JP2003023303A - Production method for cylindrical waveguide, and cylindrical waveguide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method for cylindrical waveguide with which not only an axial ratio but also polarized wave conversion efficiency can be improved by arranging and fixing a dielectric board on a cylindrical waveguide with high position accuracy, and to provide a cylindrical waveguide. SOLUTION: The dielectric board is molded integrally with the cylindrical waveguide by resin molding so that the dielectric board can be fixed on the cylindrical waveguide. The cylindrical waveguide to which metal plating is applied, is arranged in a cavity part 26 which corresponds to a dielectric board part of a metal die having a cavity form with which the dielectric board and the cylindrical waveguide are synthesized, and a cavity 25 is filled with resins. Thus, the cylindrical waveguide with which the dielectric board 2 is integrally formed, is molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical waveguide used as a component of a microwave transmitting / receiving device such as a satellite communication antenna, and more particularly to a cylindrical waveguide having a dielectric plate as a phase shifter. The present invention relates to a method of manufacturing a wave tube and a cylindrical waveguide.

[0002]

2. Description of the Related Art In a microwave transmitter / receiver used for satellite communication or the like, a dielectric plate for converting a received circular polarized wave into a linear polarized wave and converting the linear polarized wave into a circular polarized wave during transmission ( 90 ° phase shifter) is required.

FIG. 6 shows a conventional technique (Japanese Patent Application Laid-Open No. 7-321502) of this type of microwave receiver. This prior art relates to a linearly-polarized primary radiator, which has an opening 101 at one end of a circular waveguide 100.
Is provided, and the end surface 102 is formed at the other end. A probe 103, a short-circuit plate 104, a probe 105, and a 90-degree phase shifter (dielectric plate) 106 are provided in this order from the opening 101 toward the terminal surface 102. Probe 1
The short-circuit plate 10 is located at a position of about 1/4 wavelength of the radio wave from 03.
4 is provided, and about 1
A probe 105 is provided at a position having a length of / 4 wavelength. The probes 103 and 105 are attached to a board 107 on which a signal processing circuit for reception is mounted. The dielectric plate 106 is sandwiched and fixed to the inner wall portion of the circular waveguide 100 so as to form an angle of 45 degrees with the short circuit plate 104.

[0004]

In the above prior art, since the dielectric plate 106 is clamped and fixed to the inner wall surface of the circular waveguide 100, the mounting accuracy and position (angle) accuracy of the dielectric plate are fixed. However, the axial ratio from the circular polarized wave to the linear polarized wave or the opposite axial ratio from the linear polarized wave to the circular polarized wave is poor, resulting in poor polarization conversion efficiency.

The present invention has been made in view of the above,
An object of the present invention is to obtain a cylindrical waveguide manufacturing method and a cylindrical waveguide in which a dielectric plate is arranged and fixed to the cylindrical waveguide with high positional accuracy to improve the axial ratio and, consequently, the polarization conversion efficiency.

[0006]

In order to achieve the above object, a method of manufacturing a cylindrical waveguide according to the present invention is a method of manufacturing a cylindrical waveguide having a dielectric plate as a phase shifter. A first step of resin-molding a cylindrical waveguide having an inner peripheral surface shape capable of holding a plate, a second step of plating the inner peripheral surface of the molded circular waveguide with a metal, and a step of applying the metal plating. The filled cylindrical waveguide in a cavity portion corresponding to the cylindrical waveguide portion of a mold having a cavity shape in which the dielectric plate and the cylindrical waveguide are combined, and filling the cavity with resin. And a third step of forming a cylindrical waveguide integrally formed with a dielectric plate.

According to the present invention, first, a cylindrical waveguide having an inner peripheral surface shape capable of holding a dielectric plate is resin-molded, and the inner peripheral surface of the molded circular waveguide is metal-plated. Next, the metal-plated cylindrical waveguide is placed in a cavity portion corresponding to the cylindrical waveguide portion of a die having a cavity shape in which a dielectric plate and the cylindrical waveguide are combined, and By filling the cavity with resin, a cylindrical waveguide integrally formed with the dielectric plate is formed.

