JPH06152235A - Plane array antenna - Google Patents

Abstract

PURPOSE:To obtain the plane array antenna for two orthogonal polarized waves with simple structure by forming an antenna element group being an aperture group to a ground conductor layer and forming the antenna elements with open holes of a simple shape such as a circle. CONSTITUTION:Tips of strip conductor layers 2, 3 are arranged orthogonal to each other to extract one linearly polarized wave component in two orthogonal polarized waves included in a received wave externally via a 1st feeder. Then the other linearly polarized wave component is extracted externally via a 2nd feeder. As to other apertures 1b, 1c... and tips 2b, 2c..., 3b, 3c... of the tips of the strip conductors, the tips of the strip conductor layers 2, 3 corresponding to each other are almost overlapped in the vertical direction in the center of the relevant apertures. Then the tips of the strip conductor layers 2, 3 corresponding to each other are arranged to be orthogonal within a horizontal plane, then the selectivity of each of the two orthogonal polarized wave components is secured. Thus, the broad band two orthogonal polarized wave antenna with high compatibility with each layer is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar array antenna used as a receiving antenna for satellite broadcasting and communication satellites.

[0002]

2. Description of the Related Art As a receiving antenna for satellite broadcasting or satellite communication, a planar array antenna is under development in place of the conventional parabolic antenna in order to simplify and reduce the cost. Further, as radio waves transmitted from the communication satellite, two linearly polarized waves orthogonal to each other are combined in order to double the frequency utilization efficiency.

Horizontal of the radio wave transmitted from the communication satellite
An example of a planar array antenna for receiving vertically polarized waves is B-123, "Two-polarization planar array antenna for receiving communication satellites," published in the proceedings of the 1992 IEICE Spring Conference. It is described in the draft. As shown in FIG. 11, this planar array antenna includes a first layer 61 on which an aperture element is formed, an upper feeder line and a second layer 62 on which a conductor element (electromagnetic coupling element) is formed at the tip portion, and an electromagnetic coupling. Layer 6 having slot elements formed therein
3. The structure is such that the fourth layer 64 on which the lower power supply line is formed is laminated on the lower conductor plate 65, which is kept at the ground voltage, with an insulating layer of an appropriate thickness interposed.

Another example of a planar array antenna for receiving horizontal / vertical polarized waves transmitted from the communication satellite is
It is described in a draft by B. Ota et al. Entitled "Radiation characteristics of a dual-polarized triplate-fed planar antenna for polarization" published in the proceedings of IEICE Spring Conference 1992. This planar array antenna, as shown in FIG.
An upper layer slot plate 71 in which a rectangular slot group is formed,
A patch group for receiving signals of one polarization and an upper layer film substrate 72 on which a feeder line is formed, a lower layer slot plate 73 on which rectangular slots are formed, and a patch group for receiving signals of the other polarization. Lower layer film substrate 74 on which electric wires are formed
Is laminated on the lower conductor plate 75 which is kept at the ground voltage.

[0005]

In the prior art planar array antenna shown in FIG. 11, the shapes of the apertures and patches formed in each layer are different, so it takes time and labor to process and the compatibility of each layer is high. However, there is a risk that the cost will increase and the manufacturing yield will decrease due to the lack of

In the prior art planar array antenna shown in FIG. 12, the upper and lower film substrates 7 in which patches functioning as antenna elements are arranged at the tip of the feeder line.
Since 2, 74 are used, there is a problem that the structure of each film substrate becomes complicated. Further, since the antenna of FIG. 12 has the feed line and the patch formed on a common substrate, the "HANDBOOK OF MICR" issued by WILEY-INTERSCIENCE
OWAVE AND OPTICAL COM-PONENTS Volume 1 "pp 841
As described in (1), there is a problem that the flexibility in design is reduced and the radiation characteristics are deteriorated in the millimeter wave band. In addition, since the patch is used as the antenna element, a ground conductor layer that constitutes a feeding microstrip line or a triplate line is separately required, which causes an increase in the number of layers and a problem that the structure becomes complicated. .

