JP2020088613A - Waveguide slot antenna - Google Patents

Abstract

To provide a waveguide slot antenna capable of achieving both of a miniaturization and a radiation characteristic on the basis of an arrangement of a slot.SOLUTION: A waveguide slot antenna comprises: a waveguide structured by a dielectric substrate (10) and a metal member (11, 12, and 13) surrounding them; and one or a plurality of slots (14) arranged along a first direction (X) of the waveguide, and defined by an inner edge of the metal member. The metal member contains a first short circuit wall part (W3) which becomes one short circuit surface orthogonal to a first direction of the waveguide, and one or the plurality of slots includes a first slot (14a) defined by the inner edge contacted to the short circuit wall part. The first slot has a prescribed slot length (L) smaller than approximately 0.5 times of a guide wave length of the waveguide along the first direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a waveguide slot antenna in which one or a plurality of slots are provided in a waveguide configured by using a dielectric substrate.

Conventionally, in wireless communication using high frequency signals in the microwave band and millimeter wave band, multiple slots are formed in the waveguide, and the high frequency signal fed from the power supply unit is propagated to the waveguide to create multiple slots. There is known a waveguide slot antenna that emits electromagnetic waves from the above. In recent years, in view of reduction in size and weight and easiness of processing, a waveguide slot antenna composed of a dielectric substrate and a metal member surrounding the dielectric substrate is also used. In general, a standing wave that periodically repeats is generated in the waveguide according to a fixed wavelength in the waveguide.Therefore, a short-circuit surface is arranged at least at one end in the signal transmission direction of the waveguide, and A structure has been proposed in which the center position of the slot is arranged at a distance of ¼ times or ½ times the guide wavelength from the short-circuited surface (see, for example, Patent Document 1). The waveguide slot antenna having such a structure enables the slot arrangement adapted to the periodicity of the electromagnetic field distribution in the waveguide.

JP, 2008-167246, A

Generally, the electromagnetic field distribution of a waveguide having a rectangular cross section is formed by an electric field having no component in the signal transmission direction and a magnetic field having a component in the signal transmission direction. In this case, the influence of the magnetic field, which has a more complicated distribution than the electric field, becomes stronger in the waveguide. Formed (see, eg, FIG. 2). In the above-mentioned conventional structure, the slot arranged at a distance of 1/2 times the guide wavelength from the short-circuited surface is arranged on the boundary of the adjacent magnetic field distribution, so that the magnetic field is concentrated in the slot. The radiation efficiency of the wave tube slot antenna can be improved. However, in such a slot arrangement, the slot in the vicinity of the short-circuit surface spans the two magnetic field distributions, so that the length of the waveguide in the signal transmission direction is required, and it is difficult to miniaturize the waveguide slot antenna. There are challenges. On the other hand, in the above-described conventional structure, the slot arranged at a distance of ¼ times the guide wavelength from the short-circuited surface can be arranged so as to overlap with one magnetic field distribution. Is possible. However, such a slot arrangement has a problem in that the radiating efficiency of the waveguide slot antenna decreases because the canceling magnetic field components increase due to the symmetry of the magnetic field distribution in the shape of the slot in plan view.

The present invention has been made in order to solve the above problems, and realizes a structure capable of achieving both miniaturization of a waveguide slot antenna and excellent radiation characteristics based on the arrangement of slots.

In order to solve the above problems, a waveguide slot antenna of the present invention includes a waveguide including a dielectric substrate (10) and metal members (11, 12, 13) surrounding the dielectric substrate, A waveguide slot antenna, which is arranged along a first direction (X) which is a signal transmission direction of the waveguide and includes one or a plurality of slots (14) defined by an inner edge of the metal member. The metal member includes a first short-circuit wall portion (W3) which is at least one short-circuit surface of the waveguide orthogonal to the first direction, and the one or more slots are the short-circuited portions. A first slot (14a) defined by the inner edge in contact with a wall, the first slot being less than 1/2 times the guide wavelength (λg) of the waveguide along the first direction. It is characterized by having a predetermined slot length (L).

