JP2017060087A - Waveguide tube slot antenna and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waveguide tube slot antenna capable of stably exhibiting desired antenna characteristics at low costs.SOLUTION: There is provided a waveguide tube slot antenna 1 which has radiation slots 3 provided on a waveguide tube 10 that has a waveguide 2 extending in a tube axis direction, in a tube axis direction at predetermined intervals, where the waveguide tube 10 is formed of a combination body of first and second waveguide formation members 11, 12, each having a cross-section with ends in each portion in an extension direction of the waveguide 2. The first waveguide formation member 11 is formed of a flat metal member having the radiation slots 3, the second waveguide formation member 12 is formed of a resin member integrally holding the first waveguide formation member 11, and at least a defined surface of the waveguide 2 is covered with a continuous conductive coating film 6 having no cut line.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a waveguide slot antenna and a manufacturing method thereof.

  As is well known, a waveguide slot antenna is used in various electric / electronic devices (systems) having a wireless communication function. It is used as an antenna for transmitting and receiving centimeter wave radio waves). Millimeter-wave radio waves are used in, for example, in-vehicle radar systems, and centimeter-wave radio waves are used in satellite broadcasting systems such as broadcasting satellites (BS) and communication satellites (CS), wireless LANs, and Bluetooth (registered trademark). ) And other data transmission systems, electronic fee collection systems (ETC (registered trademark)), and the like. The millimeter wave band radio wave is a radio wave having a wavelength of 1 to 10 mm and a frequency of 30 to 300 GHz, and the centimeter wave band radio wave is a radio wave having a wavelength of 10 to 100 mm and a frequency of 3 to 30 GHz.

  Various waveguide slot antennas have been proposed. In order to reduce the cost of the waveguide slot antenna, the present applicant has disclosed a resin-made waveguide slot antenna in Patent Document 1 below. is suggesting. More specifically, a resin-made waveguide having a waveguide extending in the tube axis direction, the defined surface of the waveguide being covered with a conductive film, and along the tube axis direction of the waveguide. And a plurality of radiating slots provided at predetermined intervals, and the waveguide includes first and second waveguide forming members each having a cross section (cross section orthogonal to the tube axis direction) having an end shape. It is a waveguide slot antenna composed of a coupled body.

JP 2014-60700 A

By the way, the antenna size (especially the dimension in the tube axis direction) of the waveguide slot antenna is determined mainly according to the frequency of radio waves to be transmitted and received, and the antenna size decreases as the corresponding frequency increases. For this reason, the smaller the antenna size, the thinner the wall of the waveguide must be. However, in this case, undesired deformation (warping or bending) is likely to occur in the waveguide with a temperature change or the like. And when the above deformation occurs,
・ The shape accuracy of the waveguide is adversely affected and the propagation efficiency of radio waves is reduced.
-A gap is generated at the contact portion of both waveguide forming members, and radio waves propagating through the waveguide through this gap are likely to leak to the outside.
Such a problem that the antenna characteristics are deteriorated easily occurs.

  In view of the above circumstances, an object of the present invention is to provide a waveguide slot antenna that can be manufactured at low cost and can stably exhibit desired antenna characteristics.

  The present invention created to achieve the above object includes a waveguide having a waveguide extending in the tube axis direction and a plurality of radiation slots provided at predetermined intervals along the tube axis direction of the waveguide. And a waveguide slot antenna comprising a combination of first and second waveguide forming members whose cross sections in the respective extending directions of the waveguide are end-shaped. The first waveguide forming member is composed of a flat metal member having a plurality of radiation slots, and the second waveguide forming member is integrated with the first waveguide forming member. It is composed of a held resin member, and at least a defined surface of the waveguide of the waveguide is covered with a continuous conductive film.

  The waveguide slot antenna having the above configuration inserts a first waveguide forming member made of a flat metal member having a plurality of radiation slots, and injection-molds the second waveguide forming member with a resin. Thus, a waveguide can be obtained, and thereafter, this waveguide can be manufactured by performing a process of forming a conductive film covering at least the defined surface of the waveguide.

