JP2010193052A - Array antenna device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an array antenna device capable of reducing the kinds of phase delay lines to be used and beam-tilting a main beam direction by a simple configuration. <P>SOLUTION: The array antenna device includes eight element antennas 1a-1h arrayed at equal intervals on a straight line and is capable of tilting the main beam direction from a broadside direction for a desired angle. The phase delay lines 3a-3c for delaying the phase of power supplied to the element antennas and outputting it are connected to the second to fourth element antennas among of the element antennas in one unit, setting four element antennas into one unit. The phase delay lines 3a-3c delay the phase so as to turn a phase difference from the adjacent element antenna to 2&pi;/4. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an array antenna apparatus including a plurality of element antennas, and more particularly to an array antenna apparatus capable of tilting a main beam direction from a broadside direction (hereinafter referred to as “beam tilt”).

FIG. 8 is a configuration diagram showing a general array antenna apparatus.
In FIG. 8, this array antenna apparatus includes eight element antennas 51a to 51h arranged on a straight line at equal intervals d. In addition, an axis along the arrangement direction of the element antennas 51a to 51h is an x axis, and a broad side direction (a direction perpendicular to the x axis) of the array antenna apparatus is a z axis.

Here, in the case where the main beam direction of the array antenna apparatus is beam tilted by a predetermined angle θ ₀ from the z-axis direction (broadside direction) to the x-axis direction, the following formula ( It is necessary to supply power so as to give the phase difference ΔP expressed by 1). In equation (1), k represents the wave number (k = 2π / λ) of the frequency at which the array antenna apparatus is operated.

ΔP = k × d × sin θ ₀ (1)

  In order to give the phase difference ΔP between the adjacent element antennas 51a to 51h, a phase shifter may be connected to the power supply circuit of each of the element antennas 51a to 51h. However, in general, the phase shifter is expensive, and requires a control circuit. Therefore, there is a problem that the configuration of the array antenna apparatus becomes complicated and the manufacturing cost increases.

  Therefore, in the conventional array antenna apparatus, the main beam direction is tilted in four specific directions by switching the RF switch without using a phase shifter (see, for example, Patent Document 1).

In addition, when the beam tilt angle in the main beam direction is fixed to a specific angle, a phase delay line is inserted into a part of the feed line, so that the above-described level can be achieved without using a phase shifter. A phase difference ΔP can be realized.
FIG. 9 is a block diagram showing an array antenna apparatus that beam tilts the main beam direction using a phase delay line.

  In FIG. 9, the array antenna apparatus includes eight element antennas 51a to 51h arranged on a straight line. The element antennas 51a to 51h are connected to a feed line 52 that feeds power to the element antennas 51a to 51h. Also, different types of phase delay lines 53a to 53g are inserted between the element antennas 51b to 51h and the feed line 52, respectively. The feed line 52 and the phase delay lines 53a to 53g constitute a feed circuit of the array antenna device.

Here, the phase delay line 53a gives a phase difference ΔP, the phase delay line 53b gives a phase difference 2ΔP, and hereinafter, the phase delay lines 53c, 53d, 53e, 53f, and 53g have a phase difference 3ΔP, 4ΔP, respectively. 5ΔP, 6ΔP, and 7ΔP are given.
Thereby, a phase difference ΔP can be given between the adjacent element antennas 51a to 51h, and the main beam direction of the array antenna apparatus can be tilted without using a phase shifter.

  However, in the array antenna apparatus of FIG. 9, although the structure for tilting the main beam direction can be realized with a relatively low cost and simple configuration, there are many types (here, seven types) of phases. There was a problem that it was necessary to prepare a delay line.

In order to solve the above problems, an array antenna apparatus as shown in FIG. 10 has been proposed.
FIG. 10 is another configuration diagram showing an array antenna apparatus that beam tilts the main beam direction using a phase delay line.

  In FIG. 10, the array antenna apparatus includes eight element antennas 51a to 51h arranged on a straight line. The element antennas 51a to 51h are connected to a feed line 52 that feeds power to the element antennas 51a to 51h. The feed line 52 is branched into two lines in three stages and connected to the element antennas 51a to 51h.

