Phased array antenna assembly

Abstract

To provide a phased array antenna assembly in which a design that a requirement to a phase shift width of a phase shifter is softened, and a grating lobe does not occur, can be easily achieved.SOLUTION: A phased array antenna assembly comprises: a plurality of sub-arrays having a terminal for inputting or outputting a signal, and a plurality of phase shifters that shifts the signal transmitted to a plurality of antenna elements to be arranged and between each antenna element and the terminal; and a phase shift control circuit that controls a phase shift amount shifted by the phase shifter during the signal is transmitted to between each antenna element and the terminal. A phase shift amount of the signal transmitted to between each antenna element and the terminal, belonged to the same sub-array includes a difference in accordance with an electric wave that is emitted or received by the same sub-array. The phase shift amount of the signal is individually determined in each sub-array so as to be contained in a variable range of the phase shift amount of the signal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a phased array antenna device in which a plurality of antenna elements are arranged and their phases are controlled. [Background technology]

[0002] Conventionally, various phased array antenna devices have been proposed. Patent Document 1 discloses a phased array antenna device with improved beam scanning performance. This phased array antenna device includes a plurality of antenna elements, a distribution / combining circuit that distributes a transmission signal and combines a reception signal, and a phase shifter that shifts the phase of the transmission signal and the reception signal between the antenna elements and the distribution / combining circuit. In this phased array antenna device, the input VSWR for the phase shift value of each phase shifter is made uniform, so that the distribution amplitude value of the transmission signal supplied from the distribution / combining circuit to each phase shifter can be made to match the design value, thereby ensuring antenna performance according to the design value.

[0003] Patent Document 2 discloses a phase shifter that is miniaturized and has an increased variable phase range for use in an array antenna or the like.

[0004] 7(A) and 7(B) are conceptual diagrams showing an example of the operation of a conventional phased array antenna device. The phased array antenna device includes a terminal 11 for inputting or outputting a signal, a plurality of antenna elements 21, and a plurality of phase shifters 22.

[0005] Hereinafter, the amount of phase shift caused by the phase shifter 22 while a signal propagates between the antenna element 21 and the terminal 11 is represented as φ. In particular, the amount of phase shift caused by the phase shifter 22 while a signal propagates between the n-th antenna element (antenna element with element number n) 21 and the terminal 11 is represented as φ. n This is expressed as:

[0006] In this example, the phase shift amount φ nis equal to 30°×(n-1). As a result, the phased array antenna device emits a beam in a direction of angle θ according to the amount of phase shift φ. In this manner, the amount of phase shift φ is determined so that the phases of the radio waves from each antenna element 21 are aligned in the direction of angle θ.

[0007] 8(A) and 8(B) are conceptual diagrams showing an example of the operation of another conventional phased array antenna device. The phased array antenna device includes a terminal 11 for inputting or outputting a signal, and a sub-array 12 having a plurality of antenna elements 21 and a phase shifter 22.

[0008] Hereinafter, the amount of phase shift by the phase shifter 22 while a signal propagates between the n-th antenna element (antenna element with element number m, n) 21 of the m-th subarray 12 and the terminal 11 is defined as φ m,n This is expressed as:

[0009] In this example, the phase shift amount φ m,n is equal to 120° × (m-1). As a result, the phased array antenna device emits a beam in a direction of angle θ according to the amount of phase shift φ. In this way, the amount of phase shift φ of each antenna element 21 belonging to the same subarray 12 is equal. For this reason, the directivity of the subarray 12 does not change. The amount of phase shift φ of each subarray 12 is determined so that the phase of the radio waves from each subarray 12 is aligned in the direction of angle θ. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Publication No. 9-326625 [Patent Document 2] JP 2017-123560 A Summary of the Invention [Problem to be solved by the invention]

[0011] In phased array antenna devices as shown in Fig. 7(A) and Fig. 7(B), a phase shifter having a phase shift width of 360° is generally used. In particular, when constructing a large-scale phased array antenna device, a phase shifter having a phase shift width of 360° is essential. However, a phase shifter having a wide phase shift width is large in size and has a large loss. Therefore, in such phased array antenna devices, the degree of freedom in design is low. In particular, it is difficult to construct a phased array antenna device for the millimeter wave band where the spacing between antenna elements is narrow.

[0012] In the phased array antenna apparatus as shown in FIG. 8(A) and FIG. 8(B), phase shifters having a phase shift width of 360° are generally used, but the number of phase shifters can be reduced. Therefore, even if a phased array antenna apparatus is constructed using phase shifters having a wide phase shift width, the above-mentioned drawbacks can be mitigated. However, in such a phased array antenna apparatus, the interval at which a phase difference occurs in the excitation phase is the interval between the subarrays, so the occurrence of grating lobes depends not only on the interval between the antenna elements but also on the interval between the subarrays. Therefore, it is difficult to design a phased array antenna apparatus so that grating lobes do not occur.