In the method of manufacturing a cylindrical waveguide according to the next invention, in the above invention, in the third step, the resin portion of the dielectric plate is molded with a fluorine resin, an olefin resin or a styrene resin. It is characterized by doing.

According to the present invention, the resin portion of the dielectric plate is molded with fluorine resin, olefin resin or styrene resin.

In the method for manufacturing a cylindrical waveguide according to the next invention, in the above invention, in the third step, the resin portion of the dielectric plate is molded with a resin containing a glass balloon. To do.

According to the present invention, the dielectric constant of the dielectric plate is lowered by molding the resin portion of the dielectric plate with a resin containing glass balloons.

In the method of manufacturing a cylindrical waveguide according to the next invention, in the above invention, the resin portion of the dielectric plate is foam-molded in the third step.

According to this invention, the dielectric constant of the dielectric plate is lowered by foaming the resin portion of the dielectric plate.

In the method for manufacturing a cylindrical waveguide according to the next invention, in the above-mentioned invention, in the third step, a carbon dioxide gas or a nitrogen gas in a supercritical state is filled and foam molding is performed. Is characterized by.

According to the present invention, the dielectric constant of the dielectric plate is lowered by filling the one filled with carbon dioxide gas or nitrogen gas in the supercritical state and foam-molding the resin portion of the dielectric plate. .

A cylindrical waveguide according to the next invention is manufactured by using the manufacturing method according to any one of the above inventions.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the method for manufacturing a cylindrical waveguide according to the present invention will be described in detail below with reference to the accompanying drawings.

The cylindrical waveguide manufactured according to the present invention is used, for example, in the phase shifter 2 of the microwave transmitting / receiving antenna for the ground station of satellite communication shown in FIG.

The microwave transmitting / receiving antenna shown in FIG.
Parabolic antenna reflecting mirror 1, 90 ° phase shifter 2 for converting the circularly polarized wave reflected by the reflecting mirror 1 into a linearly polarized wave and converting the linearly polarized wave from the duplexer 3 into a circularly polarized wave, and a frequency Alternatively, a duplexer 3 for both transmission and reception, which has a waveguide branched to divide an electromagnetic wave into a transmission wave and a reception wave depending on the phase
And an electromagnetic wave in a waveguide mode propagating in the waveguide of the duplexer 3 is converted into a TEM mode electromagnetic wave for a microstrip line and a TEM from the microstrip line.
A waveguide / coaxial converter 4 for converting a mode electromagnetic wave into a waveguide mode. The duplexer 3 has a built-in short-circuit plate (not shown) made of a metal plate.

Embodiment 1. Next, a first embodiment of the present invention will be described with reference to FIGS. FIG. 2 shows a specific configuration of the phase shifter 2 shown in FIG.
FIG. 3 is a sectional view taken along the line AA. Further, FIG. 4 is a plan view of the dielectric plate 2.

The cylindrical waveguide 10 shown in FIGS. 2 and 3 is
It has a phase shifter 2 made of a dielectric plate for converting a circular polarized wave transmitted from a satellite into a linear polarized wave and a linear polarized wave to be transmitted into a circular polarized wave. The dielectric plate 2 is made of a fluorocarbon resin, an olefin resin, a styrene resin, or the like having a low dielectric constant, and as shown in FIG.
Recesses 2a for engaging and holding the inner peripheral portion of the cylindrical waveguide 10 are formed on both sides thereof. The dielectric plate 2 is installed between the inner peripheral walls of the cylindrical waveguide 10 that face each other.

