JP3365406B2 - Antenna device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antenna device configured to supply power to a plurality of antenna elements from a feeding point. In particular, the present invention relates to a planar antenna having a structure in which a large number of microstrip array antennas are formed and electric power is supplied by microstrip lines. The present invention is particularly effective for a small planar antenna as a radar transmitting and receiving antenna mounted on, for example, an automobile.

[0002]

2. Description of the Related Art Conventionally, USP4063245 is known as a planar array antenna using a microstrip conductor. As shown in FIG. 8, the antennas are arranged in rows on a dielectric substrate 91 having a ground conductor layer 92 formed on one surface thereof, extending linearly in parallel and having one end connected and the other end open. The first feeding path 93 formed of the formed microstrip line is formed. A plurality of antenna elements 94a to 94e protruding laterally from the first feeding path 93 are connected to each first feeding path 93 to form a linear array. The first feeding line 93 of each linear array is the second feeding line 9
5 and the combined signal is connected to the center 9 of the second feeding line 95.
6 outputs a two-dimensional array antenna.

The antenna elements 94a to 94e are arranged at intervals of the wavelength λ _g of the radio wave propagating through the first feeding path 93 at the operating frequency, and their length (distance from the connection point to the open end) is about λ _g . It is set to half or λ _g / 2.
Further, since the antenna elements 94a to 94e can control the excitation amplitude of each element by changing the width thereof, the directional characteristics required for the antenna, that is, the gain or the side lobe level, etc. are set to the purpose (specification). It can be adapted. For example, in this figure, the antenna element 94a,
The element at the both ends of 94e and the like has a narrower width, the excitation amplitude is made smaller, the element near the center such as the antenna element 94c is made wider, and the antenna element 94e is opened and terminated 97.
It is possible to realize standing wave excitation by arranging from the position of λ _g to λ _g , and to make the overall amplitude distribution in each linear array into a mountain shape that becomes larger near the center. With this amplitude distribution, low sidelobe characteristics can be realized.

[0004]

If the number of the first power feeding paths as shown in FIG. 8 is large and the number of the first power feeding paths to which the radiating element is connected is large, the power feeding point or the output point and each first The second power feeding path for connecting the power feeding paths of the above has a plurality of branches. Here, for example, JR James and PS Hall
"Handbook of microstrip antennas," Peter Peregrin
us Ltd., 1989 pp.841,842 has 2 from one feeding point S
An example is shown in which a large number of branches are used (Fig. 9 (a)) and in which one main line is sequentially branched (Fig. 9 (b)). 9A shows a configuration of four power feeding paths and FIG. 9B shows a configuration of second power feeding paths for connecting to eight first power feeding paths. For simplicity, the antenna element A _ij is shown by a white circle near its connection point.

When the two branches as shown in FIG. 9A are frequently used, it can be seen that a loss occurs in the power feeding path as shown in FIG. 9C. In the power feeding path from the feeding point 920 to the point 924, the “return” that should be originally avoided is generated in the right direction from the branch point 921 to the direction change point 922 and the left direction from the branch point 923 to the direction change point 924. On the other hand, FIG.
The one such as (b) that sequentially branches from one main line does not have such a loss, and it seems that an optimum route can be designed. However, for example, as shown in FIG. 10, when a second power feeding line for feeding equal power to the 16 first power feeding lines (input end points thereof, white circles in FIG. 10) from the power feeding point 930 at the center is formed, At points 931a and 931b, the power distribution ratio needs to be 7: 1.

As described above, when the number of the first feeding lines for feeding the antenna element is extremely large, the second feeding line having a large number of branch points causes a return as shown in FIG.
Only those having a large power distribution ratio as shown in FIG. 10 were known. In this specification, "a large power distribution ratio" means that the difference in the distributed power (the ratio of the large power side to the small power side) is large. These problems are as follows. Since the power loss of the microstrip line increases as the line length increases, the one that causes the return as shown in FIG. 9A is not preferable as the design of the power feeding path. Further, when the microstrip line in the millimeter wave band is formed on the dielectric substrate of several to several tens of centimeters square, the line width is naturally limited, and a branch point having a large power distribution ratio is formed as shown in FIG. It was technically difficult.