  Here, a phase delay line 53d that gives a phase difference 4ΔP is inserted into one of the lines branched at the first-stage branch point of the feed line 52. In addition, a phase delay line 53b that gives a phase difference 2ΔP is inserted into one of the lines branched at the branching point of the second stage of the feed line 52. In addition, a phase delay line 53 a that gives a phase difference ΔP is inserted into one of the lines branched at the third branch point of the feed line 52.

The feed line 52 and the phase delay lines 53a, 53b, and 53d constitute a feed circuit of the array antenna apparatus.
Thereby, a phase difference ΔP can be given between the adjacent element antennas 51a to 51h, and the main beam direction of the array antenna apparatus can be tilted without using a phase shifter.

JP 2008-060897 A

However, the prior art has the following problems.
In the array antenna apparatus of FIG. 10, although the type of phase delay line to be used can be reduced, it is necessary to configure the feed line in multiple stages and to insert a phase delay line at every branched stage. For this reason, there is a problem that the length of the feeder line becomes longer and the configuration becomes complicated.

  The present invention has been made to solve the above-described problems, and provides an array antenna apparatus capable of reducing the types of phase delay lines to be used and beam tilting the main beam direction with a simple configuration. The purpose is to obtain.

  An array antenna apparatus according to the present invention is an array antenna apparatus that includes a plurality of element antennas arranged at equal intervals on a straight line, and is capable of tilting the main beam direction from the broadside direction by a desired angle. X is an integer of 3 or more), and the second to Xth element antennas in one unit are delayed by the phase of power supplied to the element antenna. An output phase delay line is connected, and the phase delay line has a phase difference of 2πY / X (Y is an integer of 1 or more and Y / X is a number other than an integral multiple of 1/2). Thus, the phase is delayed.

According to the array antenna apparatus according to the present invention, the phase delay line is connected to the second to Xth element antennas of the X element antennas (X is an integer of 3 or more) and one unit, and the phase The delay line delays the phase so that the phase difference between adjacent element antennas is 2πY / X (Y is an integer equal to or greater than 1 and Y / X is a number other than an integer multiple of 1/2).
As a result, the same phase delay line can be used periodically and repeatedly, the types of phase delay lines to be used can be reduced, and the main beam direction can be tilted with a simple configuration.

It is a block diagram which shows the array antenna apparatus which concerns on Embodiment 1 of this invention. It is another block diagram which shows the array antenna apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the array antenna apparatus which concerns on Embodiment 2 of this invention. It is a block diagram which shows the array antenna apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows a coplanar microstrip array antenna. It is a block diagram which shows a single layer structure waveguide slot array antenna. It is another block diagram which shows the array antenna apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows a general array antenna apparatus. It is a block diagram which shows the array antenna apparatus which carries out the beam tilt of the main beam direction using a phase delay line. It is another block diagram which shows the array antenna apparatus which carries out the beam tilt of the main beam direction using a phase delay line.

  Hereinafter, preferred embodiments of the array antenna apparatus of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a block diagram showing an array antenna apparatus according to Embodiment 1 of the present invention.
In FIG. 1, the array antenna apparatus includes eight element antennas 1a to 1h arranged on a straight line at equal intervals d. In addition, an axis along the arrangement direction of the element antennas 1a to 1h is an x axis, and a broad side direction (a direction perpendicular to the x axis) of the array antenna apparatus is a z axis. Here, the main beam direction of the array antenna apparatus is assumed to be tilted by a predetermined angle θ ₀ from the z-axis direction (broadside direction) to the x-axis direction.

The element antennas 1a to 1h are connected to a power feed line 2 that feeds power to the element antennas 1a to 1h.
In addition, a phase delay line 3 a that provides a phase difference ΔP is inserted between the element antennas 1 b and 1 f and the feed line 2. Further, a phase delay line 3b that provides a phase difference 2ΔP is inserted between the element antennas 1c and 1g and the feeder line 2, respectively. Further, a phase delay line 3c that provides a phase difference 3ΔP is inserted between the element antennas 1d and 1h and the feed line 2.