According to the waveguide slot antenna of the present invention, among the one or a plurality of slots arranged in the waveguide formed of the dielectric substrate and the metal member, the inner edge of the metal member that defines the first slot is Since the slot length is made smaller than 1/2 times the guide wavelength λg along the first direction while being arranged in contact with the first short-circuit wall portion, the waveguide with the position of the first short-circuit wall portion as a base point is provided. The slot placement can be optimized for the periodicity of the magnetic field distribution in the tube. Specifically, it is possible to realize an arrangement in which the first slots can suppress the cancellation of the magnetic field components based on the symmetry in the magnetic field distribution according to the conditions of the position and the slot length of the first slots in plan view. .. This makes it possible to reduce the size of the waveguide slot antenna mainly in the first direction without degrading the radiation characteristics.

One or a plurality of slots of the present invention are a plurality of slots including a first slot, and an interval between adjacent slots of the plurality of slots is the same as the guide wavelength along the first direction or 1/the guide wavelength. It may be set to double. As a result, with respect to the magnetic field distribution having periodicity in the waveguide, two adjacent slots are arranged so as to correspond to the two adjacent magnetic field distributions, or every other two magnetic field distributions are arranged. It is possible to selectively determine whether or not to arrange in correspondence with.

The metal member of the present invention includes a first conductor layer formed on a lower surface of a dielectric substrate, a second conductor layer formed on an upper surface of the dielectric substrate and provided with one or a plurality of slots, a first conductor layer and a first conductor layer. It can be configured by including a pair of side wall portions that are side surfaces on both sides of the waveguide that electrically connect between the two conductor layers and extend in the first direction. Further, the metal member of the present invention is further configured to include a second short-circuit wall portion that is the other short-circuit surface orthogonal to the first direction of the waveguide, and includes the first short-circuit wall portion and the second short-circuit wall portion. The distance to the short-circuit wall portion may correspond to N times (N is an integer of 1 or more) times 1/2 of the guide wavelength along the first direction. With this arrangement, the size of the waveguide in which the pair of short-circuit wall portions is provided in the first direction can be adapted to the magnetic field distribution having the periodicity of 1/2 of the guide wavelength. In the above case, the pair of side wall portions and the first and second short-circuit wall portions can be composed of a plurality of via conductors respectively connecting the first conductor layer and the second conductor layer.

In the present invention, when the first and second short-circuit wall portions are provided, one or a plurality of slots is one slot having only the first slot, and the first short-circuit wall portion and the second short-circuit wall portion are provided. The distance may be set to 1/2 times the in-tube wavelength along the first direction. As a result, the size of the waveguide slot antenna in the X direction can be minimized on the assumption that only one slot is provided.

One or a plurality of slots of the present invention are provided between a pair of side wall portions in a third direction orthogonal to the first and second directions in a plan view seen from a second direction perpendicular to the second conductor layer. Can be arranged at a position deviated from the center position of. That is, since the clockwise magnetic field distribution and the counterclockwise magnetic field distribution are alternately arranged along the first direction due to the periodicity of the magnetic field distribution in the waveguide, the spacing between adjacent slots along the first direction is Is equal to the guide wavelength, each slot is arranged at the same position in the third direction, and when the interval between the adjacent slots along the first direction is 1/2 the guide wavelength, each slot is Are arranged in symmetrical positions with respect to the third direction with the center position between the pair of side walls in the third direction being sandwiched therebetween, the magnetic field directions in the respective slots can be aligned.

The present invention may be configured to further include a power feeding portion that penetrates at least between the upper surface and the lower surface of the dielectric substrate and feeds an input signal to the waveguide. In this case, in the second conductor layer, When viewed in a plan view from a vertical second direction, the power feeding unit is arranged at a position overlapping the first slot, and the power feeding unit is arranged along the first direction so as not to deviate from the slot length range. It By providing the power feeding unit integrally arranged with the first slot in this way, it is not necessary to extend the size of the power feeding unit along the first direction, and is suitable for downsizing of the waveguide slot antenna. ing. Further, since the power feeding portion and the first slot act as an integrated antenna and the capacitance between the power feeding portion and the second conductor layer is reduced, good characteristics can be maintained.

