JPH1141024A - Antenna feeding section - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antenna feeding section in which the number of phase shifters inside a phase shifting device is reduced so as to reduce its size as well as its cost. SOLUTION: The proposed antenna feeding section 5 is provided with a phase shifting device 6 that supplies N-sets of exciting power with different phases to an array antenna to very a tilting angle of a radiation beam, receives an input exciting power and outputs M1 (M1=N/2 and N is an even number) or M2 (M2=(N-1)/2 and N is an odd number) sets of exciting power with different phases respectively; branching means 101 -103 that branch M1 or M2 sets of exciting power with different phases into two respectively; and phase adjustment means 81 -86 that adjust phases of N-sets of exciting power outputted from the branch means or (N-1)-sets of exciting power outputted from the branch means and the input exciting power so as to supply the resulting power to the array antenna.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna feed section, and more particularly to a technique which is effective when applied to a technique for reducing the size of a phase shift device in an antenna feed section.

[0002]

2. Description of the Related Art In a mobile communication method represented by a cellular phone, a wide service area is divided into small zones so that limited frequencies can be effectively used, that is, the number of base stations is increased and each base station is increased. Narrow the service area of the station,
The frequency is used repeatedly.

When the service area of a base station is narrowed, the radiation beam of the base station antenna is used by tilting it slightly downward, that is, by "tilting", the radiation beam jumps too much and interferes with other zones. Not to give.

As means for tilting the radiation beam of the base station antenna downward without tilting the antenna itself diagonally downward, so-called tilting means, in a conventional base station antenna, antenna elements are vertically arranged in multiple stages. In addition, a feeder cable is connected to each antenna block in which a plurality of antenna elements are collectively formed as appropriate, and the phase of the excitation power fed to each antenna block is shifted from the uppermost antenna block. The maximum gain direction of the array antenna is inclined obliquely downward from the horizontal plane as appropriate, so as to be sequentially delayed over the lowermost antenna block.

[0005]

There is a case where the tilt angle of the array antenna of the base station needs to be changed in accordance with increase or decrease of traffic or new establishment of the base station. Therefore, the antenna feed unit changes the phase amount of the excitation power fed to each antenna block to change the tilt angle of the radiation beam of the array antenna of the base station.

Conventionally, as such an antenna feeding section, an antenna feeding section that changes the length of each feeding cable connected to each antenna block has been used. In order to change the length of the power supply cable, it is necessary to remove the power supply cable from the connector and replace it with a power supply cable of a different length, and there is a problem that an extremely labor- and time-consuming operation is required. .

In order to solve the above problem, a phase shifter having the same number of phase shifters as the number of antenna blocks is provided inside the antenna feeder, and each antenna block is fed by the phase shifter in the phase shifter. 2. Description of the Related Art There is known an antenna feed unit that varies a tilt angle of a radiation beam of a base station antenna by varying a phase amount of excitation power to be performed for each antenna block.

[0008] However, in this antenna feeding section,
The same number of phase shifters as the number of the antenna blocks are required inside the phase shifter, which causes a problem that the antenna feeder becomes large and the cost is high.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to reduce the number of phase shifters provided inside a phase shifter in an antenna feed section. Another object of the present invention is to provide a technology that enables the size and cost of the apparatus itself to be reduced.

The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

[0011]

SUMMARY OF THE INVENTION Among the inventions disclosed in the present application, the outline of a representative one will be briefly described.
It is as follows.

[0012] In the antenna feed section of the tilt angle variable array antenna which feeds N excitation powers having different phases to the array antenna and varies the tilt angle of the radiation beam, M1 having different phases from the input excitation power.
(M1 = N / 2: N is an even number) or M2 (M2
= (N−1) / 2: N is an odd number) excitation powers, and M1 or M2 excitation powers of different phases, output from the phase shifter, are output by two. Branching means for branching, and N excitation powers output from the branching means, or output from the branching means (N
-1) phase adjusting means for adjusting the respective phases of the excitation power and the input excitation power to supply power to the antenna block.

