Dielectric waveguide circuits

Abstract

A dielectric waveguide circuit capable of reducing the penetration of electromagnetic waves is provided. The present disclosure relates to a dielectric waveguide circuit comprising a central dielectric A1, a dielectric layer A2 disposed around the central dielectric A1, and a dielectric layer A3 disposed around the dielectric layer A2, wherein the central dielectric A1 comprises polytetrafluoroethylene, and the relative dielectric constants of the central dielectric A1, dielectric layer A2, and dielectric layer A3 at 25°C and 6 GHz are denoted as ε, respectively. A1 , ε A2 and ε A3 When ε A1 2.20 or less, ε A2 1.90 or less, ε A3 1.55 or less, ε A1 >ε A2 >ε A3 .

Description

Technical Field

[0001] The present disclosure relates to dielectric waveguide circuits. Background Art

[0002] It is well known that polytetrafluoroethylene molded bodies are used in waveguide lines for transmitting millimeter waves and submillimeter waves.

[0003] Patent Document 1 describes a dielectric waveguide line including a polytetrafluoroethylene molded body having a dielectric constant, a dielectric loss tangent, and a hardness within specific ranges.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: International Publication No. 2016 / 159314 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] An object of the present disclosure is to provide a dielectric waveguide line capable of reducing the penetration of electromagnetic waves.

[0009] Means for solving problems

[0010] The present disclosure relates to a dielectric waveguide circuit comprising a central dielectric A1, a dielectric layer A2 disposed around the central dielectric A1, and a dielectric layer A3 disposed around the dielectric layer A2. The central dielectric A1 comprises polytetrafluoroethylene. The relative dielectric constants of the central dielectric A1, the dielectric layer A2, and the dielectric layer A3 at 25°C and 6 GHz are denoted by ε. A1 , ε A2 and ε A3 When ε A1 2.20 or less, ε A2 1.90 or less, ε A3 1.55 or less, ε A1 >ε A2 >ε A3 .

[0011] The dielectric loss tangent of the central dielectric A1, dielectric layer A2 and dielectric layer A3 at 25°C and 6 GHz is expressed as tanδ A1 tanδ A2 and tanδ A3 When tanδ is preferably A1 2.20×10 -4 Below, tanδ A2 1.20×10 -4 Below, tanδA3 1.00×10 -4 the following.

[0012] The dielectric layers A2 and A3 preferably contain at least one resin A selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymers, tetrafluoroethylene / perfluoro(alkyl vinyl ether) copolymers, and polyolefins.

[0013] The present disclosure also relates to a dielectric waveguide line including a dielectric B containing polytetrafluoroethylene, wherein the dielectric B is seamlessly integrally formed of the same material and has a relative dielectric constant at 25° C. and 6 GHz that gradually decreases radially outward.

[0014] Effects of the Invention

[0015] According to the present disclosure, it is possible to provide a dielectric waveguide line capable of reducing penetration of electromagnetic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of a cross section of an example of a first dielectric waveguide line.

[0017] Figure 2 It is a schematic diagram of a cross section of an example of a second dielectric waveguide line. DETAILED DESCRIPTION

[0018] The present disclosure is described in detail below.

[0019] The present disclosure relates to a dielectric waveguide circuit comprising a central dielectric A1, a dielectric layer A2 disposed around the central dielectric A1, and a dielectric layer A3 disposed around the dielectric layer A2. The central dielectric A1 comprises polytetrafluoroethylene. The relative dielectric constants of the central dielectric A1, the dielectric layer A2, and the dielectric layer A3 at 25°C and 6 GHz are denoted by ε. A1 , ε A2 and ε A3 When ε A1 2.20 or less, ε A2 1.90 or less, ε A3 1.55 or less, ε A1 >ε A2 >ε A3 (Hereinafter, also referred to as the first dielectric waveguide line).

[0020] The first dielectric waveguide, having the above-described structure, can reduce the penetration of electromagnetic waves that leak through the outer layer of the dielectric waveguide. As a result, transmission loss can be reduced and the transmission efficiency of electromagnetic waves, particularly millimeter waves and submillimeter waves, can be improved.

[0021] The first dielectric waveguide line can also alleviate group delay within the dielectric waveguide line, thereby reducing errors.

[0022] In the first dielectric waveguide, the relative dielectric constants of the central dielectric A1, dielectric layer A2, and dielectric layer A3 at 25°C and 6 GHz are expressed as ε A1 , ε A2 and ε A3 When ε A1 2.20 or less, ε A2 1.90 or less, ε A3 1.55 or less, ε A1 >ε A2 >ε A3 When at least three layers of dielectric material with gradually decreasing relative permittivity are provided toward the outside of the waveguide, the relative permittivity difference between the layers can be reduced compared to a waveguide having only two layers of dielectric material, thereby reducing the penetration of electromagnetic waves.

[0023] ε A1 It is 2.20 or less, preferably 2.15 or less, and is preferably 1.80 or more, more preferably 1.90 or more, and further preferably 2.00 or more.

[0024] ε A2 It is 1.90 or less, preferably 1.80 or less, more preferably 1.75 or less, and is preferably 1.50 or more, more preferably 1.60 or more.

[0025] ε A3 It is 1.55 or less, preferably 1.45 or less, and preferably 1.01 or more, more preferably 1.25 or more, and further preferably 1.30 or more.

[0026] In the first dielectric waveguide line, ε A2 With ε A1 The ratio ε A2 / ε A1 It is preferably 0.65 to 0.95. A2 / ε A1 It is more preferably 0.92 or less, further preferably 0.90 or less, and more preferably 0.70 or more, further preferably 0.80 or more.

[0027] By making the ratio ε A2 / ε A1 Being within the above range, the penetration of electromagnetic waves can be further reduced.

[0028] In the first dielectric waveguide line, ε A3 With ε A2 The ratio ε A3 / εA2 It is preferably 0.65 to 0.95. A3 / ε A2 It is more preferably 0.92 or less, further preferably 0.90 or less, and more preferably 0.70 or more, further preferably 0.80 or more.

[0029] By making the ratio ε A3 / ε A2 Being within the above range, the penetration of electromagnetic waves can be further reduced.

[0030] One or more dielectric layers may be further provided between the core dielectric layer A1, dielectric layer A2, and dielectric layer A3. In this embodiment, the dielectric constant of each layer at 25°C and 6 GHz preferably decreases toward the outer layers. This further reduces electromagnetic wave penetration.

[0031] One or more dielectric layers may be further provided around dielectric layer A3. In this embodiment, the dielectric constant of the one or more dielectric layers at 25°C and 6 GHz preferably decreases toward the outer layers. This further reduces electromagnetic wave penetration.

[0032] It should be noted that the relative dielectric constant of the one or more dielectric layers at 25° C. and 6 GHz may be ε A3 above.

[0033] The relative dielectric constants of the central dielectric A1 and each dielectric layer were measured by cutting out a 2.0 mm x 2.0 mm x 110 mm square rod-shaped sample from the dielectric to be measured at 25° C. and 6 GHz using a cavity resonator.

[0034] If the dielectric being measured consists of only one resin, the specific gravity of that resin can be measured and the relative permittivity calculated based on the correlation between the specific gravity and the relative permittivity of the resin. Typically, the specific gravity and relative permittivity of a resin have a linear relationship. Those skilled in the art can pre-measure the relative permittivity by varying the specific gravity, and then determine the relationship for each resin from the resulting numerical data.

