₀ Δyκγ) + sinθ _i sinφ _i (24)
Since Δα _x = 2π / κ, the following equation is obtained.

k ₀ Δx (sinθ _i cosφ _i −sinθ _r cosφ _r ) = 2π / κ
sinθ _r cosφ _r = −2π / (k ₀ Δxκ) + sinθ _i cosφ _i (25)
Dividing equation (24) by equation (25) yields:

φ _r = arctan ([− 2π / (k ₀ Δyκγ) + sinθ _i sinφ _i ] / [− 2π / (k ₀ Δxκ) + sinθ _i cosφ _i ]) (26)
According to Equation (26), the deflection angle φ _r of the reflected wave can be calculated from the incident deflection angles θ _i and φ _i . Furthermore, according to the equation (24) and (25), the deflection angle theta _i of the incident wave, the deflection angle phi _r of phi _i and the reflected wave, can be calculated deflection angle theta _r of the reflected wave.

Assuming that the deflection angle φ _i between the incident wave and the x-axis is φ _i = 3π / 2 = 270 degrees and the element spacing is Δx = Δy, Equation (26) can be written as follows.

φ _r = arctan ([− 2π / (k ₀ Δyκγ) −sinθ _i ] / [− 2π / (k ₀ Δxκ)])
= Arctan [1 / γ + (k ₀ Δxκsinθ _i ) / (2π)] (27)
When φ _i = 3π / 2 = 270 degrees, the following equation is obtained from equations (24) and (25).

θ _r = arcsin ([− 2π / (k ₀ Δyκγ) −sinθ _i ] / sinφ _r ] (28)
= Arcsin [−2π / (k ₀ Δxκcosφ _r )] (29)
As described above, since the embodiment uses the constraint or condition as expressed by Equation (22), the reflection phase difference Δα _x between the elements adjacent in the x-axis direction and the reflection phase difference between the elements adjacent in the y-axis direction. The ratio with Δα _y is a constant value γ, and Δα _x is a divisor of 360 degrees (more generally, a divisor of an integral multiple of 360 degrees). Since Δα _x is a divisor of 360 degrees (for example, 360 / κ _x ), a periodic boundary can be defined in the x-axis direction by κ elements aligned in the x-axis direction. Also, since Δα _y is a divisor of 360 degrees (for example, 360 / (κγ)) (more generally, a divisor that is an integer multiple of 360 degrees), it is determined by κγ elements aligned in the y-axis direction. The periodic boundary can be defined also in the y-axis direction. Therefore, a unit structure or a basic structure of a reflect array having a periodic boundary in both directions of the x-axis and the y-axis can be easily formed. By repeatedly forming this unit structure or basic structure in the x-axis direction and the y-axis direction, a reflect array having a desired size can be realized. This point is greatly different from a conventional reflect array in which a periodic boundary can be formed only in one direction by elements aligned in either the x-axis or y-axis direction. According to the embodiment, the incident wave can be reflected in an arbitrary desired direction by changing the phase difference in both directions of the x-axis and the y-axis.

FIG. 21 shows <2. The unit structure used for the simulation of the reflectarray which reflects an electromagnetic wave based on the principle demonstrated in the phase difference control> is shown. In the unit structure shown in the figure, 10 elements are aligned in the x-axis direction, and 10 elements are aligned in the y-axis direction. In the simulation, it is assumed that many such unit structures are provided on the xy plane. k indicates the direction of the incident wave, and E ₀ indicates the direction of the reflected wave. The following parameter values are used in the simulation.

Incident wave frequency = 11 GHz,
Incident wave incident direction (θ _i , φ _i ) = (10 degrees, 270 degrees),
Desired direction of reflected wave (θ _r , φ _r ) = (81 degrees, 52 degrees),
Spacing between elements Δx = Δy = 4.5 mm,
Ratio γ (= Δα _x / Δα _y ) = 1 of the reflection phase difference between elements adjacent in the x-axis and y-axis directions,
Number of divisions in one cycle κ = 10.

FIG. 22 is a simulation result showing a relationship between the direction (θ _r , φ _r ) of the reflected wave and the reflection phase difference (Δα = Δα _x = Δα _y ) between adjacent elements. The directions of incident waves are θ _i = 10 degrees and φ _i = 270 degrees, and the element spacing is Δx = Δy = 4.5 mm. When the desired directions of the reflected waves are θ _r = 81 degrees and φ _r = 52 degrees, it can be seen from FIG. 22 that the corresponding phase difference Δα is 36 degrees. In this case, since the phase difference in the entire range of 360 degrees is realized by 10 elements, the number of divisions κ in one period may be 10.