  As described above, the first waveguide forming member made of a flat metal member is inserted, and the second waveguide forming member is injection-molded with resin to obtain a waveguide. For example, since the first waveguide forming member can function as a reinforcing member, the second waveguide forming member can be deformed (particularly, warped or bent in the direction along the tube axis direction) due to molding shrinkage. While preventing as much as possible, it is possible to obtain a waveguide that is unlikely to be deformed due to a temperature change or the like at low cost. The second waveguide forming member integrally holds the first waveguide forming member, and at least one of the waveguides composed of a combination of the two waveguide forming members. Since the defined surface of the waveguide is covered with a continuous conductive film (continuous conductive film), the radio wave propagating through the waveguide leaks to the outside at the coupling portion of both waveguide forming members. It is possible to effectively prevent formation of a gap. From the above, it is possible to realize a waveguide slot antenna that can be manufactured at low cost and can stably exhibit desired antenna characteristics.

  In the above configuration, the first waveguide forming member is provided on the front side in the radiation direction of the radio wave radiated to the outside through the radiation slot, and further includes a hole portion in which the radiation slot is disposed on the inner periphery. be able to. By providing such a hole, unnecessary radiation, also called a grating lobe, can be eliminated, so that the antenna characteristics of the waveguide slot antenna can be improved.

  In this case, the first waveguide forming member can be composed of a laminate of a first metal plate having a radiation slot and a second metal plate having the hole. If it does in this way, let each of the 1st metal plate which has a radiation slot, and the 2nd metal plate which has the above-mentioned hole be a press-molded article obtained by giving press processing (punching processing) to a metal plate. Therefore, the first waveguide forming member having the radiation slot and the hole can be manufactured at a low cost.

  The conductive coating can also be formed continuously along the outer surface of the waveguide. Such a conductive film (waveguide) can be obtained by subjecting the waveguide to a conductive film formation process without performing a masking process. In this way, the masking forming process for the waveguide can be omitted, which is advantageous in reducing the cost of the waveguide slot antenna.

  As described above, according to the present invention, it is possible to realize a waveguide slot antenna that can be produced at low cost and can stably exhibit desired antenna characteristics.

(A) The figure is a partial schematic plan view of the waveguide slot antenna according to the first embodiment of the present invention, (b) is a transverse sectional view of the antenna, and (c) is a longitudinal section of the antenna. FIG. (A) is a partially enlarged sectional view of the waveguide slot antenna shown in FIG. 1, and (b) is a partially enlarged sectional view of a waveguide slot antenna according to a modification. (A) is a transverse sectional view of a waveguide slot antenna according to a second embodiment of the present invention, and (b) is a longitudinal sectional view of the antenna. (A) is a partial schematic plan view of a waveguide slot antenna according to a third embodiment of the present invention, (b) is a transverse sectional view of the antenna, and (c) is a longitudinal section of the antenna. FIG. FIG. 6 is a cross-sectional view of a waveguide slot antenna according to a fourth embodiment of the present invention, which is a modification of FIG. 1.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1A to 1C are a partial plan view and a transverse cross-sectional view of a waveguide slot antenna 1 according to the first embodiment of the present invention [a cross-sectional view taken along line XX in FIG. ] And longitudinal cross-sectional view [cross-sectional view in the YY line of Fig.1 (a)]. A waveguide slot antenna 1 shown in FIG. 1 is used as a member constituting an antenna unit for transmitting and receiving millimeter wave radio waves, for example. Although not shown, the antenna unit includes a plurality of (for example, five) waveguide slot antennas 1 connected in parallel, and a power supply that supplies high-frequency power (radio waves) to each waveguide slot antenna 1. It consists of a waveguide. In this case, of the five waveguide slot antennas 1, for example, the antenna 1 disposed at the center can function as a radio wave transmitting antenna, and two antennas 1 disposed on both sides of the antenna 1 can function as radio waves. It can function as a receiving antenna. When the antenna unit 1 is used for transmitting and receiving millimeter wave (for example, 76 GHz band) radio waves, the size of the waveguide slot antenna 1 is, for example, in the tube axis direction (up and down direction in FIG. 1). Dimension: 90 mm, dimension in the width direction (left and right direction in FIG. 1A): 7 mm, dimension in the height direction (direction perpendicular to the sheet surface in FIG. 1A): 7 mm.