[0035] The above-mentioned specific gravity is measured by a submerged weighing method (in accordance with JIS Z 8807).

[0036] The specific gravity of the core dielectric A1 is preferably 1.500 or higher, more preferably 1.700 or higher, and even more preferably 1.900 or higher. The upper limit is not particularly limited and may be 2.250.

[0037] The specific gravity of the dielectric layer A2 is preferably 1.700 or less, more preferably 1.500 or less, and even more preferably 1.400 or less, and is preferably 0.350 or more, more preferably 0.900 or more, and even more preferably 1.100 or more.

[0038] The specific gravity of the dielectric layer A3 is preferably 1.000 or less, more preferably 0.850 or less, and is preferably 0.010 or more, more preferably 0.450 or more, and further preferably 0.550 or more.

[0039] In the first dielectric waveguide line, it is preferable that the specific gravity of the dielectric layer A2 is smaller than that of the core dielectric A1 , and the specific gravity of the dielectric layer A3 is smaller than that of the dielectric layer A2 .

[0040] The dielectric loss tangent of the central dielectric A1, dielectric layer A2 and dielectric layer A3 at 25°C and 6 GHz is expressed as tanδ A1 tanδ A2 and tanδ A3 When tanδ is preferably A1 2.20×10 -4 Below, tanδ A2 1.20×10 -4 Below, tanδ A3 1.00×10 -4 the following.

[0041] By setting the dielectric loss tangent of each layer to be within the above range, the penetration of electromagnetic waves can be further reduced.

[0042] tanδ A1 More preferably, it is 2.10×10 -4 Below, and can be 0.10×10 -4 Above, it can also be 0.50×10 -4 above.

[0043] tanδ A2 More preferably, it is 1.00×10 -4 Below, and can be 0.10×10 -4 Above, it can also be 0.30×10 -4 above.

[0044] tanδ A3 More preferably, it is 0.80×10 -4 Below, and can be 0.10×10 -4 Above, it can also be 0.20×10 -4 above.

[0045] In the first dielectric waveguide line, tanδA1 >tanδ A2 >tanδ A3 It is also one of the preferred methods.

[0046] The dielectric loss tangent of the central dielectric A1 and each dielectric layer was measured by cutting a 2.0 mm x 2.0 mm x 110 mm square rod-shaped sample from the dielectric to be measured at 25° C. and 6 GHz using a cavity resonator.

[0047] The central dielectric A1 comprises PTFE. The above-mentioned PTFE can be a TFE homopolymer consisting solely of tetrafluoroethylene (TFE), or it can be a modified PTFE. The modified PTFE comprises a TFE unit and a modified monomer unit based on a modified monomer that can copolymerize with TFE. In this specification, the above-mentioned modified monomer unit refers to a part of the molecular structure of PTFE, that is, a part derived from the modified monomer. The modified PTFE can be uniformly modified, or it can be a modified PTFE with a core-shell structure described later.

[0048] The modifying monomer is not particularly limited as long as it can copolymerize with TFE. Examples thereof include perfluoroolefins such as hexafluoropropylene [HFP]; perhaloolefins such as chlorotrifluoroethylene [CTFE]; hydrogen-containing fluoroolefins such as trifluoroethylene and vinylidene fluoride [VDF]; perfluorovinyl ethers; (perfluoroalkyl)ethylenes; ethylene; and fluorinated vinyl ethers having a nitrile group. The modifying monomers used may be one or two or more.

[0049] The perfluorovinyl ether is not particularly limited, and examples thereof include the following general formula (1):

[0050] CF2=CF-ORf 1 (1)

[0051] (Where Rf 1 In this specification, the above-mentioned "perfluoroorganic group" refers to an organic group in which all hydrogen atoms bonded to carbon atoms are replaced by fluorine atoms. The above-mentioned perfluoroorganic group may have an ether oxygen.

[0052] Examples of the perfluorovinyl ether include Rf in the general formula (1): 1 Perfluoro(alkyl vinyl ether) [PAVE] having a perfluoroalkyl group having 1 to 10 carbon atoms. The perfluoroalkyl group preferably has 1 to 5 carbon atoms.

[0053] Examples of the perfluoroalkyl group in PAVE include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, and perfluorohexyl, with perfluoropropyl being preferred. PAVE is preferably perfluoropropyl vinyl ether [PPVE] in which the perfluoroalkyl group is perfluoropropyl.

[0054] As the perfluorovinyl ether, further examples include Rf in the general formula (1): 1 It is a perfluoro(alkoxyalkyl) substance having 4 to 9 carbon atoms, Rf 1 is the following formula:

[0055] [Chemistry 1]

[0056]

[0057] (wherein m represents 0 or an integer of 1 to 4) and Rf 1 is the following formula:

[0058] [Chemistry 2]

[0059]

[0060] (wherein n represents an integer of 1 to 4) and the like.

[0061] The (perfluoroalkyl)ethylene (PFAE) is not particularly limited, and examples thereof include (perfluorobutyl)ethylene (PFBE) and (perfluorohexyl)ethylene (PFHE).

[0062] As the fluorine-containing vinyl ether having a nitrile group, CF2=CFORf is more preferred. 2 CN (where Rf 2 represents an alkylene group having 2 to 7 carbon atoms in which an oxygen atom may be inserted between two carbon atoms) a fluorine-containing vinyl ether.

[0063] The modifying monomer in the modified PTFE is preferably at least one selected from the group consisting of HFP, CTFE, VDF, PPVE, PFAE, and ethylene, more preferably PAVE, and even more preferably PPVE.

[0064] The modified PTFE may have a core-shell structure composed of a particle core and a particle shell.

[0065] The polymerized unit based on the modified monomer (modified monomer unit) is preferably in the range of 0.00001 to 1.0 mass %. As the lower limit of the modified monomer unit, it is more preferably 0.0001 mass %, more preferably 0.0005 mass %, and further preferably 0.001 mass %. As the upper limit of the modified monomer unit, it is preferably 0.90 mass %, more preferably 0.50 mass %, further preferably 0.40 mass %, further more preferably 0.30 mass %, especially more preferably 0.10 mass %, particularly preferably 0.08 mass %, particularly preferably 0.05 mass %, and particularly preferably 0.01 mass %.

[0066] In this specification, the content of each monomer constituting PTFE can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.

[0067] The PTFE preferably has a fibrillating property. The fibrillating property refers to a property that allows the PTFE to be easily fibrillated and formed into fibrils.

[0068] The presence or absence of fibrillation can be determined using paste extrusion, a typical method for molding powders made by emulsion polymerization of TFE, known as high-molecular-weight PTFE powders. This is because high-molecular-weight PTFE powders generally exhibit fibrillation when paste extrusion is possible. If the unfired molded article obtained by paste extrusion lacks substantial strength or elongation, for example, if the elongation is 0% and the article breaks when stretched, it is considered to be non-fibrillating.

[0069] The PTFE preferably has non-melt secondary processability. The non-melt secondary processability refers to the property that the melt flow rate cannot be measured at a temperature higher than the crystallization melting point according to ASTM D-1238 and D-2116.