According to the present invention, by arranging the first slot in contact with the first short-circuit wall portion, and setting the appropriate slot length so that the shape of the first slot overlaps within the range of one magnetic field distribution immediately below. It is possible to reduce the length mainly along the first direction while adapting to the periodicity of the magnetic field distribution, and to suppress the cancellation of the magnetic field components included in the magnetic field distribution directly below the shape of the first slot. it can. Therefore, it is possible to achieve both miniaturization of the waveguide slot antenna and good radiation characteristics, which were difficult with the conventional structure.

It is a figure which shows the structure of the waveguide slot antenna which concerns on one Example to which this invention is applied, FIG.1(A) is a top view which looked at the waveguide slot antenna from the upper part, FIG.1(B) is It is sectional drawing in the AA cross section of the waveguide slot antenna of FIG. 1(A). 1A is a diagram schematically showing a state in which a magnetic field distribution 20 generated in the waveguide is superimposed on the waveguide and the slots 14a and 14b made of the dielectric substrate 10, corresponding to the top view of FIG. .. It is a figure which shows the structure of the 1st comparative example for demonstrating the effect of this invention, FIG. 3(A) is a top view corresponding to FIG. 1(A), FIG. 3(B) is FIG. It is sectional drawing corresponding to B). FIG. 5 is a diagram showing a structure of a second comparative example for explaining the effect of the present invention, FIG. 4(A) is a top view corresponding to FIG. 1(A), and FIG. 4(B) is FIG. It is sectional drawing corresponding to B). FIG. 3 is a diagram schematically showing a state in which a magnetic field distribution 20 similar to that in FIG. 2 is superimposed, corresponding to the top view of FIG. 3A of the first comparative example. FIG. 6 is a diagram schematically showing a state in which a magnetic field distribution 20 similar to that in FIG. 2 is superimposed, corresponding to the top view of FIG. 4A of the second comparative example. FIG. 7 is a diagram showing a first modification of the waveguide slot antenna to which the present invention is applied, in which the number of slots 14 is changed, and FIG. 7(A) is a top view corresponding to FIG. 1(A). 7B is a cross-sectional view corresponding to FIG. 8 is a diagram showing a second modification of the waveguide slot antenna to which the present invention is applied, in which a feeding portion 15 is provided, and FIG. 8(A) is a top view corresponding to FIG. 1(A). FIG. 1B is a sectional view corresponding to FIG. It is a figure explaining the outline of the manufacturing method of the waveguide slot antenna of this embodiment.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below is an example of a form to which the technical idea of the present invention is applied, and the present invention is not limited by the contents of the present embodiment.

First, the structure of a waveguide slot antenna according to an embodiment of the present invention will be described with reference to FIG. 1A is a top view of the waveguide slot antenna according to the present embodiment as seen from above, and FIG. 1B is a cross-sectional view taken along the line AA of the waveguide slot antenna of FIG. 1A. Is. In FIG. 1, for convenience of description, an X direction (first direction of the present invention), a Y direction (third direction of the present invention), a Z direction (second direction of the present invention) which are orthogonal to each other. ) Are indicated by arrows.

The waveguide slot antenna of the present embodiment includes a dielectric substrate 10 made of a dielectric material such as ceramic, and a conductor layer 11 made of a conductive material formed on the lower surface of the dielectric substrate 10 (the first conductor layer of the present invention). ), a conductor layer 12 (second conductor layer of the present invention) made of a conductive material formed on the upper surface of the dielectric substrate 10, and a plurality of via conductors 13 connecting the upper and lower conductor layers 11 and 12. A plurality of slots 14 (14a, 14b) formed in the conductor layer 12 on the upper surface are provided. Note that FIG. 1A shows a state in which the plurality of via conductors 13 are seen through from the conductor layer 12 side.

The dielectric substrate 10 has a rectangular parallelepiped outer shape whose longitudinal direction is the X direction, and is generally formed by laminating a plurality of dielectric layers. Of the periphery of the dielectric substrate 10, the upper and lower sides (both sides in the Z direction) are covered with the pair of conductor layers 11 and 12 described above, and are covered along the four side surfaces (each side in the X direction and the Y direction). A plurality of via conductors 13 are arranged. With such a structure, the dielectric substrate 10 functions as a waveguide surrounded by the metal member including the pair of conductor layers 11 and 12 and the plurality of via conductors 13. The waveguide has a rectangular cross section (YZ cross section) having a height a in the Z direction and a width b in the Y direction, as shown in FIGS. 1A and 1B, with the X direction as the signal transmission direction. There is. Generally, the relationship of b≈2a is set, but with such a setting, it is possible to propagate TE10 having the upper and lower surfaces of the waveguide as the H surface as the main mode.