  Next, the detailed structure of the waveguide slot antenna 1 will be described. As shown in FIGS. 1A to 1C, the waveguide slot antenna 1 includes a waveguide 10 having a waveguide 2 extending in the tube axis direction and a tube axis direction of the waveguide 10. A plurality of radiating slots 3 provided at predetermined intervals along the waveguide 10 and a feeding slot 5 provided at one end of the waveguide 10 in the tube axis direction for supplying high-frequency power (radio waves) to the waveguide 2. As shown in FIG. 1A, the radiation slot 3 of the present embodiment is provided such that a straight line extending through the center in the width direction is inclined by 45 ° with respect to the tube axis direction. The inclination angle of the radiating slot 3 with respect to can be set as appropriate according to the application.

  As shown in FIGS. 1B and 1C, the waveguide 10 is a rectangular waveguide having a rectangular cross section at each portion in the extending direction of the waveguide 2. More specifically, it includes a top wall 10a and a bottom wall 10b that are parallel to each other, side walls 10c and 10d that are parallel to each other, and end walls 10e and 10f that close one end and the other end opening in the tube axis direction. . The plurality of radiation slots 3 are provided on the top wall 10a, and the power supply slot 5 is provided on the bottom wall 10b. In the present embodiment, the cross-sectional dimensions of the top wall 10a and the bottom wall 10b are longer than the cross-sectional dimensions of the side walls 10c and 10d. In the following, for convenience of explanation, the side on which the top wall 10a is provided is referred to as the upper side, and the side on which the bottom wall 10b is provided is referred to as the lower side, but the usage mode of the waveguide slot antenna 1 is not limited. .

  The top wall 10a is provided on the front side in the radiation direction of the radio wave radiated to the outside through the radiation slot 3, and has a hole 4 in which the radiation slot 3 is arranged on the inner periphery. That is, the top wall 10 a is provided with a plurality of holes 4 opened on the outer surface (upper surface) along the tube axis direction, and one radiation slot 3 is opened on the inner bottom surface of each hole 4. In the present embodiment, the hole 4 is formed in a perfect circle shape in plan view, but the hole portion 4 may be formed in a rectangular shape, an elliptical shape, or the like in plan view. By providing such a hole 4, unnecessary radiation, also referred to as a grating lobe, is suppressed, so that antenna characteristics can be enhanced.

  The waveguide 10 is composed of a combination of first and second waveguide forming members 11 and 12 whose end sections are cross sections in the extending direction of the waveguide 2. Specifically, as shown in FIGS. 1B and 1C, the first waveguide forming member 11 constituting the top wall 10a, the bottom wall 10b, the side walls 10c and 10d, and the end walls 10e and 10f are provided. A combined body with the integrally formed second waveguide forming member 12, in other words, the first waveguide forming member 11 having a flat plate shape, and a second guide having a concave shape with the transverse section opened upward. The waveguide 10 is constituted by a combination with the wave tube forming member 12.

  The first waveguide forming member 11 of the present embodiment includes a first metal plate 11A formed into a predetermined shape by pressing (punching) a metal plate, and pressing (punching) the metal plate. ) To form a laminated body with the second metal plate 11B formed in a predetermined shape. The radiating slot 3 is formed simultaneously with the first metal plate 11A obtained by pressing, and the hole 4 is formed simultaneously with the second metal plate 11B obtained by pressing.

  On the other hand, the second waveguide forming member 12 is a resin member integrally holding the first waveguide forming member 11, that is, the first waveguide forming member 11 is inserted and injection molded with resin. The power supply slot 5 is molded at the same time as the injection molding. The resin material used for molding the second waveguide forming member 12 is based on, for example, at least one thermoplastic resin selected from the group of liquid crystal polymer (LCP), polyphenylene sulfide (PPS), and polyacetal (POM). As the resin, a resin added with one or more fillers such as glass fiber (GF) and carbon fiber (CF) is used as necessary. Among the base resins exemplified above, LCP is preferable in that it has excellent shape stability compared to PPS and the like and can suppress the amount of burrs generated during molding.

  As shown in an enlarged view in FIG. 2A, the second waveguide forming member 12 has a holding portion 12a that holds the first waveguide forming member 11 integrally. This holding part 12a is arranged as an insert part in a molding die in a state where both metal plates 11A and 11B are stacked, and then the above resin material is filled in the filling part (hole part) 7 provided in both metal plates 11A and 11B. The second waveguide forming member 12 is obtained by injection molding so as to be filled. In this embodiment, as shown in FIG. 1C, the holding portions 12a are provided only at both ends (terminal walls 10e and 10f) in the tube axis direction, but the holding portions 12a are provided on the side walls 10c and 10d. Of course it is also possible.