The cylindrical waveguide 10 is, for example, LCP, AB.
It is made of resin such as S, AES, and SPS. The cylindrical waveguide 10 has flanges 12 at both ends,
Each flange 12 has a plurality of screw holes 13 formed therein. One flange 12 is provided to screw the cylindrical waveguide 10 to the reflecting mirror 1 of FIG. 1, and the other flange 12 is used to screw the cylindrical waveguide 10 to the duplexer 3 of FIG. It is provided in. Here, although not shown, appropriate positioning portions such as concave portions and convex portions are provided with the flange 12 so that the rotation angle of the dielectric plate 2 of the cylindrical waveguide 10 with respect to the reflecting mirror 1 and the duplexer 3 is uniquely determined. It is provided on the reflecting mirror 1 and the duplexer 3. A pair of opposed grooves 17 are formed on the inner peripheral surface of the cylindrical waveguide 10 so as to extend along the axial direction of the cylindrical waveguide 10. Further, in the central portion of the groove 17, a convex portion 15 with which the concave portion 2a of the dielectric plate 2 is locked is formed. The cylindrical waveguide 10 is composed of a metal plating 11 formed on the entire inner peripheral surface and a resin portion 14 other than the metal plating 11.

Next, the manufacturing procedure of the cylindrical waveguide 10 having the dielectric plate 2 therein will be described with reference to FIG.

(1) Preparation of Cylindrical Waveguide 10 The cylindrical waveguide 10 having one convex portion 15 for holding the dielectric plate 2 formed in the groove 17 of the inner peripheral surface has a nested structure. Injection molding is performed using a resin such as LCP, ABS, AES or SPS by using an appropriate technique such as placing a core in a mold or a cylindrical tube.

(2) Execution of metal plating Next, using electroless plating or the like, metal plating of nickel, copper or the like having a film thickness of skin depth or more is plated on the entire inner peripheral surface of the molded cylindrical waveguide. Enforce.

(3) Cylindrical waveguide 1 having a dielectric plate 2 inside
Preparation of 0 Next, the procedure for preparing the cylindrical waveguide 10 having the dielectric plate 2 therein will be described with reference to FIG. FIG. 5 conceptually shows a mold for producing the cylindrical waveguide 10.
In FIG. 5, the molds 20 to 22 and the slide core 2 are shown.
3 and the like to form a cavity region 25 having a shape corresponding to the dielectric plate 2 and a cavity region 26 having a shape corresponding to the cylindrical waveguide 10, the dielectric plate 2 and the cylindrical waveguide 10 are formed. A cavity 27 (cavity region 25 + cavity region 26) having a combined shape is formed. PL is a parting line and 24 is an angular pin.

Next, an actual processing result using the manufacturing method according to the first embodiment will be described. A liquid crystal polymer (C-810 manufactured by Polyplastics Co., Ltd.) was used as a resin material, and injection molding was performed by an injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd. to form a cylindrical waveguide 10. Electroless copper plating of about 3 μm and 0.5 μm on the manufactured cylindrical waveguide 10.
About nickel plating was performed. The plated cylindrical waveguide 10 is placed in a mold having a cavity shape in which the cylindrical waveguide 10 and a dielectric plate are combined, and the remaining cavity area is formed using an injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd. Tetrafluoroethylene-fluoroalkoxyethylene copolymer (Aflon PFA manufactured by Asahi Glass Co., Ltd., grade: P-62XP, dielectric constant: 2.1)
By filling the dielectric waveguide 2 and the holding portion (recess) 2a thereof into a cylindrical waveguide 10.
The axial ratio of the produced waveguide at 30 GHz was 0.4 dB.

As described above, according to the first embodiment, the dielectric plate 2 is integrally molded with the cylindrical waveguide 10 by resin molding, so that the dielectric plate 2 is fixed to the cylindrical waveguide 10. Therefore, the mounting accuracy and the position angle accuracy of the dielectric plate with respect to the cylindrical waveguide are improved, and further, the displacement of the dielectric plate 2 does not occur even under a severe outdoor environment. Therefore, it becomes possible to improve the axial ratio from the circular polarized wave to the linear polarized wave or the opposite axial ratio from the linear polarized wave to the circular polarized wave, and to improve the polarization conversion efficiency.

Embodiment 2. Next, a second embodiment of the present invention will be described. The dielectric constant of the dielectric plate 2 is preferably 5 or less, and when the dielectric constant of the dielectric plate 2 is high, the dielectric plate 2 needs to be thinly processed, which makes injection molding difficult. . Therefore, in the second embodiment, when a material having a high dielectric constant is used for the dielectric plate 2, the resin of the dielectric plate 2 is reduced in order to reduce the dielectric constant while ensuring a certain thickness of the dielectric plate 2. As a material, a resin containing glass balloons, hollow beads, or microballoons is used.