A further explanation is given for the limit of the power distribution ratio.
It It has a conductor ground plate on the back side and has a relative permittivity of 2.2 and a thickness of 0.127.
Form a microstrip line of width w on a mm dielectric substrate
Characteristic impedance Z when₀Is as shown in FIG.
It The microstrip line is used to transmit and receive millimeter-wave band radar.
Show conditions and impedance range with belief in mind
There is. Now, the characteristic impedance is 50Ω (that is, the characteristic impedance in FIG.
Power supply line L with a width of 0.39 mm) ₁Branch to₂, L₃To form the characteristic
Power supply line L with impedance 50 Ω_Four, L_FiveThinking to connect to
It For example, the power distribution ratio at the branch is L₂L_FourSide: L₃L_FiveOn the side 4:
1 (FIG. 12). Easy for impedance matching
From a simple calculation, branch L₂, L₃The characteristic impedance at is that
Calculated as 56Ω and 112Ω respectively, and the line width w corresponding to them
Are calculated as 0.33 mm and 0.08 mm from FIG. 11, respectively.
However, the dielectric substrate of several to several tens of centimeters square is etched.
The width of the microstrip line formed by
0.1mm is the limit for reliable products.
ing. This is the power distribution ratio in this simulation.
It is impossible to branch more than 4: 1, such as 7: 1
Means there is. Regarding the limit of the power distribution ratio at the branch
Change significantly even if the simulation conditions are changed.
Not bad.

The present invention has been made to solve the above problems, and an object thereof is to provide a large number of first power supply paths without "return" in the power supply path and without increasing the power distribution ratio in the branch. An object of the present invention is to provide an antenna device having a second power feeding path capable of feeding power to the power feeding path.

[0009]

In order to solve the above problems, according to the first aspect of the present invention, there is provided an array antenna comprising a plurality of antenna elements connected to a linear first feeding path. A plurality of power feeding lines are provided so as to be parallel to each other, and a branch point is provided to input power from each of the plurality of first power feeding lines from one power feeding point near the outer circumference of the device. In the antenna device having the second power feeding path formed as described above, the second power feeding path includes a power feeding point and an input end point of an arbitrary first power feeding path at each branch point and direction changing point. When the power feeding path segment is decomposed into the power feeding path segments, the power feeding path segments which are not parallel to the first power feeding path are frustrated and their orthogonal projections have the same direction, and the second power feeding path is an arbitrary power feeding path. Through 3 or more branch points Characterized in that it is intended to reach the input end point of the first feed line.

Here, the meanings of the terms and expressions in claim 1 will be clarified. The antenna device of the present application can also be applied to a transmitting antenna and a receiving antenna such as a radar. According to the reciprocity theorem, the characteristics of the transmitting antenna are equal to the characteristics when used for reception. In the present application, the term “transmission antenna” is only used for simplifying the expression of the claims, but it is obvious that the invention as a reception antenna is also included.

According to a second aspect of the present invention, a plurality of array antennas each having a plurality of antenna elements connected to a linear first feed line are arranged so that the first feed lines are parallel to each other. And a second power supply path formed with a branch point so as to supply power from one power supply point near the outer periphery of the device to the input end points of each of the plurality of first power supply paths. In the antenna device, the second power feeding path is a first power feeding path when the power feeding point and the input end point of the arbitrary first power feeding path are divided into power feeding path segments at branch points and direction changing points. The power supply path segments that are not parallel to the power supply path are vectors in which the orthogonal projections have the same direction, and the second power supply path has a power distribution ratio of 1.
A power feeding path that reaches the input end point of the first power feeding path through a branching point exceeding 5: 1 has two or more branching points such that one or more feeding paths exist at any of the branching destinations. Characterize. Here, the power distribution ratio exceeding 1.5: 1 means that when the smaller distributed power is 1, the larger distributed power value exceeds 1.5.

According to a third aspect of the invention, there are 16 or more array antennas. According to the means of claim 4, the power distribution ratio is 2.
It is characterized by having four or more branch points exceeding 5: 1. Here, the power distribution ratio exceeding 2.5: 1 means that the value of the larger distributed power exceeds 2.5 when the smaller distributed power is 1.

According to the means of claim 5, the conductor is arranged on the surface of the dielectric substrate having the ground conductor plate on the back surface, and the array antenna is a microstrip array antenna. The feeding point is arranged near the outer periphery of the surface of the dielectric substrate. Further, according to the means of claim 6, in the microstrip array antenna, the field emission edge lines are fed strip line at predetermined intervals along at least one first side of the both sides of the first feed path. The antenna elements are connected and arranged from the sides so as to form an angle of 45 degrees with respect to the length direction of the antenna, and the antenna element propagates through the first feed line at the operating frequency whose length is preset. Has a distribution of a width corresponding to the position of the excitation amplitude of each antenna element, which is an integer multiple of approximately 1/2 of the radio wave wavelength, and whose width is preset so as to provide a desired directional characteristic. Is the first
It is characterized in that it is composed of a strip conductor which is connected to the power feeding path of and has the other end opened.