[0013] On the other hand, a phase shifter having a narrow phase shift width can have a small size and a small loss.

[0014] An object of the present invention is to provide a phased array antenna apparatus in which the requirements for the phase shift width of a phase shifter are relaxed and a design in which no grating lobes occur can be easily performed. [Means for solving the problem]

[0015] The phased array antenna apparatus of the present invention comprises a plurality of subarrays each having a terminal for inputting or outputting a signal, a plurality of arranged antenna elements, and a plurality of phase shifters for shifting the phase of a signal propagating between the antenna elements and the terminal, and a phase-shift control circuit for controlling the amount of phase shift caused by the phase shifter while the signal is propagating between the antenna elements and the terminal, wherein the amount of phase shift of the signal propagating between each of the antenna elements belonging to the same subarray and the terminal has a difference according to the radio waves emitted or received by the subarray, and the amount of phase shift of the signal is determined separately for each of the subarrays so as to be within a variable range of the amount of phase shift of the signal. Effect of the Invention

[0016] According to the present invention, it is possible to realize a phased array antenna apparatus which relaxes the requirements for the phase shift width of the phase shifter and is easy to design so that no grating lobes occur. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a block diagram of a phased array antenna apparatus according to a first example of the embodiment. [Diagram 2] 2(A) and 2(B) are conceptual diagrams showing a first operation example of the phased array antenna apparatus according to the first example of this embodiment. [Diagram 3] 3(A) and 3(B) are conceptual diagrams showing a second operation example of the phased array antenna apparatus according to the first example of this embodiment. [Figure 4] FIG. 4 is a block diagram of a phased array antenna apparatus according to a second example of this embodiment. [Diagram 5] FIG. 5 is a diagram showing a simulation result of the directivity of the conventional phased array antenna apparatus shown in FIGS. 8(A) and 8(B). [Figure 6] FIG. 6 is a diagram showing a simulation result of the directivity of the phased array antenna apparatus according to this embodiment. [Figure 7]7(A) and 7(B) are conceptual diagrams showing an example of the operation of a conventional phased array antenna device. [Figure 8] 8(A) and 8(B) are conceptual diagrams showing an example of the operation of another conventional phased array antenna apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1 is a block diagram of a phased array antenna device according to a first example of an embodiment. The phased array antenna device includes a terminal 11 for inputting or outputting a signal, a plurality of subarrays 12, and a phase-shift control circuit 13. Each of the subarrays 12 has a plurality of antenna elements 21 and a plurality of phase shifters 22, and is similarly configured. The antenna elements 21 are arranged at equal intervals. The phase shifter 22 shifts the phase of a signal propagating between the antenna element 21 and the terminal 11. The phase-shift control circuit 13 controls the amount of phase shift φ by which the phase shifter 22 shifts the phase of the signal while the signal propagates between the antenna element 21 and the terminal 11.

[0019] The antenna elements 21 may be, for example, microstrip antennas arranged in a lattice pattern.

[0020] The phase shift width of the phase shifter 22 may be less than 360°, for example, 150°. The phase variable range of the phase shifter 22 may be continuous or discrete.

[0021] Each of the subarrays 12 further includes a first line 23 and a plurality of second lines 24. The second lines 24 are connected between one end of the first line 23 and the antenna element 21. For example, a distributor / synthesizer (not shown or not shown precisely) is used to branch the lines. The phase shifters 22 are inserted into the second lines 24 and connected in parallel with each other.

[0022] As will be described in detail below, the phase shift amount φ of the signal propagating between each antenna element 21 and terminal 11 belonging to the same subarray 12 has a difference according to the radio wave emitted or received by the subarray 12. In other words, when the subarray 12 emits or receives a certain radio wave, these phase shift amounts φ include those that are not equal to each other. Furthermore, the difference between these phase shift amounts φ changes according to the radio wave emitted or received by the subarray 12. The signal phase shift amount φ is determined separately for each subarray 12 so as to be included within the variable range of the signal phase shift amount φ.

[0023] As shown in FIG. 1, when a signal passes through one phase shifter 22 while propagating between the antenna element 21 and the terminal 11, the phase shift amount φ is equal to the phase shift amount of the signal by that phase shifter 22, and the variable range of the phase shift amount φ coincides with the phase variable range of that phase shifter 22.

[0024] The number of phase shifters 22 inserted in each of the second lines 24 is not limited to one, and may be more than one.