Next, the actual processing result using the manufacturing method according to the second embodiment will be described. ABS resin (EPX manufactured by Ube Sikon Corp.) as a resin material for the cylindrical waveguide 10.
-1100), injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd.
Then, a cylindrical waveguide 10 was prepared by injection molding. Electroless copper plating of about 3 μm and 0.5 μ on the fabricated cylindrical waveguide
About m of nickel was plated. The plated cylindrical waveguide 10 is placed in a mold having a cavity shape in which the cylindrical waveguide 10 and the dielectric plate 2 are combined, and the remaining cavity area is formed using an injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd. Polypropylene resin (Novatech PP manufactured by Japan Polychem,
By injecting resin (dielectric constant 2.1) containing 10 parts by weight of glass balloon (CEL-STAR made by Asahi Glass Co., Ltd., grade: Z-39EX) into grade: MAlH, dielectric constant: 2.5) A cylindrical waveguide 10 in which the plate 2 and its holding portion (recess) 2a were integrally formed was produced. 30 GHz of the produced cylindrical waveguide 10
The axial ratio at was 0.4 dB.

As described above, in the second embodiment,
Since a resin containing glass balloons, hollow beads, or microballoons is used as the resin of the dielectric plate 2, the dielectric constant of the dielectric plate 2 can be lowered.

Embodiment 3. Next, a third embodiment of the invention will be described. In the third embodiment, as in the second embodiment, a resin containing a foaming agent is used as the resin material of the dielectric plate 2 in order to reduce the dielectric constant of the dielectric plate 2. .

Next, an actual processing result using the manufacturing method according to the third embodiment will be described. SPS resin (Zarek SP150 manufactured by Idemitsu Petrochemical Co., Ltd.) is used as the resin material of the cylindrical waveguide 10, and the injection molding machine TH80 manufactured by Nissei Plastic Industry Co., Ltd.
A cylindrical waveguide 10 was manufactured by injection molding with E-9VE. The produced cylindrical waveguide was subjected to electroless copper plating of approximately 3 μm and nickel plating of approximately 0.5 μm. The plated cylindrical waveguide 10 is placed in a mold having a cavity shape in which the cylindrical waveguide 10 and the dielectric plate 2 are combined, and the remaining cavity area is formed using an injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd. ABS resin (Diapet A manufactured by Mitsubishi Rayon Co., Ltd.
By injecting a resin containing BS, grade: 3001, dielectric constant: 3) with 10 parts by weight of a foaming agent (Polysilane EB201 manufactured by Eiwa Chemical Industry Co., Ltd.), the dielectric plate 2 and its holding portion (recess) 2
A cylindrical waveguide 10 in which a was integrally formed was manufactured. The axial ratio of the produced waveguide at 30 GHz was 0.45 dB.

As described above, according to the third embodiment, the resin of the dielectric plate 2 is foam-molded with a foaming agent or the like, which can reduce the dielectric constant of the dielectric plate.

Fourth Embodiment Next, a fourth embodiment of the invention will be described. In this Embodiment 4, as in the case of Embodiment 2 or 3, the resin material of the dielectric plate 2 is filled with carbon dioxide gas or nitrogen gas in a supercritical state in order to lower the dielectric constant of the dielectric plate 2. I am trying to use the resin.

Next, an actual processing result using the manufacturing method according to the fourth embodiment will be described. A liquid crystal polymer (C-810 manufactured by Polyplastics Co., Ltd.) is used as a resin material of the cylindrical waveguide 10, and an injection molding machine TH manufactured by Nissei Plastic Industry Co., Ltd. is used.
The cylindrical waveguide 10 was manufactured by injection molding with 80E-9VE. The produced cylindrical waveguide was subjected to electroless copper plating of approximately 3 μm and nickel plating of approximately 0.5 μm. The plated cylindrical waveguide is placed in a mold having a cavity shape in which the cylindrical waveguide and the dielectric plate are combined, and J180E manufactured by Japan Steel Works
Using LIII-UPS, a tetrafluoroethylene-fluoroalkoxyethylene copolymer (Aflon PFA manufactured by Asahi Glass Co., Ltd., grade: P-62XP, dielectric constant: 2.1) as a fluororesin is applied to the remaining cavity region. After injection and melting of the resin, carbon dioxide gas in a supercritical state of 80 ° C. and 100 atm is filled and injection-molded to form a cylindrical waveguide 10 in which the dielectric plate 2 and its holding portion (recess) 2a are integrally formed. It was made. The axial ratio of the produced cylindrical waveguide 10 at 30 GHz was 0.4 dB.

