JPH10209735A - Phased array antenna - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a phased array antenna in which number and kinds of phase shifters are minimized and the directivity is switched with a simple control content. SOLUTION: Element antennas 1-8 whose number is 5 or over are arranged in a form of two rows or over and two columns or over respectively. Four element antennas 1-4, 5-8 adjacent in longitudinal and lateral directions are defined respectively to be element antenna groups, a phase shifter ϕ is inserted to each of the element antennas 1-8, the 4-element antenna group is defined to be an upper element antenna group. Then a phase shifter 2ϕ, whose phase shift amount is twice that of the phase shifter ϕ, is inserted to the element antenna group which is a component of the upper element antenna group. The inserted phase shifters are divided into four kinds A, B, C, D corresponding to the relative positions of the upper left, upper right, lower left, lower right element antennas or element antenna groups, and an identical phase control variable is given to the phase shifters of the same kind for the control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phased array antenna, such as a weather radar and a roadside beacon, which can switch its directivity discontinuously in multiple directions.

[0002]

2. Description of the Related Art A phased array antenna is an antenna whose directivity can be controlled by changing a relative phase of a feed signal of an element antenna. In order to change the phase, a phase shifter that achieves a predetermined phase shift amount is inserted into each element antenna.

[0003]

In the phased array antenna, in principle, the number of phase shifters required is equal to the number of each element antenna. Also, in order to finely adjust the directivity, the amount of phase shift of the phase shifter must be changed in small steps.
For this reason, it is necessary to arrange phase shifters having different phase shift amounts in series.

As a result, the number and types of phase shifters increase,
There is a problem that the content of the control for switching the directivity is also complicated. Therefore, an object of the present invention is to realize a phased array antenna in which the number and types of phase shifters can be reduced as much as possible and the directivity can be switched with simple control contents.

[0005]

According to the phased array antenna of the present invention, five or more element antennas are arranged in two or more vertical rows and two or more horizontal rows, and four vertically and horizontally adjacent four element antennas are elementally connected. When a fraction of less than 4 appears as an antenna group, the element antennas constituting the fraction are also considered as element antenna groups, and a phase shifter is inserted into each of the element antennas constituting each element antenna group, and four elements vertically and horizontally adjacent to each other are inserted. When an antenna group is grouped and a fraction less than 4 is obtained, the element antenna groups constituting the fraction are also grouped into an upper layer element antenna group, and each element antenna group configuring the upper layer element antenna group is , Insert a phase shifter with twice the phase shifter of the lower phase shifter, and perform the operation of stacking such layers so that all element antenna groups are included in a single upper layer element antenna. And the phase shifter to be inserted is associated with the relative positions of the element antenna or the element antenna group of upper left, upper right, lower left, lower right, and the four types A, B, The phase shifters of the same type are divided into C and D, and are controlled by giving the same phase control amount to the same type of phase shifter (claim 1).

The principle of operation of the above-described phased array antenna will be described. FIG. 1 shows eight element antennas 1, 2,.
８, 8 are arranged in four rows and two rows, and four element antennas 1, 2, 3, 4 and four element antennas 5,
6, 7, and 8 are element antenna groups. The numbering of the element antenna numbers is in the order of upper left, upper right, lower left, and lower right in the element antenna group.

FIG. 2 is a connection diagram of a phase shifter. A phase shifter having a phase shift amount φ is inserted into each of the element antennas 1, 2,. An upper phase shifter having a phase shift amount of 2φ is inserted. The type of the phase shifter corresponding to the upper left element antenna is A, the type of the phase shifter corresponding to the upper right element antenna is B, the type of the phase shifter corresponding to the lower left element antenna is C, and the lower right Let D be the type of phase shifter corresponding to the element antenna.