According to a seventh aspect of the invention, the antenna element has a strip shape whose width is smaller than its length. According to the means of claim 8, the antenna element has a rectangular shape, and
It is characterized in that it is connected to the first power feeding path only near two vertex angles. Further, according to the means of claim 9, in the width distribution, the antenna element is connected to the first feeding path with the same width from the root portion in a region where the width of the antenna element is narrowed, and the width is shorter than the length. Is a small strip-shaped element,
In the region where the width of the antenna element is widened, the antenna element has a rectangular shape connected to the first feeding path only near the apex angle.

[0015]

[Operation and Effect of the Invention] When an arbitrary power feeding path is decomposed into power feeding path segments at branching points and direction changing points, power feeding path segments that are not parallel to the first power feeding path are jealous. A vector that does not have a "return" in the feeding direction. In addition, since an arbitrary power feeding path passes through three or more branch points from the power feeding point, even if the power distribution ratio at each branch point is small, the power at the power feeding point is eventually increased to an extremely large number of first power feeding paths. (Claim 1).

Also in claim 2, "return" in the feeding direction.
There is no. In addition, since the power feeding path that passes through the branch points with the power distribution ratio exceeding 1.5: 1 has two or more branch points such that there is one or more at each of the branch destinations, each branch point Even if the power distribution ratio is low, the power at the power feeding point can be finally distributed to an extremely large number of first power feeding paths.

Since the configuration according to claim 1 or 2 has 16 or more array antennas, it is possible to form a second power feeding path for distributing power from one power feeding point to 16 or more first power feeding paths. (Claim 3). In addition, if there are four or more branch points with a distribution ratio exceeding 2.5: 1, even if the power distribution ratio at each branch point is small, the power at the power feeding point will be extremely large in the end. It can be distributed to the power supply lines (claim 4).

An antenna device having these array antennas is effective for an antenna device having a plurality of microstrip array antennas, which is constructed by arranging conductors on the surface of a dielectric substrate having a ground conductor plate on the back surface ( Claim 5). The plurality of antenna elements are arranged at predetermined intervals along at least one first side of the both sides of the first feed line, and the field emission edge lines form an angle of 45 degrees with respect to the length direction of the first feed line. Since it is connected and arranged so as to form the electric field, the electric field in the direction orthogonal to the electric field emission edge line can generate polarized waves oriented in a direction inclined by 45 degrees with respect to the first feed line. it can. This prevents reception of radio waves from an oncoming vehicle when used as an antenna for a vehicle radar. Further, by changing the width of the antenna element in correspondence with a predetermined excitation amplitude, it is possible to give a desired directivity. The electric field radiation edge line of the radiating antenna element is a part of the contour line of the radiating antenna element and is a side orthogonal to the direction of the radiated electric field (claim 6).

By forming the width of the antenna element into a strip shape smaller than its length, it is possible to obtain a single-mode polarized wave (claim 7). Since the antenna element has a rectangular shape and is connected to the feeding strip line only near one of its apex angles, the lengths of both parallel sides in the length direction are substantially the same, which causes polarization in the length direction. A single mode radio wave can be obtained, and directivity characteristics with a low cross polarization level can be obtained (claim 8). The width of the radiating antenna element required along the feed strip line to have directivity changes, that is, the width is distributed as a function of the position along the feed strip line, but this is required. By changing the shape of the radiating antenna element and the connection shape to the feeding strip line according to the width, an array antenna with small reflection at each element can be realized. Therefore, an array antenna element having high radiation efficiency or high reception sensitivity can be manufactured (claim 9).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to specific examples. The present application is not limited to these examples.

FIG. 1 shows a second feeding path 100 which is a main part of the antenna device according to the present invention. Note that the second power supply line having the original width is shown as a line for the sake of simplicity. In addition, the microstrip array antenna M ₁ -M ₁ connected to the second power feeding path 100 and including the antenna element and the first power feeding path.
M ₈ and m _{1 to} m ₈ are connection positions (input end point of the first power feeding path)
Only showing. The second feeding path 100 shown in FIG. 1 has 15 bifurcation points D ₀ , D ₁ , D ₂₁ , D ₂₂ , from the feeding point S.
1 through D _{31 to} D ₃₄ , d ₁ , d ₂₁ , d ₂₂ , d _{31 to} d ₃₄
Six microstrip array antennas M _{1 to} M ₈ , m
_It supplies power to _{1 to} m ₈ .