[0070] The standard specific gravity [SSG] of the PTFE is preferably 2.13 to 2.23, more preferably 2.15 to 2.19. The standard specific gravity is a value measured by the water displacement method according to ASTM D-792 using a sample molded according to ASTM D 4895-98.

[0071] The first melting point of the PTFE is preferably 333-347°C, more preferably 335-345°C. The first melting point is the temperature corresponding to the maximum value in the heat of fusion curve obtained when the temperature of PTFE, which has not been heated to a temperature of 300°C or higher, is increased at a rate of 10°C / minute using a differential scanning calorimeter (DSC).

[0072] In addition, high-molecular-weight PTFE and low-molecular-weight PTFE can also be used as the PTFE. The first melting point of the high-molecular-weight PTFE is preferably 333-347°C, more preferably 335-345°C. The first melting point of the low-molecular-weight PTFE is preferably 322-333°C, more preferably 324-332°C. The first melting point is the temperature corresponding to the maximum value in the heat of fusion curve described below, which is a heat of fusion curve obtained when the temperature of PTFE, which has not been heated to a temperature of 300°C or higher, is increased at a rate of 10°C / minute using a differential scanning calorimeter (DSC).

[0073] The mass ratio of the high molecular weight PTFE to the low molecular weight PTFE is preferably 80 / 20 to 99 / 1, more preferably 85 / 15 to 97 / 3, and even more preferably 90 / 10 to 95 / 5.

[0074] The core dielectric A1 may further contain a resin other than the above-mentioned PTFE. Preferred resins other than PTFE include TFE / hexafluoropropylene [HFP] copolymer [FEP], TFE / perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA], and polyolefins.

[0075] Examples of resins other than the above-mentioned PTFE include ethylene / TFE copolymer [ETFE], polyvinylidene fluoride [PVdF], and polychlorotrifluoroethylene [PCTFE].

[0076] The core dielectric A1 may contain other components. Examples of these other components include surfactants, antioxidants, light stabilizers, fluorescent brighteners, colorants, pigments, dyes, and fillers. Examples include powders or fiber powders of carbon black, graphite, aluminum oxide, mica, silicon carbide, boron nitride, titanium oxide, bismuth oxide, bronze, gold, silver, copper, and nickel.

[0077] The core dielectric A1 may contain high dielectric constant inorganic particles as the above-mentioned other components. Examples of the high dielectric constant inorganic particles include barium titanate, calcium titanate, strontium titanate, magnesium titanate, lead titanate, zinc titanate, lead zirconate, calcium zirconate, strontium zirconate, barium zirconate titanate, and lead zirconate titanate.

[0078] Even when the core dielectric A1 contains a resin other than the PTFE or the other components, the core dielectric A1 preferably contains 99.0% by mass or more of the PTFE, more preferably 99.9% by mass or more of the PTFE, relative to the core dielectric A1.

[0079] The dielectric layers A2 and A3 preferably contain at least one resin A selected from the group consisting of PTFE, TFE / hexafluoropropylene [HFP] copolymer [FEP], TFE / perfluoro(alkyl vinyl ether) [PAVE] copolymer [PFA], and polyolefin.

[0080] As the PTFE as the resin A, the same PTFE as those exemplified as the PTFE that can be used in the core dielectric A1 can be mentioned.

[0081] The above-mentioned FEP is not particularly limited, but a copolymer in which the molar ratio of TFE units to HFP units (TFE units / HFP units) is 70 / 30 or more and less than 99 / 1 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and a further preferred molar ratio is 80 / 20 or more and 97 / 3 or less. If the TFE unit is too little, the mechanical properties tend to decrease; if it is too much, the melting point is too high and the moldability tends to decrease. FEP is also preferably a copolymer in which the monomer units derived from monomers copolymerizable with TFE and HFP are 0.1 to 10 mol%, and the total of TFE units and HFP units is 90 to 99.9 mol%. Examples of monomers copolymerizable with TFE and HFP include PAVE and alkyl perfluorovinyl ether derivatives.

[0082] The melting point of FEP is preferably 150-320° C., more preferably 200-300° C., and even more preferably 240-280° C. The melting point is the temperature corresponding to the maximum value in the heat of fusion curve when the temperature is increased at a rate of 10° C. / min using a differential scanning calorimeter (DSC).

[0083] The melt flow rate (MFR) of the FEP is preferably 0.01 to 100 g / 10 min, more preferably 0.1 to 80 g / 10 min, further preferably 1 to 60 g / 10 min, and particularly preferably 1 to 50 g / 10 min.

[0084] In this specification, MFR is a value measured at a temperature of 372° C. and a load of 5 kg in accordance with ASTM D 1238.

[0085] As PAVE in the above-mentioned PFA, for example, the formula (10) can be cited:

[0086] CF2=CF-ORf 10 (10)

[0087] (Where Rf 10 represents a perfluoroalkyl group having 1 to 10 carbon atoms, preferably 1 to 5 carbon atoms), among which perfluoro(methyl vinyl ether) [PMVE], perfluoro(ethyl vinyl ether) [PEVE], and perfluoro(propyl vinyl ether) [PPVE] are preferred.

[0088] The above-mentioned PFA is not particularly limited, but a copolymer in which the molar ratio of TFE units to PAVE units (TFE units / PAVE units) is 70 / 30 or more and less than 99.5 / 0.5 is preferred. A more preferred molar ratio is 70 / 30 or more and 98.9 / 1.1 or less, and a further preferred molar ratio is 80 / 20 or more and 98.5 / 1.5 or less. If the TFE unit is too little, the mechanical properties tend to decrease; if it is too much, the melting point is too high and the moldability tends to decrease. The above-mentioned PFA may be a copolymer consisting only of TFE and PAVE, and is also preferably a copolymer in which the monomer units from monomers copolymerizable with TFE and PAVE are 0.1 to 10 mol%, and the total of TFE units and PAVE units is 90 to 99.9 mol%. As monomers copolymerizable with TFE and PAVE, HFP, CZ 1 Z 2 =CZ 3 (CF2)nZ 4 (Where Z 1 , Z 2 and Z 3 are the same or different, representing a hydrogen atom or a fluorine atom, Z 4 represents a hydrogen atom, a fluorine atom or a chlorine atom, and n represents an integer from 2 to 10), and a vinyl monomer represented by CF2=CF-OCH2-Rf 11 (Where Rf 11 represents a perfluoroalkyl group having 1 to 5 carbon atoms), and the like.

[0089] The melting point of PFA is preferably 180-340° C., more preferably 230-330° C., and even more preferably 280-320° C. The melting point is the temperature corresponding to the maximum value in the heat of fusion curve when the temperature is increased at a rate of 10° C. / min using a differential scanning calorimeter (DSC).

[0090] The MFR of the PFA is preferably 0.1 to 100 g / 10 minutes, more preferably 0.5 to 90 g / 10 minutes, and even more preferably 1.0 to 85 g / 10 minutes.

[0091] In this specification, the content of each monomer unit constituting the fluororesin can be calculated by appropriately combining NMR, FT-IR, elemental analysis, and fluorescent X-ray analysis depending on the type of monomer.

[0092] The FEP and PFA are preferably fluorinated. The fluorination can reduce terminal groups (unstable terminal groups) such as -COOH, -CH2OH, -COF, and -CONH2 that are thermally and electrically unstable, thereby improving transmission efficiency.