As for the type of the upper phase shifter, the type of the upper phase shifter corresponding to the upper left element antenna group is A, and the type of the upper phase shifter corresponding to the upper right element antenna group is B (lower left and lower). The lower right element antenna group does not exist in this example).
FIG. 3 is a diagram for explaining the relationship between the phase of each element antenna and the control of the phase shifter. FIG. 3A shows a phase of each element antenna when directivity is directed to the north direction, and a control method of the phase shifter at this time. To direct the directivity in the north direction, of the element antennas,
It is sufficient to delay the phases of 2, 5, and 6, so that the type C
(Hereinafter referred to as “phase shifter A” etc.) and phase shifter D are in a through state (no phase delay; use the symbol “0” hereinafter), and phase shifters A and B What is necessary is just to make it into a phase delay state (it uses a code | symbol 1 below).

FIG. 3B shows a phase of each element antenna when directivity is directed to the south and a method of controlling the phase shifter at this time. To direct the directivity in the south direction, among the element antennas, the element antennas 3, 4, 7, 8 arranged in the south side
, The phase shifters C and D may be set to state 1 and the phase shifters A and B may be set to state 0.

FIG. 3C shows a phase of each element antenna when directivity is directed to the east, and a control method of the phase shifter at this time. To direct the directivity in the east direction, of the element antennas, the phases of the element antennas 6 and 8 arranged on the east side are delayed by 3φ, and the phases of the element antennas 5 and 7 in the next row are shifted by 2φ.
It is only necessary to delay the phases of the element antennas 2 and 4 in the next row by φ, so that the phase shifters B and D are set to the state 1 and the phase shifters A and C are set to the state 1. It may be set to 0.

FIG. 3 (d) shows the phase of each element antenna when directivity is turned to the west and the method of controlling the phase shifter at this time. To direct the directivity in the west direction, of the element antennas, the phases of the element antennas 1 and 3 arranged on the west side are delayed by 3φ, and the phases of the element antennas 2 and 4 in the next row are set to 2φ.
It is only necessary to delay the phases of the element antennas 5 and 7 in the next row by φ, and for this purpose, the phase shifters A and C are set to state 1 and the phase shifters B and D are set to state 1. It may be set to 0.

FIG. 3 (e) shows the phase of each element antenna when directivity is directed toward the top, and the method of controlling the phase shifter at this time. To direct the directivity toward the top, it is necessary to make the phases of all the element antennas the same, and for this purpose, the states of all the phase shifters may be made the same (all 0s or all 1s). As described above, there are only four types of control signals corresponding to the phase shifters A, B, C, and D, so that the control content is simplified. Also, the number and types of phase shifters can be reduced as much as possible.

Next, the operation principle when the number of element antennas is a minimum of 5 will be described with reference to FIGS. FIG.
Arranges five element antennas 1, 2,..., 5 in two rows vertically and two rows horizontally.
3, 4 and one element antenna 5 are respectively formed as an element antenna group.

FIG. 5 is a connection diagram of a phase shifter. A phase shifter having a phase shift amount φ is inserted into each of the element antennas 1, 2,. An upper phase shifter having a phase amount of 2φ is inserted. The type of the phase shifter corresponding to the upper left element antenna 1 is A, and the upper right element antenna 2
Is B, the type of the phase shifter corresponding to the lower left element antenna 3 is C, and the type of the phase shifter corresponding to the lower right element antenna 4 is D. For the type of the upper phase shifter, the type of the upper phase shifter corresponding to the upper left element antenna group is A, and the type of the upper layer phase shifter corresponding to the upper right element antenna group is B (lower left and lower right). The element antenna group does not exist in this example).

FIG. 6 is a diagram for explaining the relationship between the phase of each element antenna and the control of the phase shifter. FIG. 6A shows a phase of each element antenna when directivity is directed to the north direction, and a control method of the phase shifter at this time. To direct the directivity in the north direction, of the element antennas, the phases of the element antennas 1, 2, 5 arranged on the north side may be delayed, and therefore, the phase shifters C and D are in the through state 0. The phase shifter A and the phase shifter B may be set to state 1.

FIG. 6B shows a phase of each element antenna when directivity is directed to the south and a method of controlling the phase shifter at this time. To direct the directivity in the south direction, of the element antennas, the phases of the element antennas 3 and 4 arranged on the south side may be delayed. For this purpose, the phase shifters C and D are set to state 1 and The phase shifter A and the phase shifter B may be set to the state 0.