As described above, in the fourth embodiment,
Since carbon dioxide or nitrogen gas in a supercritical state is filled and the resin of the dielectric plate 2 is foam-molded, the dielectric constant of the dielectric plate 2 can be lowered.

As the above-mentioned styrene resin,
Polystyrene, high-impact polystyrene, styrene-acrylonitrile copolymer, styrene-methylmethacrylate copolymer, styrene-acrylonitrile-methylmethacrylate copolymer, diene rubber reinforced styrene-acrylonitrile copolymer generally called ABS resin, AES Resin (ethylene / propyl rubber-reinforced styrene-acrylonitrile copolymer), AAS resin (acrylic rubber-reinforced styrene-acrylonitrile copolymer),
Examples thereof include MBS resin (diene rubber-reinforced styrene-methyl methacrylate copolymer) and ABSM resin (diene rubber-reinforced styrene-acrylonitrile-methyl methacrylate copolymer). The production method using these resins is not particularly limited, and a known bulk polymerization method, emulsion polymerization method, suspension polymerization method, solution polymerization method, a combination thereof or the like may be arbitrarily used.

Further, as the fluororesin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexafluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer, Polychlorotrifluoroethylene (PCTTE), chlorotrifluoroethylene / ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (P
VF) and the like. The production method using these resins is not particularly limited, and any known bulk polymerization method, emulsion polymerization method, suspension polymerization method, solution polymerization method, or a combination thereof may be used.

Examples of the olefin resin include ethylene homopolymers such as low-pressure polyethylene, medium-pressure polyethylene, high-pressure polyethylene, and linear low-density polyethylene, or ethylene-based resins such as ethylene / propylene copolymer, stereoregularity. Homopolymers such as organic polypropylene, propylene-based resins such as propylene / ethylene copolymer, and other α-olefins such as stereoregular poly-1-butene and stereoregular poly-4-methyl-1-pentene Examples include resin.

(Comparative Example) Next, as a comparative example of each of the above-described embodiments, an actual processing result using the conventional manufacturing method shown in FIG. 6 will be described. A liquid crystal polymer (C # 810 manufactured by Polyplastics Co., Ltd.) was injection-molded using an injection molding machine TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd., thereby forming a cylindrical waveguide having no convex portion 15 on the inner peripheral surface. Next, the dielectric plate having no recess 2a was replaced with a tetrafluoroethylene-fluoroalkoxyethylene copolymer (Aflo PFA manufactured by Asahi Glass Co., Ltd., grade: P-62).
XP, dielectric constant: 2.1) was used as a resin material, and injection molding was performed by injection molding revision TH80E-9VE manufactured by Nissei Plastic Industry Co., Ltd. A dielectric plate was inserted inside the cylindrical waveguide, and the dielectric plate was sandwiched and fixed by the inner peripheral surface of the cylindrical waveguide. This waveguide was plated with electroless copper of about 3 μm and nickel of about 0.5 μm. The axial ratio of the plated waveguide at 30 GHz is 0.
It was 6 dB.

The cylindrical waveguide manufactured by the manufacturing method of the present invention is not limited to the microwave transmitting / receiving device for satellite communication shown in FIG. 1, but is applied to any other communication equipment or electronic equipment. can do.

In the above embodiment, the dielectric plate 2 is formed by forming the concave portions 2a at both ends of the dielectric plate 2 and forming the pair of convex portions 15 on the inner peripheral surface of the cylindrical waveguide 10. Although it is configured to be held and fixed to the cylindrical waveguide 10, any other shape may be adopted as long as the dielectric plate 2 can be held and fixed to the cylindrical waveguide 10.