FIG. 23 shows reflection phases to be realized by the individual elements constituting the reflect array as shown in FIG. In this example, 10 elements are aligned in the _x -axis direction and 10 elements are aligned in the y-axis direction, and Δα _x = Δα _y = 36 degrees, γ = 1, and κ = 10.

FIG. 24 shows the electric field level of the reflected wave observed in the conical surface having an angle of 81 degrees with the z axis when radio waves are incident on the reflect array shown in FIG. As described above, θ _r = 81 degrees is the desired direction. Graph E _theta indicates the level of the theta direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. Graph E _phi indicates the level of the phi direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. In either case, a strong peak occurs in the direction of φ _r = 52 degrees, and the levels in the other directions are suppressed low. FIG. 25 shows the electric field level of the reflected wave observed in a plane whose declination from the x-axis is φ _r = 52 degrees when radio waves are incident on the reflect array shown in FIG. As described above, φ _r = 52 degrees is the desired direction. Graph E _theta indicates the level of the theta direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. Graph E _phi indicates the level of the phi direction component in the case of representing the electric field vector of the reflected wave (rθφ) polar. In both cases, a strong peak occurs in the vicinity of θ _r = 81 degrees, and the levels in the other directions are suppressed low. Therefore, it can be seen that the reflected wave can be strongly reflected in the desired direction by this reflect array.

<3. Multi-beam reflect array>
Next, consider a multi-beam reflectarray that reflects incident waves in multiple desired directions. The multi-beam reflectarray in the embodiment has a plurality of elements arranged in a matrix form in the x-axis direction and the y-axis direction, and the incident wave is transmitted in the first desired direction by the plurality of elements belonging to the first region. The incident wave is reflected in the second desired direction by the plurality of elements that reflect and belong to the second region. Each of the plurality of elements can be any element that reflects radio waves, but is typically an element of a mushroom structure. The method of reflecting the incident wave in the desired direction is <2. Any of the methods described in “Phase difference control” can be used. For example, both the first and second regions may reflect incident waves by <2.1 one-dimensional phase difference control>. In this case, both the first and second regions may reflect the incident wave by “a method of changing the reflection phase only in the x-axis direction (or the y-axis direction)”. Alternatively, the first region reflects the incident wave by “a method of changing the reflection phase only in the x-axis direction”, and the second region reflects the incident wave by “a method of changing the reflection phase only in the y-axis direction”. May be. Alternatively, both the first and second regions may reflect incident waves by <2.2 two-dimensional phase difference control>. Alternatively, the first region may reflect the incident wave according to <2.1 one-dimensional phase difference control>, and the second region may reflect the incident wave according to <2.2 two-dimensional phase difference control>.

FIG. 26 shows the unit structure or basic structure used for the simulation of the multi-beam reflectarray. In the unit structure shown in the figure, 10 elements are aligned in the x-axis direction, 10 elements are aligned in the y-axis direction, and the elements are arranged in a matrix form. Of the 10 columns arranged in parallel to the y-axis, the elements of 6 columns (from the 1st column to the 6th column) from the smaller x coordinate belong to the first region. Of the 10 columns arranged in parallel to the y-axis, the first column element with the smallest x coordinate and the seventh to tenth column elements belong to the second region. Therefore, the elements in the first column are shared by the first and second regions. In the simulation, it is assumed that many such unit structures are provided on the xy plane. k indicates the direction of the incident wave, and E ₀ indicates the direction of the reflected wave. The following parameter values are used in the simulation.

Incident wave frequency = 11 GHz,
Direction of incident wave (θ _i , φ _i ) = (10 degrees, 270 degrees),
First desired direction (θ _r1 , φ _r1 ) = (81 degrees, 52 degrees),
Second desired direction (θ _r2 , φ _r2 ) = (29 degrees, 45 degrees),
Spacing between elements Δx = Δy = 4.5 mm,
Ratio γ (= Δα _x / Δα _y ) = 1 of the reflection phase difference between elements adjacent in the x-axis and y-axis directions,
Number of divisions in one cycle κ = 10.