That is, in the present invention, since the phase shifter having one input and M1 (or M2) output is used as the phase shifter, the size and cost of the device itself can be reduced. .

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings.

In all the drawings for describing the embodiments, those having the same functions are denoted by the same reference numerals, and their repeated description will be omitted.

FIG. 1 is a block diagram showing a schematic configuration of a tilt angle variable array antenna to which an antenna feed unit according to an embodiment of the present invention is applied.

[0017] In the figure, reference numeral 1 denotes an antenna cover, 2 ₁
~ 2 ₆ antenna blocks, each consisting of a plurality of antenna elements, 3 ₁ to 3 ₂₄ antenna elements, ₄₁ to ₆ equal length feeding cable, 5 antenna feed, 6 1 Input 3 Output 7 _{1 to} 7 ₃ are phase shifters, and 8 ₁ to 8 ₆
Denotes a second phase adjustment cable, 9 denotes a device side terminal, and 10 ₁ to
10 ₃ 2 splitter, 11 ₁ to 11 ₃ are, first phase adjustment cable.

In FIG. 1, the high-frequency excitation power input from the device-side terminal 9 is supplied to a phase shifter (7 ₁ to 7 ₁ ) in the phase shift device 6.
7 ₃ ) and the first phase adjustment cable (11 _{1 to} 11 ₃ )
After being divided into predetermined amplitude and phase values, then divided into two by two branching devices (10 ₁ to 10 ₃ ), and further subjected to phase adjustment by a second phase adjusting cable (8 ₁ to 8 ₆ ). , Are sent to each antenna block (2 ₁ to 2 ₆ ) in the antenna cover 1 and are further distributed in each block to receive the antenna element (3
Reaches the _{1-3 24),} is emitted.

The excitation amplitude and phase of the antenna element (3 ₁ to 3 _24), phase shifter phase shifting device 6 (7 ₁ to 7 ₃₎ and a first phase adjustment cable (11 ₁ to 11 _3), second phase adjusting cable (8 _{1-8 6),} as well as determined by the synergistic value of the phase characteristics of each antenna block (2 ₁ to 2 _6), have been in the desired radiation characteristics as a whole can be obtained.

[0020] In the array antenna antenna feed of this embodiment is applied, in varying the tilt angle, and controls the phase shifting device 6, are output from the phase shifter (7 ₁ to 7 ₃₎ Variable output phase amount. Thus, varying the tilt angle of the radiation beam emitted from each antenna element of the array antenna (3 ₁ to 3 _24).

This situation will be described with reference to FIGS.
2 (b) is in the array antenna antenna feed of this embodiment is applied, when the reference tilt angle at the time of design, the phase shifter (7 ₁ to 7 _3), the first phase adjustment cable (11 _{1 to} 11 ₃ ), the second phase adjustment cable (8 ₁ to
8 _6), and each antenna element of the antenna blocks (2 ₁ to 2 ₆₎ in (3 ₁ to 3 ₂₄₎ the phase of each represent (delay amount), 3 (b) is, phase shifting device 6 controlled to the case of variable tilt angle, the phase shifter (7 ₁ to 7 _3), the first phase adjustment cable (11 ₁ to 11 _3), the second phase adjustment cable (8 _{1-8 6)} , and antenna block (2 ₁ to 2 ₆₎
An example of the phase of each antenna element (3 ₁ to 3 ₂₄₎ for each of the inner (delay amount) represents respectively.

In FIG. 2B and FIG. 3B, 22a
The first phase adjustment cable (11 ₁ to 11 _3), 22b and the second phase adjustment cable (8 _{1-8 6),} 23 ₁ phase shifter (7 ₁ to 7 _3), 24 denotes an antenna block ( each antenna element 2 ₁ to 2 ₆₎ in (3 ₁ to 3 _{2 4)} phase of each (delay amount)
Is shown. Also, FIG. 2 (a), FIG. 3 (a), referenced to the phase of the excitation power fed to the antenna element 3 _1, the excitation power of the phase fed to each antenna element (3 _{2-3 24)} represents (delay amounts), each antenna element (3 _{two or} three
₂₄ ) shows the excitation phase characteristics of the radiation beam emitted from. In each figure, the element number represents an antenna element, and the element number 1 is the top antenna element 3
_The element number ₂₄ indicates the antenna element 324 at the lowest stage.