Power is supplied from the feeding point S to the two branch points D ₀ by the microstrip line, and the two branch points D ₁ and d ₁ are supplied.
Power is distributed to. From the two branch points D ₁ to the two branch points D ₂₁
Power is distributed to the D _{2 2} and. Electric power is distributed from the two branch points D ₂₁ to the two branch points D ₃₁ and D ₃₂ . The two branch point D ₂₂
From this, electric power is distributed to two branch points D ₃₃ and D ₃₄ . Thus, the 2-branch point D ₃₁ to the microstrip array antennas M ₁ and M ₂ , the 2-branch point D ₃₂ to the microstrip array antennas M ₃ and M ₄ , and the 2-branch point D ₃₃ to the microstrip array antennas M ₅ and M. ₆ , the power is distributed from the two-branch point D ₃₄ to the microstrip array antennas M ₇ and M ₈ . The feeding path from the feeding point S to each of the microstrip array antennas M _{1 to} M ₈ is composed of only the x-axis positive direction and the y-axis positive direction in the figure.
There is no "return" as in (c). Therefore, each of the first feeding paths of the microstrip array antennas M _{1 to} M ₈ is
Since "return" does not occur in the power feeding path even when tilted in the positive direction of the x axis in FIG. 1 or slightly in the positive direction of the y axis, transmission loss in the power feeding path can be minimized.

This means that from the feeding point S to the bifurcation point D ₀ ,
Also in the feeding path to the microstrip array antennas m _{1 to} m ₈ via d ₁ , d ₂₁ , d ₂₂ , d _{31 to} d ₃₄ ,
The same applies by replacing "the positive direction of the y-axis" with "the negative direction of the y-axis". In addition, fifteen two-branch points D ₀ ,
_{D 1, D 21, D 22} , D 31 ~D 34, d 1, d 21, d 22, d 31
~ D ₃₄ distributes power 1: 1 and is supplied to 16 microstrip array antennas M _{1 to} M ₈ and m _{1 to} m ₈ when the transmission loss in the second feeding path 100 is ignored. The power can be exactly the same. Therefore, conversely, 16 microstrip array antennas M ₁ ~
When designing the aperture plane distribution of the entire antenna elements of M ₈ and m _{1 to} m ₈ into a desired shape, there is almost no restriction due to the limit of the power distribution ratio. The degree of freedom increases. In addition, in the second feeding path 100 of FIG. 1, the feeding paths from the feeding point S to any of the microstrip array antennas (the input end points of the first feeding path thereof) pass through four branch points equally. ing. For example, the feeding path from the feeding point S to the microphone cross trip array antenna M ₁ is four branch points D ₀ , D ₁ , D ₂₁ , and D ₃₁ , and the feeding path from the feeding point S to the microphone cross trip array antenna M ₈ . Passes through four branch points D ₀ , D ₁ , D ₂₂ , and D ₃₄ .

FIG. 2 shows a second feeding path 200 which is a main part of the antenna device according to the present invention. In FIG. 2 as well, the second power feeding path 200 having the original width is shown as a line. Also,
The antenna element and the first element connected to the second feeding path 200
Microstrip array antenna M consisting of
_{1 to} M ₉ and m _{1 to} m ₉ show only connection positions (input end points of the first power feeding path). The second power supply path 200 shown in FIG.
Are 17 bifurcation points D ₀ , D ₁ , D ₂₁ , from the feeding point S.
D ₂₂ , D ₂₃ , d ₁ , d ₂₁ , d ₂₂ and d ₂₃ , and T ₁ ,
_{T 21, T 22, T 23} , t 1, t 21, 18 pieces of microstrip through t ₂₂ and t ₂₃ array antenna M ₁ ~M _9,
The electric power is supplied to m _{1 to} m ₉ .

Two branch points D from the feeding point S₀To Micros
Electric power is supplied by the trip line, and there are two branch points T₁And t₁
Power is distributed to. 2 branch points T₁From 2 branch point T_{twenty one}
And D₁Power is distributed to. 2 branch points T_{twenty one}From mic
Loslip array antenna M ₁And 2 branch points D_{twenty one}To power
Is distributed, and the two branch points D_{twenty one}From Microstrip
Ray antenna M₂And M₃Power is distributed to. 2 branch points D
₁From 2 branch point T_{twenty two}And T_{twenty three}Power is distributed to. 2 minutes
Point T_{twenty two}From the microstrip array antenna M_Four
And 2 branch points D_{twenty two}Power is distributed to the two branch points D_{twenty two}From
Microstrip array antenna M_FiveAnd M₆Power is
Will be distributed. 2 branch points T_{twenty three}From the microstrip array
ー Antenna M₇And 2 branch points D_{twenty three}Power is distributed to
Point D_{twenty three}From the microstrip array antenna M₈
And M₉Power is distributed to. Each micros from the feeding point S
Trip array antenna M₁~ M₉The power supply route to
This is also composed of only the path in the positive x-axis direction and the positive y-axis direction
However, there is no “return” as shown in FIG. Yo
Microstrip array antenna M₁~ M₉Each of
The first power supply path is in the positive direction of the x-axis in FIG. 1 or more than that.
Even if it is slightly tilted to the positive side of the y-axis, the
To minimize transmission loss in the power supply line.
Can be suppressed.