  FIG. 27 shows reflection phases realized by individual elements constituting the unit structure shown in FIG. Of the 10 columns arranged in parallel to the y-axis, the elements corresponding to the 6 columns (from the first column to the sixth column) from the smaller x coordinate belong to the first region. Of the 10 columns arranged in parallel to the y-axis, the first column element having the smallest x coordinate and the seventh to tenth column elements belong to the second region. In the case of the illustrated example, the first region reflects incident waves by <2.2 two-dimensional phase difference control>. For this reason, the reflection phase changes by 36 degrees in both directions of the x-axis and the y-axis. The second region reflects incident waves by <2.1 one-dimensional phase difference control (a method in which the reflection phase depends only on Δy)>. For this reason, the reflection phase changes by 36 degrees in the y-axis direction, but does not change in the x-axis direction.

  FIG. 28 shows gap sizes that can be used in realizing the reflection phases of the individual elements shown in FIG. The gap size is a dimension of a gap between adjacent element patches. Each element has a ground plane, a patch and a via between them.

  A unit beam structure shown in FIGS. 26 and 27 is repeatedly provided in the x-axis and y-axis directions, so that a multi-beam reflectarray having a desired size can be obtained. FIG. 29 shows a state in which two unit structures shown in FIGS. 26 and 27 are arranged in the x-axis direction and two in the y-axis direction. Actually, more than four unit structures may be arranged. In the example shown in the drawing, when attention is paid to two columns of elements (parts surrounded by a frame) that are boundaries between unit structures and adjacent to the boundary of the first region, two columns of elements along the y-axis direction ( It can be seen that the reflection phases with x coordinates of 40.5 and 45) are equal to each other. In the illustrated example, one column of elements belonging to the first region also belongs to the second region, and these element rows realize the same reflection phase. Therefore, in the unit structure in which the elements are arranged in 10 rows and 10 columns, the elements for 6 columns function as the first region that reflects the incident wave in the first desired direction, and the elements for 5 columns Functions as a second region that reflects in the second desired direction. By sharing one element row in the unit structure in both the first and second regions, it is possible to suppress reflection (side lobe or grating lobe) in an unnecessary direction other than the first and second desired directions, The reflection characteristics can be improved.

  In the example described with reference to FIGS. 26 to 29, one element row in the unit structure is shared by the first and second regions. However, this is not essential for the embodiment, and one or more element rows are shared. Any element row may be shared by the first and second regions. Furthermore, one or more element rows shared by the first and second regions form a boundary of the unit structure (that is, each of the first and second regions is formed by a plurality of continuous element rows. This is not essential, and the plurality of element rows forming the first and second regions may be continuous or discrete.

Further, the effects of the multi-beam reflectarray according to the embodiment will be described. First, consider a conventional multi-beam reflectarray that reflects incident waves in a first desired direction (α ₁ ) and a second desired direction (α ₂ ). However, in the present application, the “conventional example” is not necessarily a known technique, and the invention preceding the present invention corresponds to the “conventional example”. In the case of this multi-beam reflectarray, in order to reflect the incident wave in the second desired direction (α ₂ ) and the first period of the element array for reflecting the incident wave in the first desired direction (α ₁ ) The design cycle of the element arrangement is determined by a common multiple of the element arrangement with the second period.

FIG. 30 shows such a conventional multi-beam reflectarray. The illustrated multi-beam reflectarray has two or more groups of 12 (generally N) elements M1 to M12 arranged in the y-axis direction. Structures similar to these twelve (generally N) elements are provided repeatedly or periodically in the y-axis direction and the x-axis direction. Each of the elements is any element that reflects radio waves, and has a mushroom structure in the illustrated example. Radio waves arrive from the z-axis ∞ direction and are reflected by individual elements to form reflected waves. When each of n _k elements realizes a reflection phase that differs by Δφ = 360 / n _k degrees between adjacent elements, the reflection of θ _r = sin ⁻¹ [(λΔφ) / (2πΔy)] Radio waves are reflected at the corners. However, k is a wave number and is equal to 2π / λ. λ is the wavelength of the radio wave. Δy is an interval between adjacent elements. For example, regarding the reflection phases φ ₁₁ , φ ₁₂ , φ ₁₃ , and φ ₁₄ of four elements, the phase difference Δφ ₁ (= | φ _1i −φ _{1i + 1} |) between adjacent elements is 360/4 = 90 degrees. In this case, the radio wave is reflected at a reflection angle of α ₁ = sin ⁻¹ [(λΔφ ₁ ) / (2πΔy)]. Further, regarding the reflection phases φ ₂₁ , φ ₂₂ , φ ₂₃ , φ ₂₄ , φ ₂₅ , and φ ₂₆ of the _six elements, the phase difference Δφ ₂ (= | φ _2i −φ _{2i + 1} |) between adjacent elements is When 360/6 = 60 degrees, the radio wave is reflected at a reflection angle of α ₂ = sin ⁻¹ [(λΔφ ₂ ) / (2πΔy)].