Therefore, one object of the present invention is to provide a planar array antenna for orthogonal two polarizations having a simple structure. Another object of the present invention is to provide a plane array antenna for orthogonal two polarizations with high compatibility between layers. Still another object of the present invention is to provide a planar array antenna for orthogonal two polarizations, which is highly flexible in design, in which an antenna element and a feed line are formed in different layers. Yet another object of the present invention is to provide a wideband orthogonal dual polarized plane array antenna.

[0008]

In a planar array antenna of the present invention, an antenna element group having an opening group formed in a ground conductor layer and a plurality of tip portions branched near these antenna element groups are made substantially orthogonal to each other. While extending above and below the ground conductor layer and parallel to this ground conductor layer, first and second
And the first and second feeder lines having the strip conductor layer of.

[0009]

According to the planar array antenna of the present invention, the two systems in which the respective components of the two polarizations arriving at the antenna element group having the aperture group formed in the ground conductor layer are arranged with their tip portions substantially orthogonal to each other Is selectively received by each of the power supply lines and is led to the outside. The feed line of each system is in the form of a microstrip line or a triplate line having first and second strip conductor layers arranged in parallel with each other with a ground conductor layer having an opening group forming an antenna element group interposed therebetween. Is formed by.

[0010]

1 is an exploded perspective view showing a part of a planar array antenna according to an embodiment of the present invention, in which 1 is a ground conductor layer and 2 is a ground conductor layer.
Is a first strip conductor layer, 3 is a second strip conductor layer, and 4 is a second lower ground conductor layer.

The ground conductor layer 1 and the first strip conductor layer 2 which is arranged above the ground conductor layer 1 with a constant space therebetween provide a microstrip line type first feeder line (feeder).
Is formed. In addition, the ground conductor 1, the second strip conductor layer 3 arranged below the ground conductor 1 with a constant space, and the lower ground conductor layer 4 arranged further below the ground conductor 1 form a second triplate line type second conductor. A feeder line (feeder) is formed. The first and second strip conductor layers 2 and 3 are extended up and down to a plurality of tip portions while repeating branching above and below the ground conductor layer 1, and the root sides of the strip conductor layers 2 and 3 are appropriately arranged such as coaxial lines and waveguide lines. It is connected to the receiver via a model line.

At a location on the ground conductor layer 1 facing the tip portions of the first and second power supply lines, a group of openings 1a, 1b, 1 called circular slits, slots or apertures.
An antenna element group consisting of c ... Is formed. Openings 1a formed in the ground conductor layer 1 and tip portions 2a, 3 of the strip conductors formed in the strip conductor layers 2, 3
As shown in the plan view of FIG. 4 and the cross-sectional view of FIG. 5, a indicates that the tip portions 2a and 3a of the strip conductor substantially overlap with each other in the vertical direction (Z-axis direction) at the center of the opening 1a, and 2a and 3a are horizontal planes (XY
Are arranged so as to be orthogonal to each other in the plane. The lower ground conductor layer 4 functions as a reflection plate that propagates a radiated radio wave upward only.

As described above, by arranging the tip portions of the strip conductor layers 2 and 3 so as to be orthogonal to each other, one linear polarization component of the two orthogonal polarizations included in the received wave is the first feed line. And the other linearly polarized wave component is extracted to the outside via the second power supply line. Other openings 1b, 1c ... And the tip portion 2b of the strip conductor,
2c ..., 3b, 3c ... Similarly, the corresponding tip portions of the strip conductor layers 2 and 3 substantially vertically overlap at the centers of the corresponding openings, and the strip conductor layers 2 and 3 correspond to each other. By arranging the tip portions so as to be orthogonal to each other in the horizontal plane, the selectivity with respect to each of the two orthogonal polarization components is secured.

The diameter of the openings 1a, 1b, 1c, ... Is a value of about 13 mmφ, which corresponds to almost a half wavelength of the received radio waves, assuming reception of radio waves from broadcasting satellites or communication satellites in the frequency band of 11 GHz to 12 GHz. Is set to. The distance between the ground conductor layer 1 and the first strip conductor layer 2 is set to an appropriate value in consideration of the impedance of the microstrip line. This interval is set to a value smaller than the wavelength of the received radio wave, for example, a value of about 2 mm.