[0093] The fluorination treatment can be carried out by a known method, for example, by bringing a fluorinated resin that has not been fluorinated into contact with a fluorine-containing compound.

[0094] Examples of the fluorine-containing compounds include fluorine radical sources that generate fluorine radicals under fluorination conditions, such as F2 gas, CoF3, AgF2, UF6, OF2, N2F2, CF3OF, and fluorinated halogens (such as IF5, ClF3).

[0095] Examples of the polyolefin include polyethylene and polypropylene, and polyethylene is preferred among them.

[0096] Resin A is preferably at least one selected from the group consisting of PTFE, FEP, PFA and polyolefins, more preferably at least one selected from the group consisting of PTFE and polyolefins, further preferably at least one selected from the group consisting of PTFE and polyethylene, and particularly preferably PTFE.

[0097] The resin A is preferably a polyolefin, and more preferably polyethylene.

[0098] The dielectric layers A2 and A3 may further contain other components. Examples of the other components include the same components as those that can be used in the core dielectric A1.

[0099] The dielectric layers A2 and A3 preferably contain 99.0% by mass or more of the resin A, and more preferably contain 99.9% by mass or more of the resin A, based on the total mass of the dielectric layers A2 and A3.

[0100] The first dielectric waveguide may further include a protective layer around dielectric layer A3 (or, if a further dielectric layer is provided outside dielectric layer A3, around the dielectric layer). This protective layer is provided to protect the inner dielectric layer and is optional. The protective layer may be made of materials such as polyvinyl chloride, polyolefin, and fluororesin.

[0101] The first dielectric waveguide line is suitably manufactured by a manufacturing method including, for example, a step of molding PTFE to obtain a core dielectric A1 and a step of forming dielectric layers A2 and A3 around the core dielectric A1.

[0102] The core dielectric A1 is obtained by molding the above-mentioned PTFE. The core dielectric A1 can be formed of an unfired PTFE molded body, a semi-fired PTFE molded body, or a fired PTFE molded body.

[0103] The unfired PTFE molded body can be obtained by, for example, paste extrusion molding a mixture of a powder containing unfired PTFE and an extrusion aid. Furthermore, after paste extrusion molding, the extrusion aid can be removed by drying the resulting extrudate. The mixture can be obtained by mixing the unfired PTFE powder and the extrusion aid using a known method, aging for 1 to 24 hours, and preforming the mixture under a pressure of 0.5 to 2.0 MPa. Paste extrusion can be performed at an extrusion pressure of 2 to 100 MPa.

[0104] The unsintered PTFE molded body can be stretched as needed to produce an unsintered stretched PTFE molded body.

[0105] The uncalcined PTFE is PTFE that has not been subjected to a heating history of 326° C. or higher, and preferably is PTFE that has not been subjected to a heating history of 300° C. or higher.

[0106] The semi-fired PTFE molded body is obtained, for example, by heating an unfired PTFE molded body at 320-340°C, preferably 330-340°C, for 10 seconds to 180 minutes. The semi-fired PTFE molded body is preferably obtained without heating the unfired PTFE to a temperature exceeding 345°C.

[0107] The heating can be performed using a salt bath, a sand bath, a hot air circulation electric furnace, or the like.

[0108] The calcined PTFE molded body is obtained, for example, by heating an uncalcined PTFE molded body at a temperature not lower than the first melting point of PTFE, preferably higher than 340°C, more preferably higher than 345°C, and even more preferably higher than 350°C, for 10 seconds to 180 minutes.

[0109] The heating can be performed using a salt bath, a sand bath, a hot air circulation electric furnace, or the like.

[0110] By adjusting the stretching and firing conditions, the specific gravity and crystallinity of the resin can be adjusted, and the relative dielectric constant of the core dielectric A1 can be adjusted. Generally, the higher the stretching ratio and the lower the crystallinity, the lower the relative dielectric constant.

[0111] Dielectric layers A2 and A3 can be formed, for example, by extruding resin A constituting each of dielectric layers A2 and A3 around core dielectric A1 using a known method. Resin A for dielectric layer A2 and resin A for dielectric layer A3 can be extruded separately or co-extruded.

[0112] The (co)extrusion is preferably paste (co)extrusion when the resin A is PTFE, and preferably melt (co)extrusion when the resin A is a melt-processable resin. Paste co-extrusion can be performed, for example, by following the method described in Japanese Patent Application Laid-Open No. 2001-357730.

[0113] Dielectric layers A2 and A3 can also be formed by wrapping a sheet (tape) containing the resin A that constitutes each of dielectric layers A2 and A3 around core dielectric layer A1. Alternatively, they can be formed by covering core dielectric layer A1 with a tube containing the resin A that constitutes each of dielectric layers A2 and A3. The above-described method using a sheet (tape) or tube can be implemented, for example, by following the method described in International Publication No. 2012 / 07760 or International Publication No. 2016 / 159314.

[0114] When forming dielectric layers A2 and A3, resin A can be subjected to treatments such as stretching, foaming, and firing. By adjusting the presence or absence of these treatments and the treatment conditions, the specific gravity and crystallinity of the resin can be adjusted, and the relative dielectric constant of dielectric layers A2 and A3 can be adjusted. Generally, a higher stretch ratio or foaming ratio, and a lower crystallinity, results in a lower relative dielectric constant.

[0115] When resin A is PTFE, the relative dielectric constant is preferably adjusted by stretching or firing. The method of stretching and firing is not particularly limited and can adopt known methods. In addition, the relative dielectric constant can also be adjusted by the foaming method described in International Publication No. 2005 / 019320.

[0116] When resin A is FEP or PFA, the adjustment of relative dielectric constant is preferably carried out by foaming. As the foaming method, there is no particular limitation. For example, FEP or PFA can be enumerated and put into a screw extruder designed for foaming operation, using known methods such as the method for continuous gas injection. As the above-mentioned gas, for example, gases such as chlorodifluoromethane, nitrogen, carbon dioxide or a mixture of the above-mentioned gases can be used. The above-mentioned gas can be imported into the molten resin in the extruder in the form of pressurized gas, or can produce gas by mixing a chemical foaming agent in the molten resin. In addition, with the miniaturization and uniform distribution of bubbles for the purpose, it is also possible to make the resin have a foaming nucleating agent.

[0117] When the resin A is a polyolefin, the relative dielectric constant is preferably adjusted by foaming. The foaming method is not particularly limited, and examples thereof include well-known methods such as melt foaming.

[0118] The dielectric layers A2 and A3 preferably contain at least one selected from the group consisting of unfired PTFE, stretched PTFE, foamed FEP, foamed PFA and foamed polyolefin, more preferably contain at least one selected from the group consisting of unfired PTFE, stretched PTFE and foamed polyolefin, further preferably contain at least one selected from the group consisting of unfired PTFE, stretched PTFE and foamed polyethylene, and particularly preferably contain at least one selected from the group consisting of unfired PTFE and stretched PTFE.

[0119] The dielectric layers A2 and A3 also preferably comprise foamed polyolefin, further preferably foamed polyethylene.

[0120] The first dielectric waveguide preferably includes a core dielectric A1, dielectric layer A2, and dielectric layer A3 as waveguide media. Furthermore, the first dielectric waveguide preferably transmits high frequencies such as millimeter waves and submillimeter waves by utilizing the relative permittivity difference between dielectrics.