As shown as “Design Phase” in FIG. 30,
Reflection phases of elements M1 and M2, the first value phi ₁₁ and phi ₁₂ relating reflection angle alpha ₁ of
Reflection phases of the element M3 and M4, the second value phi ₂₃ relating reflection angle alpha ₂ of and phi _24,
Reflection phases of elements M5 and M6, the first value phi ₁₁ and phi ₁₂ relating reflection angle alpha ₁ of
Reflection phases of the device M7 and M8, the second reflection angle alpha ₂ relates values phi ₂₁ and phi _22,
Reflection phases of the device M9 and M10 are the first value phi ₁₁ and phi ₁₂ relating reflection angle alpha ₁ of
Reflection phases of elements M11 and M12 are set to the second reflection angle alpha ₂ relates values phi ₂₅ and phi _26. In the case of the illustrated example, an element array including 12 elements reflects a first element group for reflecting radio waves in the first reflection angle α ₁ direction and a radio wave in the second reflection angle α ₂ direction. And a second element group. Therefore, when a radio wave is incident on such an element arrangement, a part is reflected in the direction of the reflection angle α ₁ by the first element group, and a part is reflected in the direction of the reflection angle α ₂ by the second element group. To do. Thereby, it is possible to realize a multi-beam reflectarray that reflects incident radio waves in the directions of α ₁ and α ₂ , respectively.

Thus, in the case of the multi-beam reflectarray according to the conventional example, the period of the structure to be reflected in the _first desired direction (α ₁ ) (number of first element groups = 4) and the second desired direction (α ₂ ) Is different from the period of the structure to be reflected (number of second element groups = 6). For this reason, it is necessary to form one period of the design with the value of the common multiple of both periods. In the example shown, one period of the design has a length of 12 elements. FIG. 30 shows 24 elements for two cycles of the design.

In the case of the illustrated example, in the first period (α ₂ , first period) with respect to the _second desired direction (α ₂ ), reflection phases having values of φ ₂₃ and φ ₂₄ are realized by the elements M3 and M4. The reflection phase having the same value as the reflection phase occurs in the fourth period (α ₂ , fourth period) related to the _second desired direction (α ₂ ) in the second period of the design. In the control for the second desired direction (α ₂ ), in addition to the radiation direction that appears when in-phase with the original spacing of 6 elements, the beam also appears in the radiation direction that appears when in-phase with the spacing of 18 elements. There is a problem that it occurs.

Since the phases are aligned even in a period other than the desired period, unnecessary lobes are generated in the specular reflection direction (0 degree) and other directions in addition to the desired direction (α ₁ = 45 degrees, α ₂ = 70 degrees). FIG. 31 shows the far radiation field of the reflected wave, and shows the intensity of the reflected wave together with the reflection angle. In the simulation, the first reflection angle α ₁ = 70 degrees and the second reflection angle α ₂ = 45 degrees. As shown in the figure, strong reflected waves (beams) are generated in directions of 70 degrees and 45 degrees. A strong beam is also generated in the 0 degree direction, which indicates the influence of specular reflection caused by the ground plane and the like.

The following formula is established between the control angle A, the element interval Δy, and the phase difference Δφ _A.

Δy ＝ Δφ _A・ λ / (2π ・ sin （A))
In the case where the phases are aligned at other than the desired period, for example, a phenomenon that the in-phase occurs when the element interval should be in-phase when Δy is 3Δy occurs. in this case,
sin ^-1 (Δφ _A・ λ / (2π ・ 3 Δy)
Unnecessary lobes are also generated in the direction of. Specifically, even if the design is performed with A = 70 degrees, side lobes are generated in the direction of 28 degrees.

In contrast, in the case of the multi-beam reflectarray according to the embodiment, not only the element group for the _first desired direction (α ₁ ) but also the element group for the second desired direction (α ₂ ). The phase difference in the Y-axis direction is the same as −36 degrees, and one period is formed by 10 elements. For this reason, a desired in-phase relationship can be established for all elements by configuring a multi-beam reflectarray using a periodic array. In other words, a multi-beam reflectarray can be constructed so that in-phase elements appear at an interval of a desired period = 10 elements for all elements. Furthermore, in the case of the multi-beam reflectarray according to the embodiment, the predetermined element array is shared by both the structure for the first desired direction (α ₁ ) and the structure for the second desired direction (α ₂ ). Is done.