That is, each of the phase delay lines 3a to 3c includes four element antennas 1a to 1d and element antennas 1e to 1h as one unit, and the second to fourth element antennas among the element antennas in one unit. Are connected to each. The phase delay lines 3a to 3c are inserted immediately behind the element antennas 1a to 1h. The feed line 2 and the phase delay lines 3a to 3c constitute a feed circuit of the array antenna device.
Here, the phase delay lines 3a to 3c give a phase difference ΔP (2ΔP, 3ΔP) so as to satisfy the following expression (2).

    ΔP = 2π / N (2)

In Equation (2), N is the number of element antennas in the unit, and N = 4 in the array antenna apparatus of FIG.
At this time, the phase delay line 3a gives a phase difference of π / 2, the phase delay line 3b gives a phase difference of π, and the phase delay line 3c gives a phase difference of 3π / 2. Therefore, the phase difference ΔP given between the adjacent element antennas 1a to 1h is π / 2, and the main beam direction can be tilted.
Moreover, it turns out that the phase difference for 1 period has generate | occur | produced from the element antenna 1a to the element antenna 1e. Thereby, the same phase delay lines 3a to 3c can be used periodically and repeatedly.

In the above formula (2), when N = 1, all the element antennas 1a to 1h are excited in the same phase, and when N = 2, the adjacent element antennas 1a to 1h are reversed. Excited with phase (0 and π). For this reason, since both cannot be tilted in the main beam direction, N is set to an integer of 3 or more.
Further, the total number of element antennas and the number N of element antennas in one unit are not limited to 8 and 4, respectively, and the total number of element antennas is larger than the number N of element antennas in one unit, If the number N of element antennas is an integer of 3 or more, another value may be used.

Here, the beam tilt angle θ ₀ in the main beam direction is expressed by the following equation (3) from the above equations (1) and (2). In equation (3), λ represents the wavelength of the frequency at which the array antenna apparatus is operated.

θ ₀ = sin ⁻¹ (λ / (N × d)) (3)

From Equation (3), in addition to the selection of the number N of element antennas in one unit, a desired beam tilt angle θ ₀ can be realized by adjusting the distance d between adjacent element antennas.

As described above, according to the first embodiment, the phase delay line is connected to the second to N-th element antennas among the N element antennas (N is an integer of 3 or more). The phase delay line delays the phase so that the phase difference between the adjacent element antennas is 2π / N.
As a result, the same phase delay line can be used periodically and repeatedly, the types of phase delay lines to be used can be reduced, and the main beam direction can be tilted with a simple configuration.
In addition, since the feeding circuit composed of the phase delay line and the feeding line is formed on the opposite side of the main beam direction with respect to the surface on which the plurality of element antennas are arranged, an array antenna device having a small plane area can be obtained. Can do. Therefore, even when the flat area of the attachment location is small, the attachment can be easily performed.

In the first embodiment, the power distribution configuration of the feeder line 2 is connected in parallel. However, the configuration is not limited to this, and may be formed in a tournament shape (multistage) as shown in FIG.
Here, when the power distribution configuration of the feed line 2 is connected in parallel, the number of stages of the feed line 2 and the line length can be reduced, so that the loss of the feed line 2 is reduced and the gain of the array antenna device is lowered. Can be prevented.

On the other hand, when the power distribution configuration of the feeder line 2 is a tournament, the power distribution ratio supplied to the element antennas 1a to 1h can be all made equal without any special design, thus simplifying the design procedure. Can be
Also, the power feed line may be configured by combining a parallel-connected power distribution configuration and a tournament-shaped power distribution configuration.

  In the first embodiment, in the above formula (2), N is an integer of 3 or more, but is not limited to this. The phase delay line may give a phase difference ΔP so as to satisfy the following expression (4) between adjacent element antennas. In Equation (4), K is an integer greater than or equal to 1, and L is an integer greater than or equal to 2K + 1 and smaller than the total number of element antennas.