[0121] The present disclosure also relates to a dielectric waveguide line having a dielectric B containing PTFE, wherein the dielectric B is seamlessly integrally formed from the same material and has a relative dielectric constant at 25°C and 6 GHz that gradually decreases radially outward (hereinafter also referred to as a second dielectric waveguide line).

[0122] The second dielectric waveguide line has the above-described structure, so that the penetration of electromagnetic waves can be reduced. As a result, the transmission loss can be reduced and the transmission efficiency of electromagnetic waves, particularly millimeter waves and submillimeter waves, can be improved.

[0123] The second dielectric waveguide line can also alleviate group delay within the dielectric waveguide line, thereby reducing errors.

[0124] In the second dielectric waveguide, dielectric B is seamlessly integrated from the same material, and its relative permittivity at 25°C and 6 GHz gradually decreases radially outward. This gradually decreasing relative permittivity reduces the difference in relative permittivity between components compared to a waveguide comprising two dielectric layers with different relative permittivity, thereby reducing electromagnetic wave penetration. Furthermore, seamlessly integrating the dielectric from the same material eliminates the need for forming two or more dielectric layers.

[0125] In the dielectric B, it is preferable that the relative dielectric constant decreases continuously (without steps) toward the outside in the radial direction.

[0126] In dielectric B, the decrease rate of relative dielectric constant is preferably 0.005% or more per 1 mm radially outward, more preferably 0.01% or more, further preferably 0.1% or more, and preferably 20% or less, more preferably 10% or less, further preferably 5% or less.

[0127] The relative dielectric constant of the central portion of the dielectric B is preferably 2.30 or less, more preferably 2.25 or less, and is preferably 1.90 or more, more preferably 2.00 or more, and even more preferably 2.10 or more.

[0128] The relative dielectric constant of the outer peripheral portion of the dielectric B is preferably 2.10 or less, more preferably 2.00 or less, and is preferably 1.30 or more, more preferably 1.50 or more, and even more preferably 1.70 or more.

[0129] When the second dielectric waveguide is curved, the difference in relative permittivity (Δε) between the center and periphery of dielectric B (center - periphery) is preferably 0.5 or greater. The upper limit may be 1.50. When the second dielectric waveguide is linear, Δε is preferably greater than 0 and less than 0.5.

[0130] One or more dielectric layers may be further provided around dielectric B. In this embodiment, the relative dielectric constant of the one or more dielectric layers at 25°C and 6 GHz is preferably lower than the relative dielectric constant of the outer peripheral portion of dielectric B, and preferably, the relative dielectric constant decreases toward the outer layers. This can further reduce the penetration of electromagnetic waves.

[0131] Note that the relative dielectric constant of the one or more dielectric layers at 25° C. and 6 GHz may be equal to or greater than that of the outer periphery of the dielectric B.

[0132] The relative dielectric constants of each portion and each dielectric layer of dielectric B were measured by cutting out a 2.0 mm x 2.0 mm x 110 mm square rod-shaped sample from the portion to be measured at 25° C. and 6 GHz using a cavity resonator.

[0133] If the dielectric being measured consists of only one resin, the specific gravity of the portion being measured can also be measured, and the relative dielectric constant calculated based on the correlation between the specific gravity and relative dielectric constant of the resin. Typically, the specific gravity and relative dielectric constant of a resin have a linear relationship. Those skilled in the art can use the numerical data obtained from measuring the relative dielectric constant while varying the specific gravity to determine the relationship for each resin.

[0134] The above-mentioned specific gravity is measured by a submerged weighing method (according to JIS Z 8807).

[0135] In the dielectric B, the specific gravity preferably decreases gradually toward the outside in the radial direction. It is also preferable that the specific gravity decreases continuously (without steps) toward the outside in the radial direction.

[0136] The dielectric loss tangent of the center portion of dielectric B is preferably 2.20×10 -4 less than 2.10×10 -4 Below, and can be 0.10×10 -4 Above, it can also be 0.50×10 -4 above.

[0137] The dielectric loss tangent of the center portion of dielectric B is preferably 1.00×10 -4 less than 0.80×10 -4 Below, and can be 0.10×10 -4 Above, it can also be 0.20×10 -4 above.

[0138] In the dielectric B, the dielectric loss tangent preferably decreases gradually toward the outside in the radial direction. It is also preferable that the dielectric loss tangent decreases continuously (without steps) toward the outside in the radial direction.

[0139] The dielectric loss tangent of dielectric B was measured by cutting a 2.0 mm x 2.0 mm x 110 mm square rod-shaped sample from the dielectric to be measured at 25° C. and 6 GHz using a cavity resonator.

[0140] The dielectric B contains PTFE. Examples of PTFE that can be used in the dielectric B include the same PTFE that can be used in the core dielectric A1.

[0141] The dielectric B may further contain resins and other components other than the PTFE. Examples of the resins and other components other than the PTFE include the same resins and other components that can be used in the core dielectric A1.

[0142] Even when dielectric B contains a resin other than PTFE or the other components, dielectric B preferably contains 99.0% by mass or more of PTFE, more preferably 99.9% by mass or more of PTFE, relative to dielectric B.

[0143] The dielectric B may be the innermost layer in the second dielectric waveguide line.

[0144] The second dielectric waveguide may further include a protective layer around dielectric B (or around the dielectric layer if a further dielectric layer is provided outside dielectric B). This protective layer is provided to protect the inner dielectric layer and its placement is optional. The protective layer may be made of a material such as polyvinyl chloride, polyolefin, or fluororesin.

[0145] The second dielectric waveguide line is suitably manufactured, for example, by a manufacturing method comprising the following steps: a step of molding unfired PTFE to obtain an unfired PTFE molded body; a step of heating the unfired PTFE molded body to a temperature above the first melting point of the PTFE; and a step of rapidly cooling the periphery of the heated PTFE molded body to obtain dielectric B.

[0146] When the periphery of the heated PTFE molded body is rapidly cooled to a temperature above the first melting point of the PTFE, the crystallinity and relative dielectric constant of the PTFE near the periphery decrease. In contrast, heat dissipation near the center of the PTFE molded body is less likely than near the periphery, leading to slower cooling, increased crystallinity and a higher relative dielectric constant. As a result, a dielectric B is obtained that is seamlessly integrated from the same material and has a relative dielectric constant that gradually decreases radially outward.

[0147] The uncalcined PTFE is PTFE that has not been subjected to a heating history of 326° C. or higher, and preferably is PTFE that has not been subjected to a heating history of 300° C. or higher.

[0148] The unfired PTFE molded body can be obtained by, for example, paste extrusion molding a mixture of a powder containing unfired PTFE and an extrusion aid. Furthermore, after paste extrusion molding, the extrusion aid can be removed by drying the resulting extrudate. The mixture can be obtained by mixing the unfired PTFE powder and the extrusion aid using a known method, aging for 1 to 24 hours, and preforming the mixture under a pressure of 0.5 to 2.0 MPa. Paste extrusion can be performed at an extrusion pressure of 2 to 100 MPa.

[0149] The heating is performed at a temperature not lower than the first melting point of the PTFE, preferably higher than 340° C., more preferably higher than 345° C., and even more preferably higher than 350° C. The heating time is preferably 10 seconds to 180 minutes.

[0150] The heating can be performed using a salt bath, a sand bath, a hot air circulation electric furnace, or the like.