[0025] 2A and 2B are conceptual diagrams showing a first operation example of the phased array antenna apparatus according to the first embodiment. In this operation example, the amount of phase shift φ m,n The variable range of is -75° to 75°. m,n is equal to -45°+30°×(n-1). As a result, each subarray 12, and therefore the phased array antenna device, emits a beam in a direction of angle θ according to the phase shift amount φ. In this manner, the phase shift amount φ is determined separately for each subarray so that the subarray 12 forms a beam in the direction of angle θ and so that the phase shift amount φ is within its variable range.

[0026] Note that determining the amount of phase shift φ as in the conventional phased array antenna apparatus shown in Figures 7(A) and 7(B) does not mean determining the amount of phase shift φ separately for each subarray 12. This is because, when the amount of phase shift φ is determined as in the conventional phased array antenna apparatus shown in Figures 7(A) and 7(B), once the amount of phase shift φ of one subarray 12 is determined, the amount of phase shift φ of the other subarrays 12 is also uniquely determined.

[0027] In this operation example, the phase shift amount φ of the signal propagating between each antenna element 21 belonging to the same subarray 12 and the terminal 11 has a difference according to the beam emitted by the subarray 12. Specifically, the phase shift amount φ m,n and the phase shift φ m,n+1 The difference is 30°.

[0028] In this operation example, when the phase shifter 22 does not shift the phase of the signal, the signals input to the antenna elements 21 have the same phase. m,n -φ 1,1 is equal to the relative phase of the signal input to the nth antenna element 21 of the mth subarray 12 with respect to the signal input to the 1st antenna element 21 of the 1st subarray 12.

[0029] When the phase shifter 22 does not shift the phase of the signal, the signal input to one antenna element 21 and the signal input to another antenna element 21 may have different phases.

[0030] 2(A) and 2(B) show an example of operation when the phased array antenna device emits radio waves. The operation when the phased array antenna device receives radio waves corresponds to the reverse of the operation when the phased array antenna device emits radio waves.

[0031] For example, if the operation shown in Figures 2(A) and 2(B) is reversed, the phased array antenna device receives radio waves arriving from a direction of angle θ. m,nis equal to −45°+30°×(n−1). This ensures that signals propagating from each antenna element 21 belonging to the same subarray 12 to the terminal 11 have the same phase at the terminal 11.

[0032] 3(A) and 3(B) are conceptual diagrams showing a second operation example of the phased array antenna device according to the first example of this embodiment. The phase shift amount φ is determined separately for each subarray 12 so that the subarray 12 forms a focal beam and the phase shift amount φ is within its variable range. In this way, it is possible to form not only a beam directed toward a distant target, but also a focal beam that converges on the target.

[0033] 4 is a block diagram of a phased array antenna apparatus according to a second example of this embodiment. The phased array antenna apparatus according to the second example of this embodiment differs from the phased array antenna apparatus according to the first example of this embodiment in the following respects. That is, the phased array antenna apparatus according to the second example of this embodiment includes a subarray 12 having a first line 33 and a plurality of second lines 34. The second lines 34 branch off from the first line 33 and are connected to the antenna element 21. For example, a distributor or a coupler (not shown or not shown exactly) is used to branch off the line. The phase shifter 22 is inserted into the first line 33 and connected in series with each other.

[0034] As shown in FIG. 4, when a signal passes through multiple phase shifters 22 while propagating between the antenna element 21 and the terminal 11, the phase shift amount φ is equal to the sum of the phase shift amounts of the signal by those phase shifters 22, and the variable range of the phase shift amount φ coincides with the phase variable range formed by those phase shifters 22.

[0035] FIG. 5 is a diagram showing a simulation result of the directivity of the conventional phased array antenna device shown in FIG. 8(A) and FIG. 8(B). FIG. 6 is a diagram showing a simulation result of the directivity of the phased array antenna device according to the present embodiment. FIG. 5 and FIG. 6 show the directivity when 12 antenna elements are arranged in a straight line at equal intervals of 0.8 wavelengths and each antenna element is excited with equal amplitude using a frequency of 5.75 GHz. In addition, FIG. 5 and FIG. 6 show the directivity by the angle with respect to the direction perpendicular to the arrangement direction of the antenna elements. In addition, FIG. 5 and FIG. 6 show the directivity when the beam scanning angle is 0° and when the beam scanning angle is −10°.

[0036] As shown in Fig. 6, the phased array antenna apparatus according to this embodiment is capable of scanning a beam. Although not shown in the figure, it is also possible to scan the beam up to an angle of ±30° under the same conditions as above.