This means that the feeding point S is divided into two branch points D.₀,
d₁, D_{twenty one}, D_{twenty two}And d_{twenty three}, And t₁, T_{twenty one}, T_{twenty two}Over
And t_{twenty three}Through microstrip array antenna m₁
~ M₉Even in the power supply path to the
Exactly the same as when read as "negative direction of y-axis"
One. It should be noted that 9 2-branch points D₀, D₁, D_{twenty one}, D_{twenty two}, D_{twenty three},
d ₁, D_{twenty one}, D_{twenty two}, D_{twenty three}Distributes power 1: 1 and 8
2 branch points T₁, T_{twenty one}, T_{twenty two}, T_{twenty three}, T₁, T_{twenty one}, T_{twenty two},
t_{twenty three}If the power is distributed 2: 1 then the second feed line 2
18 micros if the transmission loss at 00 is ignored
Strip array antenna M₁~ M₉, M₁~ M₉Supplied to
The power supplied can be exactly the same. In addition, 2 branch points
T₁, T_{twenty one}, T_{twenty two}, T_{twenty three}, T₁, T_{twenty one}, T_{twenty two}, T_{twenty three}smell
It is clear which of these two powers will be distributed to which one
But there is, for example, a two-branch point T₁At the branch point D₁To 2
Power, branch point T_{twenty one}1 power is distributed to two branch points T_{twenty one}
And so on, branch point D_{twenty one}2 power, etc. to Microstri
Up antenna M₁Achieved by distributing 1 power to
Be done. Therefore, conversely, 18 microstrip arrays
Antenna M₁~ M₉, M₁~ M₉The entire antenna element
When designing the aperture surface distribution to have a desired shape, the power distribution ratio
There are almost no restrictions due to limits,
The degree of freedom in designing the mouth distribution shape is increased. In addition, the second salary of FIG.
In the electric path 200, for example, a two-branch point T₁Izu
There is a branch point with a distribution ratio of more than 1.5: 1 also in these routes
To do. That is, the two branch points T₁Branch point T_{twenty one}Is the distribution ratio
2: 1 and D on the other end₁Distributed further on
2: 1 ratio of branch point T_{twenty two}, T_{twenty three}There is a power supply path that passes through
To do. Thus, in the second power feeding path 200 of FIG.
Has a distribution ratio of over 1.5: 1 beyond
There are two or more branch points that have power supply paths that pass through the branch points.
Exists and they are D₀, T₁, T₁, D₁, D₁Is.

FIG. 3 shows a second feeding path 300 which is a main part of the antenna device according to the present invention. Also in FIG. 3, the second power feeding path 300 having the original width is shown as a line. Also,
The antenna element and the first antenna connected to the second power feeding path 300
Microstrip array antenna M consisting of
_{1 to} M ₈ and m _{1 to} m ₈ show only the connection positions (input end points of the first power feeding path). Second power supply path 300 shown in FIG.
Are 15 bifurcation points D ₀ , D ₁ , Q ₂₁ , from the feeding point S.
_{T 21, D 21, Q 22} , T 22, D 22, d 1, q 21, t 21, d
Power is supplied to 16 microstrip array antennas M _{1 to} M ₈ and m _{1 to} m ₈ via ₂₁ , q ₂₂ , t _22, and d ₂₂ .

Power is supplied from the feeding point S to the two branch points D ₀ by a microstrip line, and the two branch points D ₁ and d ₁ are supplied.
Power is distributed to. From the two branch points D ₁ to the two branch points Q ₂₁
And power is distributed to Q _{2 2} . Power is distributed from the two-branch point Q ₂₁ to the microstrip array antenna M ₁ and the two-branch point T _21, and power is distributed from the two-branch point T ₂₁ to the microstrip array antenna M ₂ and the two-branch point D ₂₁ . Two
Microstrip array antenna M from branch point D ₂₁
Power is distributed to ₃ and M ₄ . Electric power is distributed from the 2-branch point Q ₂₂ to the microstrip array antenna M ₅ and the 2-branch point T _22, and power is distributed from the 2-branch point T ₂₂ to the microstrip array antenna M ₆ and the 2-branch point D ₂₂ . Two
Microstrip array antenna M from branch point D ₂₂
Power is distributed to ₇ and M ₈ . The feeding paths from the feeding point S to each of the microstrip array antennas M _{1 to} M ₈ are composed of only the paths in the positive x-axis direction and the positive y-axis direction in FIG. 9C. There is no such "return". Therefore, even if the first feeding path of each of the microstrip array antennas M _{1 to} M ₈ is tilted toward the positive direction of the x-axis in FIG. Is not generated, the transmission loss in the power feeding path can be minimized.

