JP5633097B2 - Stacked two-dimensional slot array antenna - Google Patents

Description

  The present invention relates to millimeter-wave band antenna technology.

  In recent years, research and development of ultrahigh-speed wireless communication technology using millimeter-wave band radio waves has been underway. Millimeter-wave radio has a high directivity and a large free space propagation loss. For high-speed communication, it is necessary to narrow the beam using an array antenna with high directivity.

  Various array antennas exist depending on the structure, but the laminated two-dimensional slot array antenna using a hollow waveguide structure realizes an antenna device with high efficiency and high gain because the loss on the feed line is low. it can.

  5 to 7 are diagrams showing a conventional structure (first example) of a stacked two-dimensional slot array antenna. This stacked two-dimensional slot array antenna 1 has a structure in which metallic thin plates are stacked in layers, and a radio wave feeding path is formed by each layer.

  This feed line is coupled to a waveguide distributor 11 that distributes radio waves in the rectangular waveguide 3 from the connection side with the rectangular waveguide 3 toward the external space, and to the cavity at the antenna opening end. Coupling slot 12, a cavity 13 for exciting the slot antenna based on radio waves, and a rectangular slot antenna 14 formed in the outermost layer and arranged two-dimensionally.

  The plurality of slot antennas 14 are arranged and formed so that the shape of the outer edge surrounding them is a square, and one coupling slot 12 corresponds to the four slot antennas 14.

  Then, the coupling ends A of the waveguide distributors 11 coupled to the four coupling slots 12 are connected in the longitudinal direction of the slot antenna 14, and the connection units B are further connected in the short direction of the slot antenna 14. Then, the connection parts are further connected in the longitudinal direction, and finally, the parts are connected in the short direction, thereby forming one waveguide distributor 11 having the same length in the plane, and forming the bottom layer Is connected to one rectangular waveguide 3 at the center of the.

  FIG. 8 is a diagram showing a second example. In the case of the first example, if the orientation of the antenna device fluctuates from the installation position due to the high directivity of the slot antenna 14 due to an earthquake or the like, it takes time to physically readjust the direction of the antenna device. End up.

  Therefore, in the second example, a plurality of slot antennas 14 are equally divided into four blocks BL in the longitudinal direction, and the connection units B in each block BL are connected in the longitudinal direction, thereby providing one waveguide distributor. 11 is formed for each block BL.

  Then, one rectangular waveguide 3 is connected to each block BL, and the radiation direction of the radio wave is controlled by giving a phase difference to the radio wave signal supplied to each block BL. As a result, the antenna beam can be swung in any direction without shaking the antenna device itself, thereby preventing the above-described physical readjustment.

Yohei Miura, 4 others, “Double-Layer Full-Corporate-Feed Hollow-Waveguide Slot Array Antenna in the 60-GHz Band”, IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 59, NO. 8, AUGUST 2011, p. 2844-2851

  However, in the case of the second example, since the slot antenna groups are connected so that the short sides of the rectangular slot antenna 14 face each other, the antenna beam pattern deteriorates due to generation of side lobes.

  That is, as shown in FIG. 9, the electric field component output from the slot antenna 14 to the external space side (upward direction in the drawing) is strong at the center of its long side and weak at its end (short side). When the short sides of the slot antenna 14 are connected so as to face each other, the portions where the electric field components are weak are coupled to each other. Since it is radiated, the antenna beam pattern is deteriorated.

  The present invention has been made in view of the above circumstances, and an object thereof is to improve deterioration of an antenna beam pattern.

The stacked two-dimensional slot array antenna according to claim 1 is a stacked two-dimensional slot array antenna in which a metal layer is stacked and a hollow path for feeding radio waves is formed in each layer. A plurality of slot antennas arranged in a rectangular shape, and a slot antenna whose long sides face each other among a plurality of slot antennas formed in a lower layer than the uppermost layer and divided in a short direction of the slot antenna A waveguide distributor that spatially connects the ends of the cavity path corresponding to each other, and the waveguide distributor spatially connects the ends of the cavity path using a plurality of layers, The gist of the present invention is to have a first connecting means for spatially connecting the end portions with an upper layer, and a second connecting means for spatially connecting the first connecting means with a lower layer .