[0044]

As described above, according to the present invention, the dielectric plate is integrally molded with the cylindrical waveguide by resin molding so that the dielectric plate is fixed to the cylindrical waveguide. Therefore, the mounting accuracy and position angle accuracy of the dielectric plate to the cylindrical waveguide are improved, which improves the axial ratio from circular polarization to linear polarization or the opposite axial ratio from linear polarization to circular polarization. It is possible to improve the polarization conversion efficiency.

According to the next invention, since the resin portion of the dielectric plate is made of fluorine resin, olefin resin or styrene resin, it is possible to manufacture a dielectric plate having a low dielectric constant. Becomes

According to the next invention, since the resin portion of the dielectric plate is molded with the resin containing the glass balloon, the dielectric constant of the dielectric plate can be lowered.

According to the next invention, the resin portion of the dielectric plate is foam-molded with a foaming agent or the like, whereby the dielectric constant of the dielectric plate can be lowered.

According to the next invention, the resin portion of the dielectric plate is foam-molded by filling with carbon dioxide gas or nitrogen gas in a supercritical state. Can be lowered.

According to the next invention, since the cylindrical waveguide is manufactured by using the manufacturing method described in any one of the above, the accuracy and position of attachment of the dielectric plate to the cylindrical waveguide. The angle accuracy is improved, whereby the axial ratio from circular polarization to linear polarization or the opposite axial ratio from linear polarization to circular polarization can be improved, and polarization conversion efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of a microwave transmitting / receiving antenna to which a cylindrical waveguide manufactured according to the present invention is applied.

FIG. 2 is a perspective view showing an example of an external configuration of a cylindrical waveguide manufactured according to the present invention.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a plan view showing a dielectric plate included in a cylindrical waveguide.

FIG. 5 is a cross-sectional view showing an example of a mold for injection molding a cylindrical waveguide having a dielectric plate therein.

FIG. 6 is a diagram for explaining a conventional technique.

[Explanation of symbols]

1 reflecting mirror, 2 dielectric plate (phase shifter), 2a convex portion, 3
Duplexer, 4 waveguide / coaxial converter, 10 cylindrical waveguide, 11 metal plating, 12 flange, 13 screw hole,
14 resin parts, 15 concave parts, 17 grooves, 20, 21,
22 mold, 23 slide core, 24 angular pin, 25 cavity (cavity area), 26 cavity area, 27 cavity (cavity area).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Naoshi Yamada             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Hideki Asao             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Kazuhisa Hemi             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F-term (reference) 5J012 CA11 FA03 GA02

Claims (6)

[Claims] 1. A method of manufacturing a cylindrical waveguide having a dielectric plate as a phase shifter, comprising: a first step of resin-molding a cylindrical waveguide having an inner peripheral surface shape capable of holding the dielectric plate. A second step of plating the inner peripheral surface of the molded circular waveguide with a metal, and forming a cavity shape in which the dielectric plate and the cylindrical waveguide are combined with the cylindrical waveguide with the metal plating. A third step of forming a cylindrical waveguide in which a dielectric plate is integrally formed, by arranging the resin in the cavity portion corresponding to the cylindrical waveguide portion of the mold, and filling the cavity with resin. A method of manufacturing a cylindrical waveguide, comprising: 2. The cylindrical waveguide according to claim 1, wherein in the third step, the resin portion of the dielectric plate is molded with a fluorine resin, an olefin resin, or a styrene resin. Production method. 3. The method for manufacturing a cylindrical waveguide according to claim 1, wherein in the third step, the resin portion of the dielectric plate is molded with a resin containing glass balloons. 4. The method of manufacturing a cylindrical waveguide according to claim 1, wherein in the third step, the resin portion of the dielectric plate is foam-molded. 5. The method for producing a cylindrical waveguide according to claim 4, wherein in the third step, foam molding is performed by filling with carbon dioxide or nitrogen gas in a supercritical state. . 6. A cylindrical waveguide manufactured by using the manufacturing method according to claim 1.