    ΔP = 2πK / L (4)

Hereinafter, the case where K = 2 and L = 5 will be described in detail.
At this time, the phase differences (ΔP, 2ΔP,...) Given by the phase delay line are 4π / 5, 8π / 5, 12π / 5 (= 2π / 5), 16π / 5 (= 6π / 5), 20π / 5 (= 0), 24π / 5 (= 4π / 5), 28π / 5 (= 8π / 5)... From this result, it can be seen that the same phase difference is periodically repeated with five phase delay lines as one unit.
Therefore, in this case, the number of choices of the phase difference ΔP given by the phase delay device increases, so that the degree of design freedom can be increased.

  In addition to the above-described elements, a phase delay line is connected to the second to Xth element antennas among X (X is an integer of 3 or more) one unit element antenna, The phase delay line delays the phase so that the phase difference is 2πY / X (Y is an integer equal to or greater than 1 and Y / X is a number other than an integer multiple of 1/2), so that the same phase delay line Can be used periodically and repeatedly, the number of types of phase delay lines to be used can be reduced, and the main beam direction can be tilted with a simple configuration.

Embodiment 2. FIG.
In the first embodiment, the plurality of element antennas are arranged one-dimensionally on a straight line. However, the element antennas may be arranged two-dimensionally on a plane.
FIG. 3 is a block diagram showing an array antenna apparatus according to Embodiment 2 of the present invention. Note that the description of the same configuration as that of the first embodiment described above is omitted.
In FIG. 3, a direction orthogonal to the above-described x-axis and z-axis is defined as a y-axis.

  In FIG. 3, the array antenna apparatus includes subarrays 4a to 4h formed by arranging four element antennas 1a to 1h in the y-axis direction. The subarrays 4a to 4h are connected to a feed line 2 that feeds power to the subarrays 4a to 4h. In addition, a phase delay line 3a, a phase delay line 3b, and a phase delay line 3c are inserted between the subarrays 4a and 4f, the subarrays 4c and 4g, the subarrays 4d and 4h, and the feed line 2, respectively.

  As described above, according to the second embodiment, the two-dimensional array is formed by arranging the element antennas in the direction orthogonal to the arrangement direction of the plurality of element antennas and the broadside direction and forming the subarray. Thus, an array antenna apparatus having an arbitrary opening diameter can be obtained.

In the second embodiment, the power distribution configuration of the feeder lines in the subarrays 4a to 4h is formed in a tournament shape (multistage), but is not limited to this, and may be connected in parallel.
In this case as well, as described above, when the power distribution configuration of the feed line is connected in parallel, a decrease in the gain of the array antenna device can be prevented, and the power distribution configuration of the feed line is formed in a tournament shape. In this case, the design procedure can be simplified.
Also, the power feed line may be configured by combining a parallel-connected power distribution configuration and a tournament-shaped power distribution configuration.

In the second embodiment, power of the same phase is supplied to each of the element antennas 1a to 1h in each of the subarrays 4a to 4h. However, the present invention is not limited to this. The main antenna direction of the array antenna apparatus may be tilted from the z-axis direction to the y-axis direction by inserting phase delay lines in the sub-arrays 4a to 4h.
In this case, the main beam direction of the array antenna apparatus can be tilted in a two-dimensional direction.

Embodiment 3 FIG.
In the first and second embodiments, the power feeding circuit including the power feeding line 2 and the phase delay lines 3a to 3c is formed immediately behind the element antennas 1a to 1h (in the z-axis negative side direction). The element antennas 1a to 1h and the subarrays 4a to 4h may be formed on the xy plane.

FIG. 4 is a block diagram showing an array antenna apparatus according to Embodiment 3 of the present invention. The description of the same configuration as in the first and second embodiments is omitted.
In FIG. 4, a feeding circuit composed of the feeding line 2 and the phase delay lines 3 a to 3 c is on the xy plane where the element antennas 1 a to 1 h and the subarrays 4 a to 4 h are formed, and the arrangement direction of the element antennas 1 a to 1 h ( It is formed so as to extend in a direction orthogonal to the (x-axis direction) (y-axis direction).