  As described above, according to the present invention, the plurality of slot antennas divided in the short direction of the rectangular slot antenna are connected so that the long sides of the slot antenna face each other. The coupling can suppress the deterioration of the antenna beam pattern.

  According to the present invention, it is possible to suppress degradation of the antenna beam pattern.

FIG. 3 is a layer top view of the stacked two-dimensional slot array antenna according to the first embodiment. It is a figure which shows the connection part of a 1st waveguide connection unit and a 2nd waveguide connection unit. It is a figure which shows the structural example of the connection part of a 1st waveguide connection unit and a 2nd waveguide connection unit. It is a layer top view of the laminated two-dimensional slot array antenna which concerns on 2nd Embodiment. It is a perspective sectional view of a conventional stacked type two-dimensional slot array antenna. FIG. 6 is a configuration explanatory diagram of a conventional stacked two-dimensional slot array antenna. It is a layer top view of the conventional laminated type two-dimensional slot array antenna (1st example). It is a layer top view of the conventional laminated type two-dimensional slot array antenna (2nd example). It is explanatory drawing of an effect of a laminated type two-dimensional slot array antenna.

  The present invention is characterized in that a plurality of slot antennas in divided blocks are connected by a waveguide distributor so that their long sides face each other. Thereby, portions having strong electric field components are coupled to each other in the plurality of slot antennas facing each other on the long sides, and a good antenna beam pattern without side lobes can be obtained, so that deterioration of the antenna beam pattern can be suppressed.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings. However, the present invention can be implemented in many different modes and should not be construed as being limited to the description of the present embodiment.

[First Embodiment]
FIG. 1 is a layer top view of the stacked two-dimensional slot array antenna 1 according to the first embodiment. FIG. 4A is a top view of the uppermost layer, and FIG. 4B is a top view of a formation layer of the waveguide distributor 11.

  The laminated two-dimensional slot array antenna 1 has a structure in which a thin metal plate or a thin plate with a dielectric surface covered with metal is laminated in layers, and a radio wave feeding path is formed by each layer. For example, it is used for an antenna device for a millimeter wave band of 120 GHz.

  In the same way as the prior art shown in FIG. 5 and FIG. 6, this feed line is formed in the rectangular waveguide 3 from the connection side with the rectangular waveguide 3 connected to the lowermost layer toward the external space side of the antenna device. A waveguide distributor 11 that distributes the internal radio wave, a coupling slot 12 that couples the radio wave to the cavity at the antenna opening end, a cavity 13 that excites the slot antenna based on the radio wave, and a two-dimensional shape formed on the outermost layer. The rectangular slot antennas 14 are arranged in a rectangular pattern. The sizes of these constituent elements are approximately the same as the parameter values described in TABLEI of Non-Patent Document 1.

  The plurality of slot antennas 14 are arranged and formed so that the shape of the outer edge surrounding them is a square. In order to divide the output areas of the four radio signals having different phases, the slot antennas 14 are arranged in the short direction of the slot antenna 14. Units are equally divided into two blocks BL. The four slot antennas 14 correspond to one coupling slot 12.

  The waveguide distributor 11 includes a first waveguide connection unit 11a and a second waveguide connection unit 11b having different formation layers. The plurality of slot antennas 14 included in the block BL are The slot antennas 14 are connected so that the long sides face each other.

  Specifically, in one block BL, the first waveguide connection unit 11a connects the coupling ends (distribution ends) A of the waveguide distributor 11 coupled to the four coupling slots 12. The same layer (upper intermediate layer) as the formation layer of the coupling end A is connected in the short direction of the slot antenna 14.