  The holding portion 12a is formed by a method other than the above, for example, after the metal plates 11A and 11B are joined and integrated by an appropriate means such as adhesion or welding, and then the integrated product (first waveguide forming member 11). Is inserted into the molding die as an insert part, and then the second waveguide forming member 12 is filled with the resin material in the plurality of filling portions 7 provided only on the first metal plate 11A. It can also be obtained by injection molding [see FIG. 2 (b)]. The configuration shown in FIG. 2B is preferably obtained as described above from the viewpoint of suppressing the deformation of the second waveguide forming member 12 due to molding shrinkage, but only the first metal plate 11A. After the second waveguide forming member 12 is injection-molded with a resin as an insert part, the second metal plate 11B can be bonded to the first metal plate 11A by an appropriate means. is there.

  Of the waveguide 10, at least the definition surface of the waveguide 2 is covered with a conductive film 6 as shown in the enlarged view of FIG. The conductive coating 6 is not interrupted at the contact portion (boundary portion) between the two waveguide forming members 11 and 12, and the surface defining the waveguide 2 of the first waveguide forming member 11, and the first The two waveguide forming members 12 are continuous on the surface defining the waveguide 2. Such a conductive coating 6 is obtained with respect to the waveguide 10 after obtaining the waveguide 10 composed of the combination of the first and second waveguide forming members 11 and 12 as described above. It can be obtained by forming the conductive film 6, specifically, electroless plating. Although not shown, the conductive coating 6 may be formed on the outer surface of the waveguide 10 (the entire surface of the waveguide 10) in addition to the surface defining the waveguide 2. Such a configuration can be obtained by subjecting the waveguide 10 to the formation process of the conductive film 6, specifically, the electroless plating process, without subjecting the waveguide 10 to the masking process. In this case, the masking process for the waveguide 10 can be omitted, which is advantageous in reducing the cost required for forming the conductive film 6 and thus the manufacturing cost of the waveguide slot antenna 1.

  The conductive coating 6 may be composed of a single-layer metal plating coating, but here the first coating 6a deposited on the waveguide 10 and the second deposited on the first coating 6a. The conductive film 6 is composed of the film 6b. The first coating 6a can be a plating coating of metal such as copper, silver, gold, etc. that is particularly excellent in electrical conductivity (propagation of radio waves), and the second coating 6b can be made of a durable (anti-resistance) such as nickel. It is possible to obtain a metal plating film having excellent corrosion resistance. By making the conductive coating 6 have such a laminated structure, high conductivity and high durability can be imparted to the conductive coating 6 at the same time, and the amount of expensive metals such as copper and silver used. It is possible to suppress the increase in cost.

  If the film thickness of the conductive coating 6 is too thin, the durability becomes poor. Conversely, if the film is too thick, it takes a long time to form the coating, resulting in high costs. From this point of view, the thickness of the conductive coating 6 is preferably 0.2 μm or more and 1.5 μm or less. When the conductive coating 6 has a laminated structure of the first coating 6a and the second coating 6b as in the present embodiment, the film thickness of the first coating 6a and the second coating 6b is, for example, 0.1. It can be about -1.0 micrometer and about 0.1-0.5 micrometer.

  As described above, the waveguide slot antenna 1 of the present embodiment includes the first waveguide forming member 11 in which the waveguide 10 is a flat metal member having a plurality of radiation slots 3; The first waveguide forming member 11 is composed of a combination of second waveguide forming members 12 made of a resin member integrally holding, and at least the waveguide 2 of the waveguide 10 is defined. The surface is covered with a continuous conductive coating 6. In the waveguide slot antenna 1 having such a configuration, the first waveguide forming member 11 made of a flat metal member is inserted, and the second waveguide forming member 12 is injection-molded with resin. Thus, the waveguide 10 can be obtained, and then the waveguide 10 can be manufactured by performing a process for forming the conductive film 6 that covers at least the defined surface of the waveguide 2.