[0151] The temperature drop rate in the rapid cooling is preferably 100° C. / hour or higher, more preferably 200° C. / hour or higher, and even more preferably 300° C. / hour or higher.

[0152] The rapid cooling can be performed, for example, by placing the PTFE molded body heated to a temperature equal to or higher than the first melting point of the PTFE in an atmosphere at 100° C. or lower, or in water at 100° C. or lower.

[0153] The temperature of the atmosphere or water is preferably 50°C or lower, more preferably 30°C or lower, and preferably higher than 0°C.

[0154] In addition, the second dielectric waveguide line can also be appropriately manufactured by a manufacturing method including the following steps: a step of covering a metal wire with an unfired PTFE molded body; a step of heating the above-mentioned metal wire to thereby heat the center portion of the above-mentioned unfired PTFE molded body to a temperature above the first melting point of the above-mentioned PTFE; and a step of removing the above-mentioned metal wire from the PTFE molded body obtained by heating to thereby obtain dielectric B.

[0155] By heating the unfired PTFE molded body from its center using a metal wire, the crystallinity and relative dielectric constant of the PTFE near the center increase. In contrast, the outer periphery is not heated as much as the center, resulting in a decrease in crystallinity and relative dielectric constant. The result is a dielectric B seamlessly formed from the same material, with a relative dielectric constant that gradually decreases radially outward.

[0156] The coating can be achieved, for example, by paste extrusion molding a mixture of unfired PTFE powder and an extrusion aid onto a metal wire. Alternatively, the extrusion aid can be removed by drying the resulting extrudate after the paste extrusion molding. The mixture can be obtained by mixing the unfired PTFE powder and the extrusion aid using a known method, aging for 1 to 24 hours, and preforming the mixture under a pressure of 0.5 to 2.0 MPa. The paste extrusion can be performed at an extrusion pressure of 2 to 100 MPa.

[0157] The metal wire can be heated by applying voltage to the metal wire and passing electricity therethrough. The metal wire is preferably a metal wire that generates heat when electricity is passed therethrough, and examples thereof include nicromium wire, iron chromium wire, and silver-plated copper wire.

[0158] The heating is performed so that the center portion of the uncalcined PTFE molded body reaches a temperature equal to or higher than the first melting point of PTFE, preferably higher than 340° C., more preferably higher than 345° C., and even more preferably higher than 350° C.

[0159] For example, the voltage applied to the metal wire is adjusted so that the temperature of the center portion of the unsintered PTFE molded body falls within the above range.

[0160] The heating is preferably performed so that the temperature of the outer periphery of the uncalcined PTFE molded body reaches a temperature lower than the first melting point of the PTFE.

[0161] The second dielectric waveguide preferably includes a dielectric B as a waveguide medium. In addition, the second dielectric waveguide is preferably a dielectric waveguide that utilizes the relative permittivity difference within the dielectric B to transmit high frequencies such as millimeter waves and submillimeter waves.

[0162] The shapes of the first and second dielectric waveguides are not particularly limited and may be shapes corresponding to the characteristics required of the dielectric waveguides, but are preferably linear (rod-like).

[0163] The cross-sectional shape of the first dielectric waveguide line may be a circle such as a perfect circle or an ellipse, a square such as a square or a rectangle, or an annular shape.

[0164] The first and second dielectric waveguides are preferably curved. Generally, electromagnetic waves are particularly likely to penetrate a curved dielectric waveguide, but electromagnetic waves are unlikely to penetrate the first and second dielectric waveguides even if they are curved.

[0165] The cross-sectional area of ​​the first and second dielectric waveguides is appropriately selected according to the frequency of the electromagnetic wave used. For example, when transmitting a high frequency of 28 GHz, it is preferably 2 to 10 mm. 2 , more preferably 5 to 9 mm 2 .

[0166] As the first and second dielectric waveguide lines, there can be cited cylindrical dielectric lines, tubular dielectric lines, image lines, island image lines, trap image lines, ridge waveguides, strip dielectric lines (strip dielectric lines), inverted strip lines (reverse strip lines), H-shaped waveguides, non-radioactive dielectric lines (NRD waveguides), etc.

[0167] As an example of the first dielectric waveguide line, Figure 1 is a schematic diagram of a cross-section of a dielectric waveguide including a core dielectric 1, a dielectric layer 2 having a lower relative permittivity than the core dielectric, a dielectric layer 3 having a lower relative permittivity than dielectric layer 2, and a protective layer 4 (jacket). The core dielectric 1, dielectric layer 2, and dielectric layer 3 correspond to the core dielectric A1, dielectric layer A2, and dielectric layer A3, respectively, in the first dielectric waveguide.

[0168] As an example of the second dielectric waveguide line, Figure 2Schematic diagram of a cross section of a dielectric waveguide including a dielectric 11 whose relative permittivity gradually decreases from the center toward the outside in the radial direction and a protective layer 12 (jacket) is shown in FIG. The dielectric 11 corresponds to the dielectric B in the second dielectric waveguide.

[0169] It should be noted that the configurations of the first and second dielectric waveguide lines are not limited to those shown in the drawings.

[0170] Example

[0171] Next, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to these examples.

[0172] Numerical values ​​in Examples were measured by the following methods.

[0173] Dielectric constant and dielectric loss tangent (tanδ)

[0174] The relative dielectric constant of the dielectric (layer) constituting the dielectric waveguide line is determined by calculation from the specific gravity of the dielectric (layer) using a relationship formula representing the correlation (linear relationship) between specific gravity and relative dielectric constant (25°C, 6 GHz).

[0175] The above-mentioned specific gravity is measured by a submerged weighing method (in accordance with JIS Z 8807).

[0176] The relationship formula used in the calculation is different according to the type of resin, but can be obtained based on the numerical data of more than two specific gravities and relative dielectric constants obtained in advance. As an example of numerical data, the numerical data of the specific gravity and relative dielectric constant of PTFE are shown in Table 1.

[0177] [Table 1]

[0178] proportion Relative dielectric constant 0.00 1.00 0.71 1.40 1.38 1.75 1.60 1.85 1.80 1.96 2.23 2.20

[0179] The dielectric loss tangent of the dielectric (layer) constituting the dielectric waveguide line was measured at 25°C and 6 GHz using a cavity resonator manufactured by Kanto Denshi Applied Development Co., Ltd., by cutting a 2.0 mm × 2.0 mm × 110 mm square rod-shaped sample from the dielectric to be measured.

[0180] Example 1

[0181] Production of inner layer circuits

[0182] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5 mm. This extrudate was heated in an electric furnace at 80°C for 30 minutes, and then in an electric furnace at 200°C for 10 minutes to evaporate the extrusion aid.

[0183] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace and slowly cooled at room temperature to produce the inner layer circuitry. The inner layer circuitry had a specific gravity of 2.060, a relative dielectric constant of 2.10, and a dielectric loss tangent of 0.00020.

[0184] Preparation of middle layer 1

[0185] A rolled, unfired, unstretched PTFE tape cut into 8 mm wide and 250 μm thick pieces was wrapped around the inner circuit in an S-twist pattern at 1 mm intervals to a thickness of 1 mm, forming Intermediate Layer 1. Intermediate Layer 1 has a specific gravity of 1.595, a relative dielectric constant of 1.85, and a dielectric loss tangent of 0.00007.