This means that from the feeding point S to the bifurcation point D ₀ ,
_{d 1, q 21, t 21} , d 21, also in the power supply path to the microstrip array antenna m ₁ ~m ₈ through q _22, t ₂₂ and d _22, "y axis" positive direction of the y-axis " It is exactly the same by substituting "negative direction of". In addition, the seven 2-branch points D ₀ , D ₁ , D ₂₁ , D ₂₂ , d ₁ , d ₂₁ , and d ₂₂ are 1: 1.
Distributes power to the four second branch point _{T 21, T 22, t 21} , t
₂₂ distributes the power 2: 1 and four 2 branch points Q ₂₁ ,
If Q ₂₂ , q ₂₁ , and q ₂₂ distribute power in a ratio of 3: 1, if the transmission loss in the second power feeding path 300 is ignored, then 16
Microstrip array antennas M _{1 to} M ₈ , m ₁
The power supplied to ~ m ₈ can be exactly the same. Incidentally, 2 either in a two branch point _{T 21, T 22, t 21} , t 22, either on whether to distribute a power, 2 branch points _{Q 21, Q 22, q 21} , either the 3 at q ₂₂ either To 1
It is clear whether to distribute the power of. For example, 2 branch points Q
_{At 21} , the power of 3 to the branch point T ₂₁ and the power of ₁ to the microstrip antenna M ₁ are distributed, and at the two branch point T ₂₁ , the power of 2 to the branch point D ₂₁ and the power of 1 to the microstrip antenna M ₂ . Is achieved by distributing. Therefore, conversely, 16 microstrip array antennas M
When designing the aperture plane distribution of the entire antenna elements of _{1 to} M ₈ and m _{1 to} m ₈ into a desired shape, there is almost no restriction due to the limit of the power distribution ratio. The degree of freedom in design increases. In addition, the second power feeding path 300 of FIG.
, There are four branch points Q ₂₁ , Q ₂₂ , q ₂₁ and q ₂₂ having a distribution ratio exceeding 2.5: 1.

FIG. 4 is a main part of the antenna device according to the present invention.
The second power feeding path 400 is shown. Originally in FIG.
The second feed line 400 having a width is shown as a line. Well
And an antenna element connected to the second feeding path 400
Microstrip array antenna consisting of the first feeding path
Na M₁~ M₁₆, M₁~ M₁₆Shows only the connection position. Figure
The second power feeding path 400 shown in 3 is 31 from the power feeding point S.
2 fork point D₀, Q₁, T ₁, D₁, Q_{twenty one}, T_{twenty one}, D_{twenty one}, Q
_{twenty two}, T_{twenty two}, D_{twenty two}, Q_{twenty three}, T_{twenty three}, D_{twenty three}, Q_{twenty four}, T_{twenty four},
D_{twenty four}, Q₁, T₁, D₁, Q_{twenty one}, T_{twenty one}, D_{twenty one}, Q_{twenty two},
t_{twenty two}, D_{twenty two}, Q_{twenty three}, T_{twenty three}, D_{twenty three}, Q_{twenty four}, T_{twenty four}And d_{twenty four}To
32 microstrip array antennas M through₁
~ M₁₆, M₁~ M₁₆To supply power to. The details
Is almost the same as that shown in FIGS. 1, 2 and 3,
The transmission loss is minimized in the second power supply line 400.
And ignore the transmission loss in the second power supply path 400
32 microstrip array antennas M₁
~ M₁₆, M₁~ M₁₆Can supply power equal to
Is.

As a concrete example of the antenna element, its plan view and sectional view are shown in FIGS. 5 (a) and 5 (b), respectively. The first feeder 12 and the antenna element 13 are provided on the front surface of the dielectric substrate 11 by strip conductors, and the ground conductor 14 is provided on the back surface. The antenna element 13 has a strip shape having a length L and a width W, is inclined at an angle of 45 degrees with respect to the length direction of the linear first feeding path 12, and is connected at its root portion. With this structure, it is possible to radiate linearly polarized waves at an angle of 45 degrees to the first power feeding path 12. Further, depending on the width W of the antenna element 13,
It is possible to control the power radiated from
The larger is, the larger the radiated power is. Further, the length L of the antenna element 13 is a resonance length, that is, approximately λ _g /
2 (λ _g is the strip conductor propagation wavelength). Further, the distance d connecting the antenna element to the first feeding path 12 is set to approximately λ _g / 2.