  Further, the second waveguide connection unit 11b is configured such that the first waveguide connection units 11a are connected to each other in the slot antenna 14 on the lower layer (lower intermediate layer) of the formation layer of the first waveguide connection unit 11a. Connect in the short direction. The second waveguide connection unit 11b is connected to one rectangular waveguide 3 prepared for each block.

  That is, the waveguide distributor 11 uses the waveguide distributor structure coupled to the four coupling slots 12 as one unit in order to divide the plurality of slot antennas 14 into four in the short direction. Two first waveguide connection units 11a connected to each other, and the first waveguide connection units 11a are connected to each other by using a second waveguide connection unit 11b in the lower layer. And connect in the short direction.

  In this way, since the plurality of slot antennas 14 in the divided block BL are connected by the waveguide distributor 11 so that the long sides of the slot antenna 14 face each other, the plurality of slot antennas that face each other along the long sides. In FIG. 14, the portions having strong electric field components are coupled to each other, so that a good antenna beam pattern without side lobes can be obtained, so that deterioration of the antenna beam pattern can be suppressed.

  Further, since the plurality of slot antennas 14 in the divided block BL are connected using a plurality of layers, a planar collision between the waveguide distributors 11 in the adjacent blocks BL can be avoided. This point will be described below.

  When connecting the plurality of slot antennas 14 in the block BL so that the long sides of the slot antenna 14 face each other, when connecting so that the short sides as shown in FIGS. 7B and 8B face each other Unlike the waveguide distributor 11, the coupling ends A of the waveguide distributors 11 need to be detoured and connected to each other, and thus interfere with the waveguide distributor 11 of the adjacent block BL.

  Therefore, the interference state is avoided by using a plurality of upper and lower layers. On the other hand, it is conceivable to reduce the thickness of the waveguide distributor 11, but the waveguide distributor 11 requires a certain thickness.

  The thickness of the waveguide has a trade-off relationship with the cutoff frequency of the waveguide and a higher-order mode, and electromagnetic waves having a cutoff frequency or lower cannot be propagated. Further, when the waveguide is thin, the cutoff frequency increases.

  In other words, if the waveguide is narrowed to avoid structural collisions, it cannot propagate unless it has a higher frequency electromagnetic wave. On the other hand, in a design in which the cutoff frequency of the waveguide is limited to the vicinity of the use frequency, the electromagnetic wave can pass through, but the group delay characteristic in the use frequency band varies.

  Therefore, it is necessary to set the waveguide thickness to a cutoff frequency that is sufficiently lower than the used frequency to some extent. On the other hand, if the waveguide becomes thicker, an unnecessary electromagnetic wave mode, which is a higher-order mode, is generated, which causes noise. Therefore, an appropriate waveguide thickness considering these factors is required.

  Therefore, by using a plurality of upper and lower layers, a plane collision between the waveguide distributors 11 in the adjacent blocks BL can be avoided while ensuring an appropriate thickness in the formation of the waveguide distributor 11. ing.

  The waveguide distributor 11 must have the same distance from the connection end to the rectangular waveguide 3 to each coupling end A, that is, the external space side (in the space of FIG. 1). Since it is necessary to connect the second waveguide connection unit 11b to a position where the first waveguide connection unit 11a is divided into two equal parts as viewed from above, the first waveguide connection unit 11a and the second waveguide connection unit 11a It is difficult to connect the waveguide connection units 11b at the shortest distance on the same layer.

  Then, the connection part of the 1st waveguide connection unit 11a and the 2nd waveguide connection unit 11b is shown in FIG. The feed line of the first waveguide connection unit 11a and the feed line of the second waveguide connection unit 11b are spatially connected via a hollow coupling slot 11c formed of a thin layer.

  As a connection means for such a connection portion, for example, a power distributor 15 including a T-junction 15a and an E-vent 15b and a coupling slot 15c for connecting them is used as shown in FIG. Is possible. By using such a power distributor 15, the deterioration of the antenna beam can be further suppressed.