  As described above, if the first waveguide forming member 11 made of metal is inserted and the second waveguide forming member 12 is injection-molded with resin, the first waveguide 10 is obtained. Since the waveguide forming member 11 can function as a reinforcing member, the second waveguide forming member 12 is prevented from being deformed due to molding shrinkage as much as possible, and deformation due to temperature change or the like occurs. A difficult waveguide 10 can be obtained at low cost.

  Also, the second waveguide forming member 12 is inserted into the first waveguide forming member 11 and injection molded with resin, so that the second waveguide forming member 12 becomes the first waveguide. It has the holding | maintenance part 12a which hold | maintained the formation member 11 integrally, and among the waveguides 10 which consist of the coupling body of both the waveguide formation members 11 and 12, at least the defined surface of the waveguide 2 continued. A gap in which radio waves propagating through the waveguide 2 leak to the outside at the contact portions of the two waveguide forming members 11 and 12 by being covered with the conductive coating (non-cut conductive coating) 6. Can be effectively prevented. As described above, while being able to be manufactured at low cost, the propagation efficiency of radio waves is reduced due to the reduction in the accuracy of the shape of the waveguide 10 (waveguide 2), and the contact between the waveguide forming members 11 and 12 is reduced. Waveguide slot that can stably exhibit desired antenna characteristics by reducing as much as possible the possibility of occurrence of problems such as external leakage of radio waves through gaps generated in the section, which deteriorate antenna characteristics. The antenna 1 can be realized.

  The waveguide slot antenna A according to the first embodiment of the present invention has been described above. However, the waveguide slot antenna A may be appropriately modified without departing from the gist of the present invention. Is possible. Hereinafter, although other embodiments of the present invention will be described with reference to the drawings, the same reference numerals are assigned to the configurations according to the first embodiment described above, and the duplicate description will be omitted.

  3A and 3B conceptually show a transverse sectional view and a longitudinal sectional view of the waveguide slot antenna 1 according to the second embodiment of the present invention. The main difference between the waveguide slot antenna 1 shown in the figure and the waveguide slot antenna 1 according to the first embodiment of the present invention described above is that the first waveguide forming member 11 is integrated. The holding portion 12a is held endlessly along the upper end outer peripheral portion of the second waveguide forming member 12, that is, along the upper end outer peripheral portions of the side walls 10c and 10d and the end walls 10e and 10f. is there. Even when such a configuration is employed, the same effects as those of the waveguide slot antenna 1 according to the first embodiment can be enjoyed.

  4 (a) to 4 (c), a partial plan view and a transverse sectional view of a waveguide slot antenna 1 according to a third embodiment of the present invention [a cross section taken along line XX shown in FIG. FIG.] And a longitudinal sectional view [cross-sectional view taken along line YY shown in FIG. In the waveguide slot antenna 1 of this embodiment, as shown in FIG. 4A, a radiating slot array in which a plurality of radiating slots 3 are arranged at predetermined intervals along the tube axis direction is provided on the waveguide 10. Two rows are provided in the width direction, and the arrangement positions of the radiation slots 3 constituting one radiation slot row and the radiation slots 3 constituting the other radiation slot row are different from each other in the tube axis direction. In brief, in the waveguide slot antenna 1 of this embodiment, a plurality of radiation slots 3 and holes 4 are arranged in a staggered manner.

In addition, the waveguide slot antenna 1 (waveguide 10) of this embodiment is arranged in parallel with the side walls 10c and 10d as shown in FIGS. It further includes a branch wall 10g that branches into the waveguides 2A and 2B, and a plurality of inner walls 13 that reduce the cross-sectional area of the waveguide 2 (2A and 2B) at the position where the radiation slot 3 is formed. The inner wall 13 is erected on the inner bottom surface of the bottom wall 10b. Of the two inner walls 13, 13 adjacent in the tube axis direction, the height dimension of the inner wall 13 on the side relatively close to the power supply slot 5 is h _1. When the height dimension of the inner wall 13 relatively far from the power supply slot 5 is h ₂ , the inner wall 13 is formed so as to satisfy the relational expression h ₁ ≦ h ₂ [enlarged view in FIG. reference]. One radiation slot row is formed along the waveguide 2A, and the other radiation slot row is formed along the waveguide 2B.