  FIG. 32 shows a reflected wave by the multi-beam reflectarray according to the embodiment. As shown in the figure, reflected waves are strongly formed in the first and second desired directions.

  Thus, in the conventional method, since the common multiple of the period of each beam is used as the design period, synchronization can be achieved only in the design period. As a result, side lobes are generated in unnecessary directions, and according to the present invention, the common multiple of the period is not used as the design period, that is, the multi-beam is realized with the original period. For this reason, side lobes in unnecessary directions can be reduced.

  As described above, the embodiment in which radio waves are reflected by the reflect array has been described. However, the disclosed invention is not limited to the above embodiment, and those skilled in the art understand various modifications, modifications, alternatives, replacements, and the like. Will do. For example, the present invention may be applied to any suitable reflectarray that reflects incident waves in an arbitrary direction. Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. In addition, although specific mathematical formulas have been used to facilitate understanding of the invention, these mathematical formulas are merely examples unless otherwise specified, and other mathematical formulas that yield similar results may be used. Good. The classification of items in the above description is not essential to the present invention, and the items described in two or more items may be used in combination as necessary, or the items described in one item may be used in different items. It may apply to the matters described in (as long as there is no conflict). The boundaries between functional units or processing units in the functional block diagram do not necessarily correspond to physical component boundaries. The operations of a plurality of functional units may be physically performed by one component, or the operations of one functional unit may be physically performed by a plurality of components. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

Claims (7)

Having a plurality of elements arranged in a matrix form in the first axial direction and the second axial direction, the incident wave is reflected in the first desired direction by the plurality of elements belonging to the first region, and the second A multi-beam reflectarray that reflects the incident wave in a second desired direction by a plurality of elements belonging to a region;
In at least one of the first and second regions, the phase of the reflected wave by a certain element differs from the phase of the reflected wave by an element adjacent to the certain element in the first axial direction by a predetermined value, and A multi-beam reflectarray having a phase equal to that of a reflected wave by an element adjacent to the certain element in the second axial direction. Having a plurality of elements arranged in a matrix form in the first axial direction and the second axial direction, the incident wave is reflected in the first desired direction by the plurality of elements belonging to the first region, and the second A multi-beam reflectarray that reflects the incident wave in a second desired direction by a plurality of elements belonging to a region;
In at least one of the first and second regions, the phase difference (Δα ₁ ) of the reflected wave from each of the elements adjacent in the first axial direction and each of the elements adjacent in the second axial direction A multi-beam reflectarray in which a ratio to a phase difference (Δα ₂ ) of a reflected wave is a predetermined value, and Δα ₁ and Δα ₂ are divisors of integer multiples of 360 degrees (2π radians). Having a plurality of elements arranged in a matrix form in the first axial direction and the second axial direction, the incident wave is reflected in the first desired direction by the plurality of elements belonging to the first region, and the second A multi-beam reflectarray that reflects the incident wave in a second desired direction by a plurality of elements belonging to a region;
The phase of the reflected wave by an element in the first region differs from the phase of the reflected wave by an element adjacent to the certain element in the first axial direction by a predetermined value and the phase in the second axial direction. Equal to the phase of the reflected wave by an element adjacent to an element,
The second phase difference between the reflected waves from the elements each adjacent to the first axial direction of the region ([Delta] [alpha] ₁₎ and the phase difference between the reflected waves from the elements each adjacent to the second axial ([Delta] [alpha] ₂ ) Is a predetermined value, and Δα ₁ and Δα ₂ are divisors of integer multiples of 360 degrees (2π radians).   The element belonging to one or more predetermined columns among the plurality of elements arranged in the matrix form belongs to both the first region and the second region. The multi-beam reflectarray described in 1.   5. Each of the plurality of elements includes at least a ground plane and a patch, and a gap between the patches of the element in the first axial direction is gradually changed. Multi-beam reflect array.   6. The multi-beam reflectarray according to claim 1, wherein each of the plurality of elements has a mushroom structure. A predetermined number of elements aligned in the first axial direction together with a phase difference (Δα ₁ ) of reflected waves from each of the elements adjacent in the first axial direction, the first axis of the multi-beam reflectarray A structure corresponding to one period in the direction is formed, and the same number as the predetermined number aligned in the second axial direction together with the phase difference (Δα ₂ ) of the reflected wave from each element adjacent in the second axial direction A number of elements form a structure for one cycle of the second axial direction of the multi-beam reflectarray,
The multi-beam reflectarray according to claim 2 or 3.

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