The plurality of via conductors 13 are a plurality of columnar conductors in each of which a plurality of through holes penetrating the dielectric substrate 10 are filled with a conductive material, and the distance between adjacent via conductors 13 is half or less of the cutoff wavelength of the waveguide. Is set. Each of the plurality of via conductors 13 has a lower end connected to the conductor layer 11 and an upper end connected to the conductor layer 12, and the side surface of the columnar conductor is covered with the dielectric substrate 10 without being exposed to the outside. As shown in FIG. 1A, the plurality of via conductors 13 has a pair of side wall portions W1 and W2 extending in two rows in the X direction and two rows in the Y direction when viewed in a plan view from the Z direction. Is divided into a pair of short-circuit walls W3 and W4. In the waveguide formed of the dielectric substrate 10, the pair of side wall portions W1 and W2 form side surfaces on both sides of the XZ plane, and the pair of short-circuit wall portions W3 and W4 are arranged in the X direction which is the signal transmission direction. Construct a short circuit plane in the vertical YZ plane. The distance between the short-circuit walls W3 and W4 facing each other in the X direction is set to, for example, twice the guide wavelength λg (2λg).

The pair of side wall portions W1 and W2 and the pair of short-circuit wall portions W3 and W4 are not limited to the case of using the plurality of via conductors 13 shown in FIG. Alternatively, a solid conductor wall surrounding the four sides of the dielectric substrate 10 may be used. In addition, the present invention can be applied to a structure in which only one short-circuit wall W3 is provided and the other short-circuit wall W4 is omitted. For example, another waveguide or device may be connected to the open end of the waveguide slot antenna.

The plurality of slots 14 are arranged in the conductor layer 12 along the X direction. In this embodiment, two slots 14a and 14b are provided in order from the right side of FIG. Each of the two slots 14a and 14b has a rectangular shape having a predetermined slot length L in the X direction and a predetermined width in the Y direction when seen in a plan view from the Z direction. As can be seen from FIG. 1(B), in the conductor layer 12, the two slots 14a and 14b are opened, and the lower dielectric substrate 10 is partially exposed. In other words, the respective shapes of the two slots 14a and 14b are defined by the inner edges of the metal member (the conductor layer 12 and the short-circuit wall W3). The two slots 14a and 14b are arranged so that the distance between the center positions of the waveguides is λg along the X direction with respect to the guide wavelength λg of the waveguide. Further, the two slots 14a and 14b are arranged at positions deviated from the center position of the waveguide in the Y direction.

Here, focusing on the slot 14a on the right side (the first slot of the present invention), one short side of the rectangle of the slot 14a is in contact with the short-circuit wall W3 in a plan view seen from the Z direction. In other words, the shape of the slot 14a is partly defined by the aforementioned inner edge of the short-circuit wall W3. The slot length L of the slot 14a needs to satisfy L<λg/2 along the X direction for the guide wavelength λg. The other dimension parameters of the slots 14a and 14b are appropriately set according to the electromagnetic field distribution in the waveguide. In this embodiment, the effect of the arrangement of the one or more slots 14 will be described in detail later.

Next, the relationship between the arrangement of the slots 14a and 14b in the present embodiment and the magnetic field distribution in the waveguide will be described. 2 corresponds to the top view of FIG. 1(A) and is guided to a waveguide and slots 14a and 14b surrounded by a pair of side wall portions W1 and W2 and a pair of short-circuit wall portions W3 and W4. It is a figure which shows typically the state where the magnetic field distribution 20 generate|occur|produced in a wave tube was piled up. As described above, the distance between the short-circuit walls W3 and W4 in the X direction is 2λg with respect to the guide wavelength λg, and the periodicity of the electromagnetic field distribution in the waveguide is an integral multiple of λg/2. Therefore, four magnetic field distributions 20 (20a, 20b, 20c, 20d) are arranged along the X direction of the waveguide. Since the direction of the electric field is the Z direction, each magnetic field distribution 20 is composed of components in the X direction or the Y direction orthogonal to the electric field. The magnetic field distribution 20 is more complicated than the electric field distribution, and has a strong influence on the radiation characteristics depending on the arrangement of the slots 14. The position of the zero point of the electric field that appears every λg/2, including the positions of the short-circuit walls W3 and W4, becomes the boundary of the magnetic field distribution 20, and the position of the peak of the electric field becomes the center of each magnetic field distribution 20. Then, as indicated by arrows in each magnetic field distribution 20, it can be seen that clockwise magnetic field distributions 20a and 20c and counterclockwise magnetic field distributions 20b and 20d are alternately arranged corresponding to the periodicity of the electric field direction.