[0023] FIG. 2 (b), the as shown in FIG. 3 (b), the phase amount 24 of each antenna element (3 ₁ to 3 ₂₄₎ in each antenna block (2 ₁ to 2 ₆₎ is a fixed value Is done. Also,
Phase amount 22a of the phase shifter (7 ₁ to 7 ₃₎ of the phase amount 23 ₁ and the first phase adjustment cable (11 ₁ to 11 ₃₎ comprises an antenna block 2 ₅ and the antenna block 2 _6, the antenna block 2 ₃ It is the same with the antenna block 2 _4, and an antenna block 2 ₁ and the antenna block 2 _2. However, by adjusting the length of each phase adjusting cable (8 _{1-8 6)} adjusts the phase amount 22b of each phase adjusting cable (8 _{1-8 6),} as shown in FIG. 2 (b) If the reference tilt angle at the time of design, the phase of the excitation power fed to each antenna element (3 ₁ to 3 _24), the top of the antenna element 3
₁ from over the bottom of the antenna element 3 _24, so as to be successively delayed.

In this case, each antenna element (3 ₁ to 3 ₁ )
3 phases of the radiation beam emitted from the ₂₄₎ (wave), the 2 (as shown in a), based on the radio wave phase radiated from the antenna element 3 in ₁ uppermost, lowermost antenna elements 3 Delayed sequentially over ₂₄ . Thus, the excitation phase characteristics of the radiation beam emitted from each antenna element (3 ₁ to 3 _24), i.e., the excitation phase characteristics across the array antenna, as 25 ₁ shown in FIG. 2 (a), a clean straight line And good tilt characteristics can be obtained.

On the other hand, in the case of the example shown in FIG. 3 (b) that varies the tilt angle by controlling the phase shifting device 6, a phase quantity 23 ₁ of the phase shifting device 6 is changed, thereby, the whole array antenna FIG. 3A shows that the excitation phase characteristic changes in a direction in which the tilt angle becomes shallower.

[0026] In the present embodiment, in place of the phase adjustment cable (8 _{1-8 6),} it is also possible to use a microstrip line.

FIG. 4 is a block diagram showing a schematic configuration of a tilt angle variable array antenna to which a conventional antenna feed unit is applied.

The antenna feeding portion 5 shown in the figure, inside the 7 ₁ to 7 ₆ 6 phase shifter is provided, first input 6
An output phase shifter 6 is provided, and a 2-branch (10 ₁ to 1)
0 ₃ ) is omitted.

In FIG. 4, the high-frequency excitation power input from the device-side terminal 9 is distributed to predetermined amplitude and phase values by the phase shift device 6, and further, the phase adjustment cables (8 ₁ to 8 ₁ ) are provided.
After being phase-adjusted by 8 _6), it is sent to each antenna block in the antenna cover 1 (2 ₁ to 2 _6), leading to further distributed to the antenna elements (3 ₁ to 3 ₂₄₎ in each block,
Radiated.

[0030] Also in the conventional array antenna antenna feed is applied to a variable tilt angle, and controls the phase shifting device 6, for varying the output phase quantity from the phase shifter (7 ₁ to 7 ₆₎ .