[0037] Furthermore, as shown in Fig. 5, in the conventional phased array antenna apparatus shown in Fig. 8(A) and Fig. 8(B), grating lobes occur in a direction of an angle of 10° at a beam scanning angle of -10°. On the other hand, in the phased array antenna apparatus according to this embodiment, no grating lobes occur at a beam scanning angle of -10°, as shown in Fig. 6. As can be seen from this result, in the phased array antenna apparatus according to this embodiment, it is easier to design the phased array antenna apparatus so that no grating lobes occur, compared to the conventional phased array antenna apparatus shown in Fig. 8(A) and Fig. 8(B).

[0038] According to this embodiment, the phase shift amount φ is determined separately for each subarray 12 so as to be included in the variable range. Therefore, the requirement for the phase shift width of the phase shifter 22 is relaxed. Therefore, a phased array antenna device can be constructed using a phase shifter having a narrow phase shift width, and therefore a small and low-loss phase shifter. In particular, even if a phase shifter having a narrow phase shift width is used, a large-scale phased array antenna device and even a distributed phased array antenna device can be constructed. In addition, a phased array antenna device for the millimeter wave band, which has a narrow spacing between antenna elements and requires a small phase shifter, can also be constructed. Since power loss is a particular problem in wireless power transmission, the effect of this embodiment is particularly remarkable.

[0039] Furthermore, the phase shift amount φ of signals propagating between each antenna element 21 belonging to the same subarray 12 and the terminal 11 has a difference according to the radio waves emitted or received by that subarray 12. Therefore, when emitting radio waves in the direction of a distant target, each subarray 12 changes its directivity according to the phase shift amount φ to form a beam. In other words, the interval at which a phase difference occurs in the excitation phase is the interval between the antenna elements 21. Therefore, the occurrence of grating lobes depends on the interval between the antenna elements 21, not the interval between the subarrays 12. This makes it easy to design a phased array antenna device so that grating lobes do not occur.

[0040] According to the first example of the present embodiment, the phase shifter 22 is inserted into the second line 24 and connected in parallel. Therefore, a signal propagating between the antenna element 21 and the terminal 11 does not pass through the phase shifter 22 connected to the antenna element 21 other than that antenna element 21. Therefore, loss in the phase shifter 22 is suppressed compared to the case where the phase shifters 22 are connected in series.

[0041] According to the second example of this embodiment, the antenna elements 21 are arranged at equal intervals, and the phase shifters 22 are inserted into the first line 33 and connected in series. Therefore, when scanning the beam toward a distant target, the amount of phase shift of the signal by each phase shifter 22 is equal to the amount of phase shift of the signal by the phase shifter 22 when the beam is not scanned. This makes it easier for the phase shift control circuit 13 to control the phase shifters 22.

[0042] Furthermore, the signal propagating between the antenna element 21 and the terminal 11 is cumulatively phase-shifted by the phase shifter 22. This further relaxes the requirement for the phase shift width of the phase shifter 22.

[0043] In a modified example, the sub-arrays 12 may have different configurations. Also, the antenna elements 21 do not have to be spaced equally apart.

[0044] Furthermore, the configurations of the first and second examples of this embodiment may be appropriately combined, that is, the subarray 12 may have both the phase shifters 22 connected in series and the phase shifters 22 connected in parallel.

[0045] The above description of the embodiment should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims, not by the above embodiment. Furthermore, the scope of the present invention is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0046] 11: Terminal 12: Subarray 13: Phase shift control circuit 21: Antenna element 22: Phase shifter 23,33: First track 24,34: Second track

Claims

1. A terminal for inputting or outputting a signal; a plurality of subarrays each including a plurality of arranged antenna elements and a plurality of phase shifters for shifting the phase of a signal propagating between the antenna elements and the terminal; a phase-shift control circuit that controls an amount of phase shift by the phase shifter while the signal is propagating between the antenna element and the terminal; a phase shift amount of the signal propagating between each of the antenna elements belonging to the same subarray and the terminal has a difference corresponding to a radio wave emitted or received by the subarray; A phased array antenna apparatus, wherein the amount of phase shift of the signal is determined separately for each of the subarrays so as to be within a variable range of the amount of phase shift of the signal.

2. Each of the subarrays comprises: The first line, a plurality of second lines connected between one end of the first line and the antenna element; The phased array antenna apparatus according to claim 1 , wherein the phase shifter is inserted in the second line.

3. The antenna elements are arranged at equal intervals, Each of the subarrays comprises: The first line, a plurality of second lines branching from the first line and connected to the antenna element; The phased array antenna apparatus according to claim 1 , wherein the phase shifter is inserted in the first line.

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