In FIG. 2, the slot 14a in contact with the right short-circuit wall W3 is arranged within the range of the magnetic field distribution 20a. Within the rectangular shape of the slot 14a, there are a magnetic field component m1 along the X direction and a magnetic field component m2 along the Y direction in the magnetic field distribution 20a, and others along each direction between these magnetic field components m1 and m2. There is also a magnetic field component of. On the other hand, the slot 14b at a position separated from the slot 14a by the distance λg in the X direction is arranged within the range of the magnetic field distribution 20c sandwiching the magnetic field distribution 20b. Within the rectangular shape of the slot 14b, there are magnetic field components m1 and m2 (not shown) and other magnetic field components of the magnetic field distribution 20c that have the same directionality as the case of the slot 14a. The effects based on the arrangement of the slots 14a and 14b of the present embodiment will be described below in comparison with the conventional structure.

3A and 3B show a structure of a first comparative example for explaining the effect of the present invention, FIG. 3A is a top view corresponding to FIG. 1A, and FIG. It is sectional drawing corresponding to FIG. 1(B). In the first comparative example, the slot 14a on the right side is not in contact with the short-circuit wall portion W3, and the distance from the short-circuit wall portion W3 to the center position of the slot 14a is set to λg/2 along the X direction. There is. On the other hand, FIG. 4 shows a structure of a second comparative example for explaining the effect of the present invention, FIG. 4(A) is a top view corresponding to FIG. 1(A), and FIG. ) Is a cross-sectional view corresponding to FIG. In the second comparative example, the right slot 14a is not in contact with the short-circuit wall W3, and the distance from the short-circuit wall W3 to the center position of the slot 14a is set to λg/4 along the X direction. There is. In both the first and second comparative examples, the distance between the center positions of the two slots 14a and 14b along the X direction is set to λg, as in the present embodiment. 3 and 4, the structure other than the arrangement of the two slots 14a and 14b is the same as that in FIG. 1, and the description thereof will be omitted.

FIG. 5 is a diagram schematically showing a state in which magnetic field distributions similar to those in FIG. 2 are overlapped, corresponding to the top view of FIG. 3A of the first comparative example. The right slot 14a is located at the boundary between the two magnetic field distributions 20a and 20b at the center position, and the left slot 14b is located at the boundary between the two magnetic field distributions 20c and 20d at the center position. On the other hand, in each of the shapes of the two slots 14a and 14b, a magnetic field m3 having the same direction mainly exists along the Y direction. Therefore, the directions of the magnetic field components m3 are aligned within the shapes of the slots 14a and 14b, so that the radiation efficiency is increased.

However, in the first comparative example, one slot 14 always extends over two adjacent magnetic field distributions 20, so that the range of the four magnetic field distributions 20 corresponding to the two slots 14a and 14b is along the X direction. Therefore, a length of 2λg is required. On the other hand, according to the present embodiment, since each of the slots 14a and 14b is within the range of one magnetic field distribution 20, as shown in FIG. 2, at least 3 slots 14a and 14b are provided. Only one magnetic field distribution 20 (20a, 20b, 20c) is required, and the waveguide slot antenna can be reduced to a length of 1.5λg along the X direction. Assuming a structure in which only one slot 14a is provided in the waveguide slot antenna as described later, the first comparative example requires a length λg in the X direction corresponding to two magnetic field distributions 20. On the other hand, the present embodiment can reduce the length in the X direction to λg/2 corresponding to one magnetic field distribution 20, and halve the length in the X direction as compared with the first comparative example. You can