The distance between the second strip conductor layer and the ground conductor layers 1 and 4 above and below it are between the impedance of the triplate line and the aperture groups 1a, 1b, 1c. It is set to an appropriate value considering the distance. In order to set the intervals between the layers 1, 2, 3, and 4, a dielectric layer such as expanded polystyrene having a low relative dielectric constant of about 1.1 is interposed between the layers, or an appropriate place such as four corners of each layer. A columnar spacer or the like is installed in. The width of each tip of the strip conductor is set to an appropriate value in consideration of the impedance of the line, for example, a value of about 3 mm.

FIG. 2 is an exploded perspective view showing a part of a planar array antenna according to another embodiment of the present invention, in which 1 is a ground conductor layer, 2 is a first strip conductor layer, and 3 is a second strip. The conductor layers 4, 4 are lower ground conductor layers, and 5 are upper ground conductor layers.

The planar array antenna shown in FIG. 2 is obtained by adding a second opening formed in the upper ground conductor layer 5 to each antenna element forming the planar array antenna shown in FIG. As shown in the cross-sectional view of FIG. 6, the opening groups formed in the respective conductor layers have the same diameter and are arranged so that their centers overlap in the vertical direction. That is,
According to this embodiment, each antenna element has a group of openings 1a, 1b, 1c, ... Formed in the ground conductor layer 1, a reflection plate formed by the lower ground conductor layer 4 disposed thereunder, and an upper ground conductor. .., which are formed in the layer 5.

As described above, by forming the opening groups constituting each antenna element from the opening groups of equal size which are vertically overlapped with each other, both the first and second feeder lines are vertically ground. The form of the triplate line in which the conductor layers are arranged can be unified, and the frequency characteristic can be broadened as described below.

FIG. 8 is experimental data showing the frequency characteristics of the planar array antenna having the structure shown in FIG.
The sweep frequency is from 9.5 GHz to 13.0 GHz, and the vertical axis at each frequency is the return loss (dB). The circle in the figure is the frequency region of interest, and the valleys at which the return loss is separated appear at points of 10.8 GHz and 11.1 GHz in this frequency region. It is considered that these valleys appear due to the double resonance occurring in each of the openings formed in the different ground conductor layers. Due to this double resonance characteristic, the reception frequency band is expanded.

In order to confirm the phenomenon of the double resonance, the return loss was measured for the structure in which the first strip conductor layer 2 and the upper ground conductor layer 5 above the first strip conductor layer 2 were removed from the structure of FIG. It was The experimental data is shown in FIG. In FIG. 9, the horizontal axis and the vertical axis are the same as in FIG.
It is the sweep frequency from GHz to 13.0 GHz and the return loss (dB) at each frequency. According to this structure,
The valley of the return loss is unified and this single valley moves to the point of 11.268 GHz on the high frequency side.

In this way, as the antenna element group, two groups of apertures having the same diameter are vertically overlapped to form two systems, so that a double resonance slightly generated due to the misalignment in the vertical direction is generated. As a result, the band of the antenna can be widened. By making the diameter of each opening group slightly different, 2
The individual resonance points may be further shifted to further widen the band.

FIG. 3 is an exploded perspective view showing a part of a planar array antenna according to still another embodiment of the present invention, where 1 is the first.
Ground conductor layer, 2 is a first strip conductor layer, 3 is a second strip conductor layer, 4 is a lower ground conductor layer, and 6 is a second ground conductor layer.

The planar array antenna of FIG. 3 can be seen as a vertical array antenna in which the first strip conductor layer 2 and the upper ground conductor layer 5 of the planar array antenna of FIG. 2 are interchanged in the vertical direction. Similarly to the above-mentioned one, each of the two groups of apertures arranged so as to be displaced in the height direction achieves a wide band due to double resonance.

In each of the embodiments shown in FIGS. 1, 2 and 3, the tip portions 2a, 3 of the first and second strip conductors are used.
The configuration in which a is arranged so as to intersect at the center of the opening 1a has been illustrated. However, when it is necessary to adjust the characteristics, the tip portions 2a and 3a of the strip conductors may be overlapped with each other at the center of the opening 1a as illustrated in FIG. 10A, or as illustrated in FIG. As illustrated,
Alternatively, the openings 1a may be arranged so as to overlap each other at a position decentered from the center.