A specific example of such an array antenna device is a coplanar microstrip array antenna shown in FIG.
In FIG. 5, the coplanar microstrip array antenna includes a microstrip antenna 5, a microstrip feed line 6, and different types of phase delay lines 7a to 7c.
Here, the phase delay lines 7 a to 7 c are realized by meandering a part of the microstrip feed line 6.

Another specific example of such an array antenna apparatus is a single-layer waveguide slot array antenna shown in FIG.
In FIG. 6, the single-layer waveguide slot array antenna is formed by a waveguide 8. A radiation slot 9 is provided on the wide wall surface of the waveguide 8. Different types of phase delay lines 10 a to 10 c are realized by changing a part of the width of the wide surface of the waveguide 8.

  As described above, according to the third embodiment, the feeding circuit including the phase delay line and the feeding line is on the same plane as the plane on which the plurality of element antennas are arranged, and is arranged in the arrangement direction of the plurality of element antennas. Since it is formed in a direction orthogonal to the array antenna device, a low-profile array antenna device can be obtained.

  In the third embodiment (FIGS. 4 to 6), all the power feeding circuits are formed only on one side when viewed from the element antennas 1a to 1h. However, the present invention is not limited to this. As shown in FIG. 7, in the power feeding circuit, a part of the power feeding line is formed on one side of the element antennas 1 a to 1 h (in the negative y-axis direction), and the remaining part of the power feeding circuit is the other side of the element antennas 1 a to 1 h. The feeding circuit may be disposed so as to sandwich the element antennas 1a to 1h.

For example, when a three-dimensional structure such as a waveguide is used as a power feeding circuit, it is difficult to densely arrange the power feeding line and the phase delay line only on one side of the element antenna. May get worse.
In such a case, the power feeding circuit can be easily mounted by disassembling and arranging the power feeding circuit on both sides of the element antenna.
In FIG. 7, the power feeding port to the power feeding circuit is divided into two locations. However, by providing a circuit that multiplexes the antenna and synthesizes two power feeding ports on the back surface of the antenna, Power can be supplied to the power feeding circuit.

  1a to 1h Element antenna, 2 Feed line, 3a to 3c Phase delay line, 4a to 4h Subarray.

Claims (8)

An array antenna apparatus comprising a plurality of element antennas arranged at equal intervals on a straight line, and capable of tilting a main beam direction by a desired angle from a broadside direction,
With X element antennas (X being an integer of 3 or more) as a unit, the second to X of the element antennas in one unit have the phase of power supplied to the element antennas. A phase delay line that outputs with delay is connected,
The phase delay line delays a phase so that a phase difference between adjacent element antennas is 2πY / X (Y is an integer of 1 or more, and Y / X is a number other than an integer multiple of 1/2). An array antenna device. The array antenna apparatus according to claim 1,
X is an integer greater than or equal to 2Y + 1.   3. The array antenna apparatus according to claim 1, wherein element antennas are arranged in a direction perpendicular to the arrangement direction of the plurality of element antennas and the broadside direction to form a subarray.   A feeding circuit comprising a feeding line for supplying power to the phase delay line and the plurality of element antennas is formed on a side opposite to the main beam direction with respect to a surface on which the plurality of element antennas are arranged; The array antenna apparatus according to claim 1, wherein the array antenna apparatus is characterized in that:   A feeding circuit comprising a feeding line for supplying power to the phase delay line and the plurality of element antennas is on the same plane as the plane on which the plurality of element antennas are arranged, and is arranged in the arrangement direction of the plurality of element antennas. 4. The array antenna device according to claim 1, wherein the array antenna device is formed in a direction orthogonal to the array antenna.   A part of the feeding circuit is formed on one side in a direction orthogonal to the arrangement direction of the plurality of element antennas, and the remaining part of the feeding circuit is orthogonal to the arrangement direction of the plurality of element antennas. The array antenna apparatus according to claim 5, wherein the array antenna apparatus is formed on the other side in the direction in which the signal is transmitted.   The array antenna device according to any one of claims 4 to 6, wherein the feed line connects the element antenna or the phase delay line in parallel.   The array antenna device according to any one of claims 4 to 6, wherein the feed line is branched in multiple stages to connect the element antenna or the phase delay line.

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