FIG. 6 is a diagram schematically showing a state in which a magnetic field distribution 20 similar to that in FIG. 2 is overlapped, corresponding to the top view of FIG. 4A of the second comparative example. The slot 14a on the right side is arranged within the range of the magnetic field distribution 20a, and the slot 14b on the left side is arranged within the range of the magnetic field distribution 20c. On the other hand, in the rectangular shape of each of the two slots 14a and 14b, the magnetic field component m1 along the X direction, the magnetic field components m2 and m3 in the opposite directions along the Y direction, and the magnetic field components m1 and There are also other magnetic field components in each direction between m2 and m3. According to the structure of the second comparative example, since one slot 14 is within the range of one magnetic field distribution 20, for example, when two or one slot 14 is provided in the waveguide slot antenna, X The length in the direction can be reduced to the same extent as this embodiment, and is suitable for downsizing.

However, in the second comparative example, there are magnetic field components m2 and m3 in the opposite directions along the Y direction in the respective shapes of the slots 14a and 14b, and these magnetic field components m2 and m3 cancel each other out. Therefore, the radiation level from each slot 14 is inevitably reduced. On the other hand, according to the present embodiment, the magnetic field components m1 and m2 existing in the shape of one slot 14 do not cancel each other out, so that the radiation level becomes higher than that in the second comparative example. However, as described above, even if the condition of the slot length L<λg/2 in the present embodiment is satisfied, when the slot length L approaches λg/2, the canceling magnetic field components increase, so the slot length L is It is desirable to set it to about 30 to 45% of λg.

As described above, in the first comparative example, it is difficult to miniaturize the waveguide slot antenna, and in the second comparative example, the reduction of the radiation efficiency of the slot 14 cannot be avoided. It is difficult to achieve both miniaturization and improvement of radiation efficiency. On the other hand, in the structure of the present embodiment, by adopting the arrangement in which one end of the slot 14a is in contact with the short-circuit wall W3, it is possible to achieve both miniaturization of the waveguide slot antenna and improvement of radiation efficiency. Become.

The waveguide slot antenna to which the present invention is applied is not limited to the structure shown in FIG. 1, and various modifications are possible on the assumption that the effects of the present invention are exhibited. FIG. 7 shows a first modification in which the number of slots 14 is changed, FIG. 7(A) is a top view corresponding to FIG. 1(A), and FIG. 7(B) is shown in FIG. 3 is a sectional view corresponding to FIG. In the first modification, as described above, only one slot 14a is arranged in the conductor layer 12. The arrangement of the slots 14a in FIG. 7A is the same as that in FIG. 1A, but one slot 14a overlaps only one magnetic field distribution 20a as shown in FIG. Since the size may be set to the length λg/2 of one magnetic field distribution 20a in the X direction, the structure is most suitable for downsizing.

The number of slots 14 of the waveguide slot antenna is not limited to one or two as long as the effects of the present invention can be obtained. For example, the present invention can be applied even when a large number of slots 14 of three or more are arranged. In this case, for the guide wavelength λg, the interval along the X direction between the adjacent slots 14 may be set to λg according to the arrangement similar to that of FIG. The interval may be shortened and set to λg/2. When the plurality of slots 14 are arranged at intervals of λg/2, the clockwise and counterclockwise rotations of the magnetic field distribution 20 are alternately arranged, so that the adjacent slots 14 are located symmetrically with respect to the center position in the Y direction. By arranging them, the directions of the magnetic field components in all the shapes of the slots 14 can be made uniform.

FIG. 8 shows a second modification in which the waveguide slot antenna shown in FIG. 1 is provided with a power feeding unit 15 for feeding an input signal, and FIG. 8A corresponds to FIG. 8B is a cross-sectional view (cross-section taken along line BB in FIG. 8A) corresponding to FIG. 1B. Generally, the power feeding unit arranged at a position away from the two slots is provided in a plan view seen from the Z direction, but the power feeding unit 15 of the second modification is arranged at a position overlapping with one slot 14a. ing. In this case, the region where the power feeding unit 15 and the slot 14a overlap has a shape in which a part of the long side of the rectangular basic shape of the slot 14a projects in a semicircular shape. Further, the distance along the X direction between the center position of the power feeding unit 15 and the right short-circuit wall W3 is set to 1/4 times the guide wavelength of the waveguide. Further, the power feeding portion 15 is formed so as to penetrate between the upper surface and the lower surface of the dielectric substrate 10.