This situation will be described with reference to FIGS.
FIG. 5B shows an array antenna to which a conventional antenna feed unit is applied, in the case of a reference tilt angle at the time of design.
Phase shifter (7 ₁ to 7 _6), the phase adjustment cable (8 _{1-8 6),}
And each antenna element of the antenna blocks (2 ₁ to 2 ₆₎ in (3 ₁ to 3 ₂₄₎ the phase of each represent (delay), also,
6 (b) is, in the case of changing the tilt angle by controlling the phase shifting device 6, the phase shifter (7 ₁ to 7 _6), the phase adjustment cable (8
It represents _{1-8 6),} and each antenna element of the antenna blocks (2 ₁ to 2 ₆₎ in (3 ₁ to 3 ₂₄₎ the phase of each of an example of a (delay amount), respectively.

[0032] FIG. 5 (b), in FIG. 6 (b), 22 is a phase adjustment cable (8 _{1-8 6),} 23 ₁ phase shifter (7 ₁
7 _6), 24 denotes an antenna block (2 ₁ to 2 ₆₎ phase of each antenna element (3 ₁ to 3 ₂₄₎ each in the (delay amount). Further, FIG. 5 (a), and FIG. 6 (a) shows the excitation phase characteristics of the radiation beam emitted from each antenna element (3 _{2-3 24).}

[0033] In the conventional array antenna antenna feed is applied, the amount of phase 23 ₁ of the phase shifter (7 ₁ to 7 _6),
Adjusts the phase amount 22 of each phase adjusting cable (8 _{1-8 6),} as shown in FIG. 5 (b), when the reference tilt angle at the time of design, the feed to each antenna element (3 ₁ to 3 ₂₄₎ It is the excitation power of the phase, over the bottom of the antenna element 3 ₂₄ from the antenna element 3 in ₁ uppermost, so that is sequentially delayed.

Therefore, even in the case of the array antenna to which the conventional antenna feed section is applied, the excitation phase characteristic of the entire array antenna is not as shown in FIG.
As in the 25 ₁ (a), the has become a clean straight line may tilt characteristics.

On the other hand, in the example shown in FIG. 6B in which the tilt angle is varied by controlling the phase shifter 6, the phase shifters (7 ₁ to 7 ₁ ) are used.
The phase amount 23 ₁ of 7 ₆ ) changes, and as a result, as shown in FIG. 6A, the excitation phase characteristic of the entire array antenna changes in the direction of decreasing the tilt angle. ing.

As is clear from FIGS. 3A and 6A, even if the tilt angle of the radiation beam radiated from the array antenna is varied by the antenna feed unit 5 of the present embodiment, total excitation phase characteristics 25 ₂ at is substantially linear, gain and side lobe characteristics can be obtained so without degradation, equivalent to the conventional antenna feed the gain and sidelobe characteristics.

However, in the present embodiment, the phase shifter inside the phase shifter 6 is only half as compared with the conventional example, and not only can the size of the antenna feeder 5 be reduced by that much, but also Costs can be reduced.

FIGS. 7 to 9 are views showing an example of a phase shifter applicable to the antenna feed unit 5 of the present embodiment.
FIG. 7 is a side view, FIG. 8 is an exploded perspective view seen from obliquely right front,
FIG. 9 is an exploded perspective view as viewed obliquely from the front left.

7 to 9, on the outer surface of a rotating dielectric substrate (hereinafter simply referred to as a rotating substrate) 31, an inner end is located at the center of the rotating substrate 31, and an outer end extends in a radial direction. An input line 32 having an appropriate length, an impedance matching line 33 and an input coupling line 34 provided as needed are provided. In the center of the rotating substrate 31, a through hole 36 is provided.
Is formed, and the tip of the inner conductor 52 of the knob 51 is inserted into the inner diameter of the knob 51 firmly or with appropriate hardness.

A ground conductor 35 made of copper or the like is provided on the inner surface of the rotating substrate 31 over the entire inner surface. A portion of the ground conductor 35 corresponding to the input coupling line 34 provided on the outer surface of the rotating board 31 is:
The ground conductor is removed to form the input coupling slot 37.

The input line 3 provided on the outer surface of the rotating substrate 31
2. A strip line is formed by the dielectric material of the rotating substrate 31 and the ground conductor 35 provided on the inner surface of the rotating substrate 31, and the input coupling line 3 provided on the outer surface of the rotating substrate 31
4 and the input coupling slot 37 provided on the inner surface form an input-side excitation circuit.