  In FIG. 1 and FIG. 2, the first waveguide connection unit 11a and the second waveguide connection unit 11b are arranged and formed in two rows as viewed from the external space side. May be arranged in a row so as to overlap when viewed from the external space side.

  Through the above, according to the present embodiment, the plurality of slot antennas 14 are functionally divided into four blocks BL in the short direction of the slot antenna 14, and the plurality of slot antennas 14 in the divided blocks BL are Since the slot distributors 14 are connected by the waveguide distributor 11 so that the long sides of the slot antennas 14 face each other, the slot antenna 14 is arranged in the direction in which the coupling of the electric field components becomes strong in the highly directional stacked two-dimensional slot array antenna 1. It is possible to divide each of them and give a phase delay to each of them, and further, it is possible to bend the antenna beam while preventing deterioration of the antenna beam (increase in side lobe).

[Second Embodiment]
Normally, the antenna device is manufactured so that the outer edge shape of each slot antenna 14 is a square as described in the first embodiment in consideration of symmetry and the like. On the other hand, when the deterioration of the antenna beam pattern is allowed to some extent, the arrangement position of the slot antenna 14 may be changed.

  FIG. 4 shows a layer top view of the stacked two-dimensional slot array antenna 1 according to the second embodiment. FIG. 4A is a top view of the uppermost layer, and FIG. 4B is a top view of a formation layer of the waveguide distributor 11.

  In the present embodiment, among the four blocks BL described in the first embodiment, all the constituent elements corresponding to the outermost two blocks BL (out) are shifted outward and formed. .

  As a result, a certain width is secured between the outer block BL (out) and the inner block BL (in), so that the secured area is used to explain the first embodiment described in the first embodiment. Both the first waveguide connection unit 11a and the second waveguide connection unit 11b are formed in the same layer (the formation layer of the coupling end A).

  Even in the present embodiment, the plurality of slot antennas 14 in the divided block BL are connected by the waveguide distributor 11 so that the long sides of the slot antenna 14 face each other. Therefore, it is possible to suppress the deterioration of the antenna beam pattern.

  Finally, in each of the embodiments, the case where the number of coupling slots 12 coupled to the coupling end A of the waveguide distributor 11 is four has been described as an example, but 4, 8, 16,. Multiple numbers may be used. Further, as long as the deterioration of the antenna beam can be allowed to some extent, the number may be at least two.

DESCRIPTION OF SYMBOLS 1 ... Stack type two-dimensional slot array antenna 11 ... Waveguide distributor 11a ... 1st waveguide connection unit (1st connection means)
11b ... second waveguide connection unit (second connection means)
DESCRIPTION OF SYMBOLS 11c ... Coupling slot 12 ... Coupling slot 13 ... Cavity 14 ... Slot antenna 15 ... Power divider 15a ... T-junction 15b ... E- vent 15c ... Coupling slot 3 ... Rectangular waveguide A ... Waveguide divider 11 coupling ends (distribution end)
B: Connection unit with connecting ends B (out): Outer connection unit B (in): Inner connection unit BL: Block

Claims (1)

In a stacked two-dimensional slot array antenna in which metal layers are stacked and a hollow path for feeding radio waves is formed in each layer,
A plurality of rectangular slot antennas formed in the uppermost layer and arranged two-dimensionally;
A conductor that is formed in a layer lower than the uppermost layer and that spatially connects the ends of the cavity paths corresponding to the slot antennas whose long sides face each other among the plurality of slot antennas in the region divided in the short direction of the slot antenna. A wave tube distributor ;
The waveguide distributor is
A first connecting means for spatially connecting the end portions of the hollow path with a plurality of layers, and spatially connecting the end portions with an upper layer, and the first connecting means with a lower layer. A stacked two-dimensional slot array antenna comprising: a second connection means for spatial connection ;

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