As shown in FIG. 8(B), the power feeding portion 15 includes a power feeding terminal 15a arranged in the same plane as the conductor layer 11 on the lower surface and an upper end portion 15b arranged in the same plane as the conductor layer 12 on the upper surface. , A power supply via conductor 15c for electrically connecting the power supply terminal 15a and the upper end portion 15b. The power supply terminal 15a and the upper end portion 15b are formed of the same conductive material as the conductor layers 11 and 12, but are not in contact with the conductor layers 11 and 12. Therefore, in a plan view viewed from the Z direction, a ring-shaped punching pattern (not shown) is formed around the power supply terminal 15a, and similarly, a ring-shaped punching pattern is also formed around the upper end portion 15b. .. The power feeding via conductor 15c is formed in a cylindrical shape, and the impedance matching of the power feeding portion 15 can be optimized mainly according to the diameter of the power feeding via conductor 15c.

According to the second modified example, since the power feeding unit 15 is arranged at the position overlapping the slot 14a, an extra size in the X direction of the waveguide due to the arrangement of the power feeding unit 15 is unnecessary, and thus the power feeding unit 15 is provided. Even if there is, the waveguide slot antenna can be downsized. Further, from the viewpoint of antenna characteristics, the slot 14a and the upper end portion 15b of the power feeding portion 15 act as one antenna having an integral shape, and suppress mutual interference between the slot 14a and the power feeding portion 15. it can. Further, since the upper end portion 15b of the power feeding portion 15 is in the same plane as the conductor layer 12, the capacitance between the upper end portion 15b and the conductor layer 12 is mainly reduced, and thus the capacitance component of the power feeding portion 15 is increased. It is possible to prevent deterioration of high frequency characteristics. Furthermore, according to the second modified example, the feeding portion 15 does not deviate from the range of the slot length L of the slot 14a along the X direction. Therefore, by arranging the feeding portion 15, the waveguide slot depending on the slot length L is arranged. It is possible to avoid that the resonance frequency of the antenna is affected. As described above, the second modification can obtain the effect of downsizing while maintaining the good characteristics of the waveguide slot antenna provided with the power feeding portion 15.

In addition, the range of the slot length L of the slot 14a in the second modification means a region sandwiched by a pair of long sides extending along the X direction that defines the rectangular slot 14a. Further, when the shape of the slot 14a is a substantially rectangular shape having a curved or linear chamfered portion at the corner of a rectangle having a long side in the X direction, the range of the slot length L of the slot 14a is in the X direction. It means a region sandwiched by a pair of long sides extending along, but the chamfered portion is not included in the pair of long sides.

Next, an outline of a method for manufacturing the waveguide slot antenna of this embodiment will be described with reference to FIG. Here, a case of manufacturing a waveguide slot antenna having a cross-sectional structure corresponding to FIG. 1B will be described as an example. First, as a plurality of dielectric layers forming the dielectric substrate 10, for example, a plurality of ceramic green sheets 30 for low-temperature firing formed by a doctor blade method are prepared. Then, as shown in FIG. 9A, a punching process is performed at a predetermined position of each ceramic green sheet 30 to open a plurality of via holes 31. The position and the number of each via hole 31 in each ceramic green sheet 30 are set in correspondence with the arrangement of the plurality of via conductors 13 that form a pair of side surfaces and a pair of short-circuit surfaces of the waveguide.

Next, as shown in FIG. 9B, a plurality of via holes 31 formed in the respective ceramic green sheets 30 are filled with a conductive paste containing Cu by screen printing to obtain a plurality of via conductors. 13 is formed. Subsequently, as shown in FIG. 9C, the conductive layer 11 is formed by applying a conductive paste containing Cu to the lower surface of the lowermost ceramic green sheet 30 by screen printing. Similarly, a conductive paste containing Cu is applied to the upper surface of the uppermost ceramic green sheet 30 by screen printing to form the conductor layers 12 having the two slots 14a and 14b, respectively.