Further, the present invention has been described in the case where the opening forming the antenna element is circular. However,
If desired, the opening may have a shape other than a circle, such as a square.

[0026]

As described above in detail, in the planar array antenna of the present invention, since the antenna element is composed of an aperture having a simple shape such as a circle, the plane for dual polarization having an extremely simple structure is provided. Array antenna is realized.

Further, in the planar array antenna of the present invention, as is clear from the embodiments shown in FIGS. 2 and 3, since the compatibility of each layer is high, the manufacturing yield is improved and the manufacturing cost is reduced. There are also advantages.

Further, since the planar array antenna of the present invention has a structure in which the aperture as the antenna element and the feed line are formed in different layers, the flexibility in design is increased and high performance characteristics can be realized. There is also.

Further, according to one embodiment of the present invention, there is also an advantage that a wide band characteristic utilizing double resonance can be realized with a simple structure and high compatibility.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing the configuration of part of a planar array antenna according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a partial configuration of a planar array antenna according to another embodiment of the present invention.

FIG. 3 is an exploded perspective view showing a partial configuration of a planar array antenna according to still another embodiment of the present invention.

FIG. 4 is a plan view showing a structure of each antenna element of FIG.

5 is a cross-sectional view showing the structure of each antenna element of FIG.

FIG. 6 is a cross-sectional view showing the structure of each antenna element of FIG.

7 is a cross-sectional view showing the structure of each antenna element of FIG.

8 is experimental data showing characteristics of the planar array antenna of FIG.

FIG. 9 is another experimental data set for comparison with the experimental data set in FIG.

10 is a plan view showing another structure of each antenna element of FIGS. 1, 2 and 3. FIG.

FIG. 11 is an exploded perspective view showing a configuration of an example of a conventional planar array antenna.

FIG. 12 is an exploded perspective view showing the configuration of another example of the conventional planar array antenna.

[Explanation of symbols]

1 Ground conductor layer (first ground conductor layer) 1a to 1d Opening group formed in ground conductor layer 1 First strip conductor layer 2a to 2d Tip part of first strip conductor layer 3 Second strip conductor Layers 3a to 3d Tip part of second strip conductor layer 4 Lower ground conductor layer 5 constituting reflector of antenna element group 5 Upper ground conductor layer 5a to 5d Opening group 6 Second ground conductor layer 6a to 6d Opening group

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takushi Okita 2-6-3 Otemachi, Chiyoda-ku, Tokyo Within Nippon Steel Corporation (72) Innovator Motonobu Moriya 2-6-Otemachi, Chiyoda-ku, Tokyo No. 3 within Nippon Steel Corporation

Claims (7)

[Claims] 1. A planar array antenna for transmitting and receiving radio waves including two orthogonal polarized waves, comprising: an antenna element group having an opening group formed in a ground conductor layer; and a plurality of branched tip portions of the antenna element. First and second feeder lines having first and second strip conductor layers extending above and below the ground conductor layer and in parallel with the ground conductor layer while being substantially orthogonal to each other in the vicinity of the group, A planar array antenna characterized by having. 2. The planar array antenna according to claim 1, wherein the antenna element has a reflection plate composed of a lower ground conductor layer arranged below the second strip conductor layer. 3. The opening according to claim 2, wherein the opening forming the antenna element group includes an opening group formed in an upper ground conductor layer arranged above the first strip conductor layer. Planar array antenna. 4. The ground conductor layer according to claim 1, wherein the ground conductor layer is composed of two ground conductor layers that are vertically opposed to each other, and the opening group is formed to face each of these ground conductor layers. A planar array antenna comprising two groups of aperture groups. 5. The planar array antenna according to claim 1, wherein the group of apertures forming the group of antenna elements is circular. 6. The planar array antenna according to claim 3, wherein the aperture groups formed in the different ground conductor layers are circular with the same diameter. 7. The planar array antenna according to claim 3, wherein the aperture groups formed in the different ground conductors are circular with different diameters.