However, in the structure of FIG. 5, if the width W of the antenna element 13 is increased in order to obtain a large radiation amount, the reflected power returning from the antenna element 13 to the input side also increases. Therefore, there arises a problem that the gain of the array antenna is reduced. Therefore, in order to obtain a large radiated power, the antenna element 23 shown in FIGS. 6 (a) and 6 (b) is effective. A first feed path 22 and an antenna element 23 are provided on the front surface of the dielectric substrate 21 by a strip conductor, and a ground conductor 24 is provided on the back surface. The antenna element 23 has a rectangular shape having a length L and a width W, is inclined 45 degrees with respect to the linear first feeding path 22, and is connected near the apex angle. With this structure, it is possible to radiate linearly polarized waves at an angle of 45 degrees to the first power feeding path 22. Further, the reflected power returning to the input side can be made smaller than that of the antenna element 13 of FIG. Therefore, a high gain array antenna can be realized. Further, the power radiated from the antenna element 23 can be controlled by the width W of the antenna element 23, and the radiated power increases as the width W increases. The length L of the antenna element 23 is the resonance length, that is,
It is set to approximately λ _g / 2 (λ _g is the strip conductor propagation wavelength λ _g ). The distance d connecting the antenna element 23 to the strip conductor 22 is set to approximately λ _g / 2.

[0033] In FIGS. 1 to 4, an example of a feed line of the antenna device for supplying a power of 16 to 32 microstrip array antenna from a single feeding point, in FIG. 4, for example, M ₁ ~ Each of the portions shown as M ₁₆ , m _{1 to} m ₁₆ is divided into four by providing branches such as Q ₂₁ , T ₂₁ , and D ₂₁ of FIG. 4, and a total of 128 microstrip array antennas are provided. You may form the electric power feeding path of the antenna device which supplies electric power from a power feeding point.

Further, as shown in FIG. 7A, three-branch Th
May be provided. In order to form the three branches so that there is no “return”, in the direction parallel to the first feeding path from the feeding point S, as in the three branching points Th ₀ and Th ₁ of FIG. Must be connected in one row. Further, as shown in FIG. 7B, the second power feeding path may not be parallel or vertical after the branch of 1. In FIG. 7B, twelve microstrip array antennas M _{1 to} M ₆ parallel to the x-axis direction.
And to m ₁ ~m _6, shows a second feed line having a parallel feed path segment in the forward direction to the direction of 60 degrees ± the x-axis. It is obvious that, for each feed path, the orthogonal projections of the feed path segments are the same vector in a slanting direction.

In the above example, the antenna device having the feeding point S near the center of the side of the antenna device is illustrated. However, the right half in FIGS. 1, 2, 3, and 4, and FIG. 7B. In the above, only the upper half (in each case, a branch point or the like is a capital part) may be configured. In the present invention, the feeding point may be at any position on the side of the antenna device, and is not limited to the vicinity of the center of one side.

Although the strip-shaped antenna element and the rectangular-shaped antenna element have been described with reference to FIGS. 5 and 6, two types of antenna elements may be mixed in one microstrip array antenna. That is, the antenna element having the structure shown in FIG. 5 is used in the region where the radiation amount is small, and the antenna element having the structure shown in FIG. 6 is used in the region where the radiation amount is large. As a result, a high-gain array antenna with a small amount of reflection can be realized.

The length L of the antenna element is approximately λ _g /
Although it is set to 2, it may be any integer multiple. Further, the interval for connecting the antenna element to the strip conductor is approximately λ _g / 2, but it may be any integral multiple of this. Further, although the antenna elements are provided on both sides of the strip conductor, they may be provided on only one side.

[Brief description of drawings]

FIG. 1 is a second feed line 10 of an antenna device according to the present invention.
The conceptual diagram which shows the structure of 0.

FIG. 2 is a second feeding path 20 of the antenna device according to the present invention.
The conceptual diagram which shows the structure of 0.

FIG. 3 is a second power feeding path 30 of the antenna device according to the present invention.
The conceptual diagram which shows the structure of 0.

FIG. 4 is a second power feeding path 40 of the antenna device according to the present invention.
The conceptual diagram which shows the structure of 0.

5A is a plan view showing a configuration of an antenna element of an antenna device according to the present invention, and FIG. 5B is a sectional view thereof.

6A is a plan view showing another configuration of the antenna element of the antenna device according to the present invention, and FIG. 6B is a sectional view thereof.