Then, a plurality of ceramic green sheets 30 are laminated in order and then heated and pressed to form a laminated body. After that, the obtained laminated body is degreased and fired to complete the waveguide slot antenna formed on the dielectric substrate 10, as already described with reference to FIG.

Although the content of the present invention has been specifically described based on the present embodiment, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof. For example, the structure example of FIG. 1 of the present embodiment is an example, and the present invention is widely applied to various waveguide slot antennas using other structures and materials as long as the effects of the present invention can be obtained. Can be applied. Further, in other respects, the content of the present invention is not limited by the above-described embodiment, and the content disclosed in the above-mentioned embodiment is appropriately changed without being limited as long as the effect of the present invention can be obtained. It is possible.

In the present embodiment, the structure in which one or a plurality of slots 14 includes one slot 14a that is in contact with one short-circuit wall portion W3 along the X direction has been described. A structure may be provided that includes one slot 14 that contacts one short-circuit wall W3 and one slot 14 that contacts the other short-circuit wall W4. In this case, it is necessary to ensure the symmetry of each magnetic field distribution that overlaps each slot 14.

10... Dielectric substrate 11, 12... Conductor layer 13... Via conductor 14... Slot 15... Feeding part 20... Magnetic field distribution 30... Ceramic green sheet 31... Via holes W1, W2... Side wall part W3, W4... Short-circuit wall part

Claims (8)

A waveguide including a dielectric substrate and a metal member surrounding the dielectric substrate, the waveguide is arranged along a first direction that is a signal transmission direction of the waveguide, and is defined by an inner edge of the metal member. A waveguide slot antenna comprising one or a plurality of slots,
The metal member includes a first short-circuit wall portion serving as at least one short-circuit surface orthogonal to the first direction of the waveguide,
The one or more slots include a first slot defined by the inner edge in contact with the shorting wall,
The first slot has a predetermined slot length that is smaller than ½ times the guide wavelength of the waveguide along the first direction.
A waveguide slot antenna characterized by the above. The one or more slots are a plurality of slots including the first slot, and an interval between adjacent slots of the plurality of slots is the same as the guide wavelength along the first direction or of the guide wavelength. The waveguide slot antenna according to claim 1, wherein the number is 1/2. The metal member is
A first conductor layer formed on the lower surface of the dielectric substrate;
A second conductor layer formed on the upper surface of the dielectric substrate and provided with the one or more slots;
A pair of side wall portions that electrically connect between the first conductor layer and the second conductor layer and that are side surfaces on both sides of the waveguide extending in the first direction;
The waveguide slot antenna according to claim 1 or 2, wherein the waveguide slot antenna is configured to include. Further, the metal member includes a second short-circuit wall portion which is the other short-circuit surface of the waveguide orthogonal to the first direction, and the first short-circuit wall portion and the second short-circuit wall portion. 4. The waveguide slot according to claim 3, wherein a distance between and is equal to N (N is an integer greater than or equal to 1) times 1/2 of the guide wavelength along the first direction. antenna. The pair of side wall portions and the first and second short-circuit wall portions are composed of a plurality of via conductors respectively connecting the first conductor layer and the second conductor layer. 4. The waveguide slot antenna according to item 4. The one or more slots include only the first slot, and a distance between the first short-circuit wall portion and the second short-circuit wall portion is 1/one of the guide wavelength along the first direction. The waveguide slot antenna according to claim 4 or 5, wherein the waveguide slot antenna corresponds to twice the number. The one or the plurality of slots are in a pair of side wall portions in a third direction orthogonal to the first and second directions when seen in a plan view seen from a second direction perpendicular to the second conductor layer. The waveguide slot antenna according to any one of claims 3 to 6, wherein the waveguide slot antenna is arranged at a position deviated from a center position therebetween. At least a power feeding portion that is formed to penetrate between the upper surface and the lower surface of the dielectric substrate and feeds an input signal to the waveguide,
In a plan view seen from a second direction perpendicular to the second conductor layer, the power feeding section is arranged at a position overlapping the first slot, and the power feeding section is arranged along the first direction in the slot. 8. The waveguide slot antenna according to claim 3, wherein the waveguide slot antenna does not deviate from the range of length.

Images