FIG. 6C shows the phases of the respective element antennas when directivity is directed to the east and the method of controlling the phase shifter at this time. To direct the directivity in the east direction, the phase of the element antennas 5 arranged on the east side of the element antennas is set to 2φ.
It is only necessary to delay the phases of the element antennas 2 and 4 in the next row by φ, and for this purpose, the phase shifters A and C are set to the state 0, and the phase shifters B and D are set to the state 0. It may be set to 1.

FIG. 6 (d) shows the phase of each element antenna when directivity is turned to the west and the method of controlling the phase shifter at this time. In order to direct the directivity in the west direction, of the element antennas, the phases of the element antennas 1 and 3 arranged on the west side are delayed by 3φ, the phases of the middle element antennas 2 and 4 are delayed by 2φ, and the phases of the element antennas 5 arranged on the east side are delayed. May be delayed by φ. For this purpose, the phase shifters B and D may be set to the state 0, and the phase shifters A and C may be set to the state 1.

FIG. 6E shows the phase of each element antenna when directivity is directed to the top, and the method of controlling the phase shifter at this time. To direct the directivity toward the top, it is necessary to make the phases of all the element antennas the same, and for this purpose, the states of all the phase shifters may be made the same (all 0s or all 1s). Table 1 summarizes the relationship between the state and the directivity of the phase shifter of the present invention described above.
In Table 1, N, S, E, W, and UP in the upper row are north, respectively.
Shows directivity of south, east, west, and top.

[0020]

[Table 1]

FIG. 7 is a diagram showing a connection state of a conventional phase shifter, and corresponds to FIG. 5 which is a connection diagram of the phase shifter of the present invention. There is no concept of grouping by element antenna group,
The phase shifters a and b are inserted in series in the element antenna 1 respectively, the phase shifter is inserted in the element antenna 2 and the element antenna 3 is inserted.
The phase shifters d and e are inserted in series, respectively, the phase shifter f is inserted in the element antenna 4, and the phase shifters g and f are inserted in the element antenna 5 respectively. The phase shift amount of all phase shifters is φ.

Table 2 shows the relationship between the state of the phase shifter and the directivity in the conventional configuration.

[0023]

[Table 2]

When the present invention is compared with the conventional system, it has been found that, conventionally, a phase shifter is provided for each element antenna,
It is necessary to control the amount of phase shift of each phase shifter independently. Therefore, eight phase shifters are required, and eight types of control signals are required in principle. On the contrary,
In the present invention, there are two types of phase shifters, but the number of phase shifters is seven and the number of control signals is only four.

[0025]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. A case where the number of element antennas is 8 × 8 = 64 will be described. FIG. 8 is a diagram showing a state in which 64 element antennas are arranged at equal intervals and in a square shape. What shape, size,
The antenna may be a polarized or directional antenna, for example, a dipole antenna set up on a square reflector, a printed antenna or a slot antenna formed on a square substrate. In addition, a circularly polarized spiral antenna may be used.

FIGS. 9 to 11 are structural diagrams of the element antenna group and the upper layer element antenna group. FIG. 9 is a diagram illustrating four element antennas that are vertically and horizontally adjacent to each other among the element antennas 1, 2, 2,. FIG.
FIG. 11 is a diagram showing four vertically and horizontally adjacent element antennas as an upper layer element antenna group, and FIG. 11 is a diagram showing four vertically and horizontally adjacent upper element antennas as a further upper layer element antenna group.

FIG. 12 is a connection diagram of a phase shifter of the phased array antenna. Each of the element antennas, the element antenna group, and the upper layer element antenna group have a phase shift amount φ, 2φ,
A phase shifter having 4φ is inserted. The phase shifters to be inserted are classified into four types A, B, C, and D in association with the relative positions of the element antennas or the element antenna groups of upper left, upper right, lower left, and lower right (FIG. 9). -See FIG. 11). Further, a control device 1 that outputs four types of control signals according to types A, B, C, and D is provided.