A thin dielectric plate (hereinafter simply referred to as a thin plate) 3
The plate surface 8 has the same structure as the plate surface facing the rotating substrate 31 and the rear surface thereof, and a through hole 39 through which the external conductor 53 of the knob 51 is inserted is provided at the center.

A fixed dielectric substrate (hereinafter simply referred to as a fixed substrate) 40 is provided with a through hole 41 through which an outer conductor 53 of a knob 51 is inserted. An arc-shaped output coupling line 42 is provided. On the inner surface of the fixed substrate 40, a ground conductor 45 made of copper or the like is provided over the entire inner surface. The portion of the ground conductor 45 corresponding to the output coupling line 42 provided on the outer surface thereof is removed from the ground conductor to form an output coupling window 46.

The output coupling line 42 provided on the outer surface of the fixed substrate 40, the output coupling window 46 provided on the inner surface and the thin plate 3
An output-side excitation circuit is formed by a strip line composed of the ground conductor 35 on the inner surface of the rotating substrate 31 opposed to the output substrate 8 through the output line 8. A strip line is formed by the output lines (43, 44) provided on the outer surface of the fixed substrate 40, the dielectric material of the fixed substrate 40, and the ground conductor 45 provided on the inner surface.

The inner conductor 55 of the input terminal 54 and the knob 51
The internal conductors 52 are aligned with each other and the internal conductors 55 are relatively rotatable around the axis, and are electrically connected to each other via a capacitor. On the other hand, the outer conductor 56 of the input terminal 54 and the outer conductor 53 of the knob 51 also have their axes aligned with each other, and the outer conductor 56 is relatively rotatable around this axis. Connected.
That is, the knob 51 and the input terminal 54 form a rotary joint.

In the phase shifters shown in FIGS. 7 to 9, the high-frequency excitation power applied to the input terminal 54
1 is applied to the input line 32 and the ground conductor 35 of the rotating board 31 via the inner conductor 52 and the outer conductor 53 of the rotating board 31, and the input coupling line 34 and the input coupling line 34 are provided via the impedance matching circuit 33 provided if necessary. The input-side excitation circuit including the input coupling slot 37 is excited.

The electromagnetic wave generated from the input-side excitation circuit is output-excited by the ground conductor 35 of the rotating board 31 and the output-coupling line 42 of the fixed board 40 which are opposed to each other through the thin plate 38 and the output-coupling window 46 of the fixed board 40. Excite the circuit.

The high-frequency power generated in the output coupling line 42 by this excitation is distributed right and left with the excitation point as a boundary, transmitted through the output coupling line 42 in opposite directions, and provided with an impedance matching line ( 49, 50) and output lines (43, 44), output terminals (47, 50).
48).

When the length of the line from the excitation point to the terminal 47 is equal to the length of the line from the excitation point to the terminal 48, the phase amount of the power from the excitation point to the terminal 47 and the amount of the power from the excitation point to the terminal 48 are determined. And the amount of power phase is equal to each other.
7, 48) have opposite phases and the same amplitude.

When the rotary substrate 31 is rotated by operating the knob 51, the excitation point of the output coupling line moves in the circumferential direction in accordance with the rotation angle, and the line from the excitation point to the output terminal 47 changes. The length and the length of the line reaching the output terminal 48 are different from each other, and the phase amount of the power output from the terminal connected to the line on the side where the length from the excitation point has become shorter becomes smaller. The phase amount of the electric power output from the terminal connected to the line on the side where the length from the point becomes longer becomes large.

By using the phase shifter shown in FIGS. 7 to 9 for the antenna feed unit 5 of the present embodiment, it is possible to remotely control the tilt angle of the array antenna.