[0186] Preparation of middle layer 2

[0187] A 150μm thick, 8mm-wide, calendered, unstretched PTFE tape stretched 3 times was Z-twisted around intermediate layer 1 at 1mm intervals to form intermediate layer 2. Intermediate layer 2 had a specific gravity of 0.957, a relative dielectric constant of 1.51, and a dielectric loss tangent of 0.00004.

[0188] Production of the outer layer

[0189] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a tubular extrudate with an outer diameter of 15 mm and an inner diameter of 7.5 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0190] After evaporating the extrusion aid, the extrudate was placed in an electric furnace set at 300°C for 30 minutes and then stretched to 2.5 times its original length. This produced a stretched PTFE tube with a specific gravity of 0.657, a relative dielectric constant of 1.35, and a dielectric loss tangent of 0.00003. This tube was then placed over the outer surface of the intermediate layer 2 to form the outer layer, resulting in a dielectric waveguide circuit.

[0191] The dielectric waveguide obtained above was cut into a length of 600 mm, both ends were processed into a conical shape, and inserted into a conical horn antenna. The insertion loss at 60 GHz was measured using a network analyzer and found to be -0.18 dB / cm.

[0192] It should be noted that the smaller the absolute value of the insertion loss, the less the electromagnetic wave penetrates.

[0193] Example 2

[0194] Production of inner layer circuits

[0195] 410g of a hydrocarbon solvent was mixed with 2kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid and molded at 3MPa to produce a preform with a diameter of 49mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5mm. This extrudate was heated in an electric furnace at 80°C for 30 minutes, then at 200°C for 10 minutes, and then at 300°C for 30 minutes to evaporate the extrusion aid, resulting in the inner layer circuit. The inner layer circuit had a specific gravity of 1.595, a relative dielectric constant of 1.85, and a dielectric loss tangent of 0.00007.

[0196] Preparation of middle layer 1

[0197] A 150μm thick, 8mm-wide rolled, unstretched PTFE tape stretched 3 times was Z-twisted around the inner circuit at 1mm intervals to a thickness of 1mm, forming Intermediate Layer 1. Intermediate Layer 1 had a specific gravity of 0.957, a relative permittivity of 1.51, and a dielectric loss tangent of 0.00004.

[0198] Production of the outer layer

[0199] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a tubular extrudate with an outer diameter of 15 mm and an inner diameter of 7.5 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0200] After evaporating the extrusion aid, the tube was placed in an electric furnace set at 300°C for 30 minutes and then stretched to 2.5 times its length. This produced a stretched PTFE tube with a specific gravity of 0.657, a relative dielectric constant of 1.35, and a dielectric loss tangent of 0.00003. This tube was then placed over the outer surface of the intermediate layer 1 to form the outer layer, resulting in a dielectric waveguide circuit.

[0201] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a conical shape. Both ends were inserted into a circular waveguide tube, and the insertion loss at 60 GHz was measured using a network analyzer. The result was -0.17 dB / cm.

[0202] Example 3

[0203] Production of inner layer circuits

[0204] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a paste extruder to obtain a 3.5 mm x 7 mm square rod-shaped extrudate. This extrudate was heated in an electric furnace at 50°C for 30 minutes, then at 80°C for 30 minutes, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0205] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace at room temperature and allowed to cool slowly, yielding the inner-layer circuitry. The inner-layer circuitry had a specific gravity of 2.158, a relative dielectric constant of 2.15, and a dielectric loss tangent of 0.00010.

[0206] Preparation of middle layer 1

[0207] A rolled, unsintered, unstretched PTFE tape cut into 8 mm wide and 250 μm thick pieces was wrapped around the inner circuit in an S-twist pattern at 1 mm intervals to a thickness of 2 mm, forming Intermediate Layer 1. Intermediate Layer 1 has a specific gravity of 1.595, a relative dielectric constant of 1.85, and a dielectric loss tangent of 0.00007.

[0208] Preparation of middle layer 2

[0209] A 150μm thick, 8mm-wide, calendered, unstretched PTFE tape stretched 3 times was Z-twisted around intermediate layer 1 at 1mm intervals to a thickness of 2mm, forming intermediate layer 2. Intermediate layer 2 had a specific gravity of 0.957, a relative dielectric constant of 1.51, and a dielectric loss tangent of 0.00004.

[0210] Production of the outer layer

[0211] A rolled, unstretched PTFE tape stretched 5 times and cut into 8 mm wide and 100 μm thick pieces was wrapped around the intermediate layer 2 in an S-twist pattern at 1 mm intervals to a thickness of 1 mm, forming the outer layer. The outer layer had a specific gravity of 0.657, a relative dielectric constant of 1.35, and a dielectric loss tangent of 0.00003.

[0212] A heat shrink tube made of FEP is covered on the outside of the outer layer and heated with a hot air gun to shrink it to form a protective layer, thereby obtaining a dielectric waveguide circuit.

[0213] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a 1:2 quadrangular pyramid shape. The two ends were respectively inserted into the pyramid horn antenna, and the insertion loss at 28 GHz was measured using a network analyzer, and the result was -0.25 dB / cm.

[0214] Example 4

[0215] Production of inner layer circuits

[0216] 410g of a hydrocarbon solvent was mixed with 2kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid and molded at 3MPa to produce a preform with a diameter of 49mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid, resulting in an inner layer circuit. The inner layer circuit had a specific gravity of 2.158, a relative dielectric constant of 2.15, and a dielectric loss tangent of 0.00010.

[0217] Preparation of middle layer 1

[0218] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a tubular extrudate with an outer diameter of 6.5 mm and an inner diameter of 3.5 mm. The extrudate was heated in an electric furnace at 50°C for 1 hour, in an electric furnace at 80°C for 1 hour, and then in an electric furnace at 200°C for 10 minutes to evaporate the extrusion aid. This tube was covered on the outside of the inner layer circuit to form the intermediate layer 1. The intermediate layer 1 had a specific gravity of 1.80, a relative dielectric constant of 1.96, and a dielectric loss tangent of 0.00009.

[0219] Preparation of middle layer 2

[0220] Using the same method as for intermediate layer 1, a tubular extrudate with an outer diameter of 10 mm and an inner diameter of 6.5 mm was obtained. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid. This tube was placed in an electric furnace set at 300°C for 30 minutes and then stretched to 2.5 times its length, producing an extended PTFE tube with a specific gravity of 1.6, a relative dielectric constant of 1.85, and a dielectric loss tangent of 0.00007. This tube was placed over the outside of intermediate layer 1 to form intermediate layer 2.

[0221] Production of the outer layer

[0222] Using the same method as for intermediate layer 1, a tubular extrudate with an outer diameter of 18 mm and an inner diameter of 10 mm was obtained. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid. This tube was placed in an electric furnace set at 300°C for 30 minutes and then stretched to three times its length, producing a stretched PTFE tube with a specific gravity of 0.71, a relative dielectric constant of 1.4, and a dielectric loss tangent of 0.00003. This tube was placed on the outside of intermediate layer 2 to form the outer layer.

[0223] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a conical shape. Both ends were inserted into a circular waveguide tube, and the insertion loss at 60 GHz was measured using a network analyzer. The result was -0.17 dB / cm.