Here, the phase shifter may be of any type, for example, a latching ferrite phase shifter using a ferrite or a phase shifter using a semiconductor such as a PIN diode or an FET. The control device 1 outputs four types of control signals necessary for the phase shifter to shift the phase. As described above, control signals having the contents shown in Table 1 are used.

According to such a configuration, the directivity can be switched discontinuously in multiple directions. As the signal switching means, any means can be used. For example, a predetermined code signal may be generated by a microcomputer, or a switch group may be provided to control on / off of the signal. The switching method may be manual or automatic, and if it is performed automatically, a phased array antenna whose directivity is automatically switched can be obtained. Automatic tracking can also be performed by adjusting the direction of the signal obtained from the target.

[0030]

As described above, according to the phased array antenna of the present invention, the number of phase shifters can be reduced.
Further, since it is not necessary to independently control the amount of phase shift of each phase shifter, the number of types of phase control signals can be reduced.

[Brief description of the drawings]

FIG. 1 shows eight element antennas 1, 2,.
And four element antennas 1, 2, 3, 4 and four element antennas 5, 6, 7, 8
FIG. 3 is a diagram showing a configuration in which each of them is an element antenna group.

FIG. 2 shows a phase shifter having a phase shift of φ inserted into each of the element antennas 1, 2,..., And 8, and an upper layer phase shifter having a double phase shift of 2φ is inserted for each element antenna group. It is a figure showing the connection state of a phase shifter.

FIG. 3 is a diagram for explaining the relationship among directivity, the phase of each element antenna, and the control of a phase shifter.

FIG. 4 shows five element antennas 1, 2,.
FIG. 4 is a diagram showing a configuration in which four element antennas 1, 2, 3, 4 and one element antenna 5 are arranged as element antenna groups, respectively, arranged in two rows and two horizontal rows.

FIG. 5 shows that a phase shifter having a phase shift φ is inserted into each of the element antennas 1, 2,..., And 5, and an upper layer phase shifter having a double phase shift 2φ is inserted for each element antenna group. It is a figure showing the connection state of a phase shifter.

FIG. 6 is a diagram illustrating the relationship between directivity, the phase of each element antenna, and control of a phase shifter.

FIG. 7 is a diagram showing a connection state of a conventional phase shifter in a phased array antenna.

FIG. 8 is a diagram showing a state where 64 element antennas are arranged in a square shape.

FIG. 9 is a diagram illustrating four element antennas that are vertically and horizontally adjacent to each other among the element antennas 1, 2,.

FIG. 10 is a diagram showing four vertically and horizontally adjacent element antennas as an upper layer element antenna group;

FIG. 11 is a diagram illustrating four upper-layer element antennas vertically and horizontally adjacent to each other as an upper-layer element antenna group.

FIG. 12 is a diagram showing a connection state of a phase shifter of a phased array antenna having 64 element antennas.

[Explanation of symbols]

 A, B, C, D Types of phase shifter φ Phase amount

Claims (1)

[Claims] 1. An element antenna having a number of 5 or more is arranged in two or more vertical columns.
Four element antennas arranged vertically and horizontally adjacent to each other are arranged in two or more rows, and when a fraction smaller than 4 appears, the element antennas constituting the fraction are also regarded as an element antenna group. A phase shifter is inserted into each of the element antennas constituting the antenna group, and the four element antenna groups that are vertically and horizontally adjacent are grouped together, and when a fraction less than 4 appears, the element antenna groups constituting the fraction are also grouped together in the upper layer. In addition to the element antenna group, a phase shifter with twice the phase shifter of the lower layer phase shifter is inserted for each element antenna group constituting the upper layer element antenna group, and the operation of stacking such layers is performed. , All the element antenna groups are repeatedly included up to one element antenna included in a single upper layer element antenna, and the inserted phase shifters are arranged in upper left, upper right, lower left, and lower right. The four types A, B, C, and D are divided according to the relative positions of antennas or element antenna groups, and the same type of phase shifter is controlled by giving the same phase control amount. A phased array antenna.