The phase shifter is provided by the same applicant.
This phase shifter is described in Japanese Patent Application No. 8-163304 already filed, and other phase shifters include:
For example, it is already described in Japanese Patent Application No. 8-163304,
It goes without saying that phase shifters other than those shown in FIGS. 7 to 9 can be used.

As described above, the invention made by the present inventor is:
Although the present invention has been described in detail with reference to the embodiment, the present invention is not limited to the embodiment, and it is needless to say that various changes can be made without departing from the scope of the invention.

[0054]

The effects obtained by typical ones of the inventions disclosed in the present application will be briefly described as follows.

(1) According to the present invention, in the antenna feed unit applied to the tilt angle variable array antenna, the number of phase shifters provided inside the phase shift device is reduced, and the device itself is reduced in size and cost is reduced. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a tilt angle variable array antenna to which an antenna feed unit according to an embodiment of the present invention is applied;

FIG. 2 is a diagram showing a phase amount of excitation power for each antenna element in a case of a reference tilt angle at the time of design in an array antenna to which the antenna feed unit of the present embodiment is applied.

FIG. 3 is a diagram showing a phase amount of excitation power for each antenna element when a tilt angle is varied in an array antenna to which the antenna feed unit of the present embodiment is applied.

FIG. 4 is a block diagram illustrating a schematic configuration of a tilt angle variable array antenna to which a conventional antenna feed unit is applied.

FIG. 5 is a diagram showing a phase amount of excitation power for each antenna element in a case of a reference tilt angle at the time of design in an array antenna to which a conventional antenna feed unit is applied.

FIG. 6 is a diagram showing a phase amount of excitation power for each antenna element when a tilt angle is varied in an array antenna to which a conventional antenna feed unit is applied.

FIG. 7 is a side view of an example of a phase shifter applicable to the antenna feed unit according to the present embodiment.

FIG. 8 is an exploded perspective view of an example of a phase shifter applicable to the antenna feed unit according to the present embodiment, as viewed from obliquely right front.

FIG. 9 is an exploded perspective view of an example of a phase shifter applicable to the antenna feed unit according to the present embodiment, as viewed obliquely from the front left.

[Explanation of symbols]

1 ... antenna cover, 2 ₁ to 2 ₆ ... plurality of antenna elements antenna block consisting of, 3 ₁ to 3 ₂₄ ... antenna element, ₄₁ to ₆ ... power supply cable, 5 ... antenna feed, 6
… 1 input 3 output phase shifter, 7 _{1 to} 7 ₆ … Phase shifter, 8 ₁ to
8 ₆ … second phase adjustment cable, 9… device side terminal, 10 ₁
... _{3 to} 2 splitters, 11 _{1 to} 11 ₃ ... First phase adjustment cable, 31. rotating dielectric substrate, 32.
3, 49, 50 ... impedance matching line, 34 ... input coupling line, 35, 45 ... ground conductor, 36, 39, 41 ...
Through-hole, 37: input coupling slot, 38: dielectric thin plate,
40: fixed dielectric substrate, 42: output coupling line, 43, 4
4 output line, 46 output coupling window, 47, 48 output terminal, 51 knob, 52, 55 internal conductor, 53, 56
... external conductor, 54 ... input terminal.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaka Shintaku 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communication Network Co., Ltd. (72) Inventor Masaharu Karikome No. 1 Iwamotocho Building Nippon Dengyo Co., Ltd.

Claims (1)

[Claims] 1. An antenna feeding section of a tilt angle variable array antenna for feeding N excitation powers having different phases to an array antenna and varying a tilt angle of a radiation beam, wherein M1 having a different phase from an input excitation power. (M1 =
N / 2: N is an even number, or M2 (M2 = (N−
1) / 2: N is an odd number) of phase shifters for outputting excitation power, and M having different phases output from the phase shifter.
Branch means for branching one or M2 excitation powers into two; N excitation powers output from the branching means, or (N-1) excitation powers output from the branching means; An antenna feeding unit comprising: a phase adjusting unit that adjusts each phase of the input excitation power and feeds the power to the array antenna.