FIG. 7 (a) is a conceptual diagram showing a configuration of a second feeding path of the antenna device according to the present invention utilizing three branches, (b).
[Fig. 3] is a conceptual diagram showing a second power supply line having a portion forming an angle of ± 60 degrees with respect to the first power supply line.

FIG. 8 is a perspective view showing a conventional example of an antenna device using a microstrip conductor.

FIG. 9 is a conceptual diagram showing a conventional example of a second feeding path of the antenna device.

FIG. 10 is a conceptual diagram showing another conventional example of the second feeding path of the antenna device.

FIG. 11 is a relationship diagram between the width w of the microstrip line and the impedance Z ₀ by simulation.

FIG. 12 is an explanatory diagram for forming a branch from a 50Ω microstrip line to two 50Ω microstrip lines at a power ratio of 4: 1.

[Explanation of symbols]

S Feed point D _i , D _jk , d _i , d _jk Two-branch point with power ratio 1: 1 T _i , T _jk , t _i , t _jk Two-branch point Q _i , Q _{jk with} power ratio 2: 1, q _{jk i} , q _jk 2-branch point M _i , m _{i with a} power ratio of 3: 1, micro strip array antenna 11, 21 dielectric substrate 12, 22 first feeding path 13, 23 antenna element 14, 24 ground conductor plate

Claims (9)

(57) [Claims] 1. An array antenna comprising a plurality of antenna elements connected to a linear first feed line, the array antennas being parallel to each other, and the plurality of first antennas. An antenna device having a second feeding path formed with a branch point so as to supply power from one feeding point near the outer periphery of the device to each input end point of the feeding path of the second feeding path. Is a feed path that is not parallel to the first feed path when the feed path and the arbitrary input end point of the first feed path are decomposed into feed path segments at branch points and direction change points. The path segment is a vector in which the orthogonal projections have the same direction, and the second feed line is the first feed line to which the arbitrary feed line passes from the feed point through three or more branch points. 1
An antenna device which reaches the input end point of the power feeding path of the. 2. An array antenna having a plurality of antenna elements connected to a linear first feed line, and a plurality of array antennas arranged so that the first feed lines are parallel to each other, and the plurality of first antennas. An antenna device having a second feeding path formed with a branch point so as to supply power from one feeding point near the outer periphery of the device to each input end point of the feeding path of the second feeding path. Is a feed path that is not parallel to the first feed path when the feed path and the arbitrary input end point of the first feed path are decomposed into feed path segments at branch points and direction change points. The path segment is a vector in which the mutually orthogonal projections have the same direction, and the second power feeding path passes through a branch point where the power distribution ratio exceeds 1.5: 1, and the first power feeding path. The power supply path that reaches the input end point of Having a branch point such as in any preceding also present one or more two or more antenna apparatus characterized. 3. The antenna device according to claim 1, comprising 16 or more array antennas. 4. The antenna device according to claim 1, further comprising four or more branch points having a power distribution ratio exceeding 2.5: 1. 5. A conductor is arranged on the surface of a dielectric substrate having a ground conductor plate on the back surface, the array antenna is a microstrip array antenna, and the feeding point is the surface of the dielectric substrate. The antenna device according to any one of claims 1 to 4, wherein the antenna device is disposed in the vicinity of the outer periphery of the antenna device. 6. The microstrip array antenna according to claim 1, wherein the field emission edge lines are arranged at predetermined intervals along at least one first side of both sides of the first feeding path with respect to a length direction of the feeding strip line. The antenna elements are connected and arranged from the sides thereof so as to form an angle of 45 degrees, and the antenna element is a radio wave wavelength propagating through the first feeding line at an operating frequency whose length is preset. About 1 /
It is an integral multiple of 2, and has a width distribution corresponding to the position-related distribution of the excitation amplitude of each antenna element, the width of which is preset so as to provide a desired directional characteristic, and one end of which has the first feed line. The antenna device according to claim 5, wherein the antenna device is formed of a strip conductor that is connected to and is open at the other end. 7. The antenna device according to claim 6, wherein the antenna element has a strip shape whose width is smaller than its length. 8. The antenna device according to claim 6, wherein the antenna element has a rectangular shape, and is connected to the first feeding path only in the vicinity of one apex angle of the rectangular shape. 9. The antenna element, in the width distribution, in a region where the width of the antenna element is narrowed,
A strip-shaped element having the same width from the root portion and being connected to the first power feeding path and having a width smaller than the length, and in a region where the width of the antenna element is widened, the first element is provided only near the apex angle. The antenna device according to claim 6, wherein the antenna device is a rectangular element connected to the power feeding path.