As described above, if the inner wall 13 for reducing the cross-sectional area of the waveguide 2 is provided at the position where the radiation slot 3 is formed, the radiation efficiency of the radio wave propagating through the waveguide 2 can be increased. In particular, of the two inner walls 13 and 13 adjacent in the tube axis direction, the height dimension of the inner wall 13 on the side relatively close to the power supply slot 5 is h ₁ , and the inner wall 13 on the side relatively far from the power supply port 5 is. When the height dimension is h ₂ , if the relational expression h ₁ ≦ h ₂ is satisfied, the amount of radio waves radiated to the outside through each radiation slot 3 becomes difficult to vary between the radiation slots 3. It is possible to radiate a substantially equal amount of radio waves from each radiation slot 3. Therefore, it is possible to avoid variations in antenna performance in each part of the tube axis direction as much as possible, and the waveguide slot antenna 1 having excellent reliability can be realized.

  In the waveguide 10 constituting the waveguide slot antenna 1 of this embodiment, the first waveguide forming member 11 made of a flat metal member and the first waveguide forming member 11 are integrally formed. And the second waveguide forming member 11 made of resin (injected and molded by inserting the first waveguide forming member 11), and at least the defining surface of the waveguide 2 is Covered with a continuous conductive coating 6.

  FIG. 5 shows a schematic cross-sectional view of a waveguide slot antenna 1 according to the fourth embodiment of the present invention. A waveguide slot antenna 1 shown in the figure is a modification of the waveguide slot antenna 1 according to the first embodiment of the present invention shown in FIGS. The forming member 11 is not a combination of the first metal plate 11A having the plurality of radiation slots 3 and the second metal plate 11B having the plurality of holes 4, but is formed of a single flat metal member. However, the configuration differs from the waveguide slot antenna 1 shown in FIG. Although not shown, it is of course possible to apply the configuration of the present embodiment to the waveguide slot antenna 1 shown in FIGS.

  In addition to being applied to the waveguide slot antenna 1 for transmitting and receiving millimeter-wave (high-frequency) radio waves, the present invention described above is for transmitting and receiving centimeter-wave (low-frequency) radio waves. Of course, the present invention can also be applied to the waveguide slot antenna.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. The scope of the present invention is defined by the terms of the claims, and includes the equivalent meanings recited in the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1 Waveguide slot antenna 2 Waveguide 3 Radiation slot 4 Hole part 5 Feed slot 6 Conductive coating 10 Waveguide 11 1st waveguide formation member 11A 1st metal plate 11B 2nd metal plate 12 2nd Waveguide forming member 12a

Claims (6)

A waveguide having a waveguide extending in the tube axis direction, and a plurality of radiation slots provided at predetermined intervals along the tube axis direction of the waveguide. In the waveguide slot antenna constituted by the combined body of the first and second waveguide forming members whose cross sections in the extending direction portions have end shapes,
The first waveguide forming member is composed of a flat metal member having the plurality of radiation slots, and the second waveguide forming member is formed of the first waveguide forming member. A waveguide slot antenna comprising a resin member that is integrally held, and at least a defined surface of the waveguide among the waveguides is covered with a continuous conductive film. .   The first waveguide forming member is further provided with a hole portion provided on a front side in a radiation direction of a radio wave radiated to the outside through the radiation slot, and the radiation slot is disposed on an inner periphery. A waveguide slot antenna as described.   The waveguide slot antenna according to claim 2, wherein the first waveguide forming member is a laminate of a first metal plate having the radiation slot and a second metal plate having the hole. .   The waveguide slot antenna according to any one of claims 1 to 3, wherein the conductive coating is formed on the entire outer surface of the waveguide without a break. A waveguide having a waveguide extending in the tube axis direction, and a plurality of radiation slots provided at predetermined intervals along the tube axis direction of the waveguide. In the method of manufacturing a waveguide slot antenna constituted by a combined body of first and second waveguide forming members whose cross sections in the extending direction portions have end shapes,
The first waveguide forming member made of a flat metal member having a plurality of radiation slots is inserted, and the second waveguide forming member is injection-molded with resin to obtain the waveguide. Thereafter, the waveguide slot antenna is manufactured by subjecting the waveguide to a conductive coating forming process for covering at least the defined surface of the waveguide.   6. The method of manufacturing a waveguide slot antenna according to claim 5, wherein the conductive film is formed on the waveguide without masking the waveguide.

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