[0224] Example 5

[0225] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 9 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 100°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0226] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 340°C for 15 minutes to sinter the PTFE. The sintered PTFE rod was immediately placed in a room-temperature atmosphere to rapidly cool the surface, resulting in a dielectric waveguide with a gradually decreasing dielectric constant radially outward.

[0227] The dielectric waveguide line obtained above has a specific gravity of 2.23 and a relative dielectric constant of 2.20 at the center, a specific gravity of 2.17 and a relative dielectric constant of 2.08 at a radial distance of about 2.3 mm from the center, and a specific gravity of 2.10 and a relative dielectric constant of 1.95 at the periphery.

[0228] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a conical shape. Both ends were inserted into a circular waveguide tube, and the insertion loss at 60 GHz was measured using a network analyzer. The result was -0.19 dB / cm.

[0229] Example 6

[0230] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid and molded at 3 MPa to produce a preform with a diameter of 49 mm and an inner diameter of 16 mm. This preform was extruded onto a 0.511 mm silver-plated copper wire using a PTFE paste extruder, resulting in a coated extrudate with a diameter of 9.0 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0231] The extrudate, after evaporation of the extrusion aid, was cut into 2-meter lengths. A DC power supply was connected to both ends of a silver-plated copper wire and 7.5 V was applied, resulting in a current of 15 A. The voltage application was stopped when the surface of the extrudate reached 250°C, and the extrudate was cooled to room temperature. The silver-plated wire was then removed, yielding a dielectric waveguide circuit.

[0232] The specific gravity of the dielectric waveguide line obtained above near the center (the part where the copper wire is located) is 2.23 and the relative dielectric constant is 2.20, the specific gravity of the part about 2.3 mm radially from the center is 2.17 and the relative dielectric constant is 2.08, and the specific gravity of the peripheral part is 2.10 and the relative dielectric constant is 1.95.

[0233] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a conical shape. Both ends were inserted into a circular waveguide tube, and the insertion loss at 60 GHz was measured using a network analyzer, and the result was -0.20 dB / cm.

[0234] Example 7

[0235] Production of inner layer circuits

[0236] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5 mm. This extrudate was heated in an electric furnace at 80°C for 30 minutes, and then in an electric furnace at 200°C for 10 minutes to evaporate the extrusion aid.

[0237] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace at room temperature and allowed to cool slowly, yielding the inner-layer circuitry. The inner-layer circuitry had a specific gravity of 2.060, a relative permittivity of 2.10, and a dielectric loss tangent of 0.00020.

[0238] Preparation of middle layer 1

[0239] A polyethylene (PE) foamed tube was used to cover the inner circuit. The intermediate layer 1 had an inner diameter of 3.6 mm, an outer diameter of 10.5 mm, a specific gravity of 0.396, a relative dielectric constant of 1.56, and a dielectric loss tangent of 0.00003.

[0240] Production of the outer layer

[0241] A single layer of expanded PE sheet (9 mm thick, 10 mm wide) was wrapped around the intermediate layer 1 to form the outer layer, resulting in a dielectric waveguide. The outer layer had a specific gravity of 0.01569, a relative permittivity of 1.03, and a dielectric loss tangent of 0.00002.

[0242] The dielectric waveguide obtained above was cut into a length of 600 mm, both ends were processed into a conical shape, and inserted into a horn antenna. The insertion loss at 60 GHz was measured using a network analyzer and found to be -0.17 dB / cm.

[0243] Example 8

[0244] Production of inner layer circuits

[0245] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5 mm. This extrudate was heated in an electric furnace at 80°C for 30 minutes, and then in an electric furnace at 200°C for 10 minutes to evaporate the extrusion aid.

[0246] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace at room temperature and allowed to cool slowly, yielding the inner-layer circuitry. The inner-layer circuitry had a specific gravity of 2.060, a relative permittivity of 2.10, and a dielectric loss tangent of 0.00020.

[0247] Preparation of middle layer 1

[0248] A foamed PFA tube made from PFA was placed around the inner circuit. The intermediate layer 1 had an inner diameter of 3.6 mm, an outer diameter of 10.5 mm, a specific gravity of 1.2, a relative dielectric constant of 1.5, and a dielectric loss tangent of 0.0002.

[0249] Production of the outer layer

[0250] A PFA foam sheet (9 mm thick, 10 mm wide) was wrapped around the intermediate layer 1 to form the outer layer, creating a dielectric waveguide. The outer layer had a specific gravity of 1.0, a relative permittivity of 1.2, and a dielectric loss tangent of 0.00008.

[0251] Example 9

[0252] Production of inner layer circuits

[0253] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5 mm. This extrudate was heated in an electric furnace at 80°C for 30 minutes, and then in an electric furnace at 200°C for 10 minutes to evaporate the extrusion aid.

[0254] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace at room temperature and allowed to cool slowly, yielding the inner-layer circuitry. The inner-layer circuitry had a specific gravity of 2.060, a relative permittivity of 2.10, and a dielectric loss tangent of 0.00020.

[0255] Preparation of middle layer 1

[0256] The inner layer circuit was covered with a foamed FEP tube made of FEP. The intermediate layer 1 had an inner diameter of 3.6 mm, an outer diameter of 10.5 mm, a specific gravity of 1.1, a relative dielectric constant of 1.5, and a dielectric loss tangent of 0.0002.

[0257] Production of the outer layer

[0258] A dielectric waveguide circuit was obtained by wrapping a single layer of a foamed FEP sheet (9 mm thick, 10 mm wide) around the intermediate layer 1 to form the outer layer. The outer layer had a specific gravity of 1.0, a relative dielectric constant of 1.1, and a dielectric loss tangent of 0.00007.

[0259] Comparative Example 1

[0260] Production of inner layer circuits

[0261] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a round rod-shaped extrudate with a diameter of 3.5 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0262] After evaporating the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace and slowly cooled at room temperature to produce the inner layer circuitry. The inner layer circuitry had a specific gravity of 2.060, a relative dielectric constant of 2.10, and a dielectric loss tangent of 0.0002.

[0263] Production of the outer layer

[0264] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a tubular extrudate with an outer diameter of 15 mm and an inner diameter of 3.5 mm. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0265] The unfired PTFE tube was placed in an electric furnace at 300°C for 1 hour, further stretched to 2.5 times its length, and cooled to room temperature while maintaining its full length. This resulted in an outer layer tube with a specific gravity of 0.582, a relative dielectric constant of 1.31, and a dielectric loss tangent of 0.00003.

[0266] The outer layer tube is covered on the inner layer circuit as the outer layer.

[0267] A heat shrink tube made of FEP is covered on the outside of the outer layer and heated with a hot air gun to shrink it to form a protective layer, thereby obtaining a dielectric waveguide circuit.

[0268] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a conical shape. Both ends were inserted into a circular waveguide tube, and the insertion loss at 60 GHz was measured using a network analyzer, and the result was -0.21 dB / cm.

[0269] Comparative Example 2

[0270] Production of inner layer circuits

[0271] 410 g of a hydrocarbon solvent was mixed with 2 kg of PTFE fine powder (standard specific gravity (SSG): 2.175) as an extrusion aid, and the mixture was molded at 3 MPa to produce a preform with a diameter of 49 mm. This preform was paste-extruded using a PTFE paste extruder to obtain a 3.5 mm x 7 mm square rod-shaped extrudate. This extrudate was heated in an electric furnace at 50°C for 1 hour, then at 80°C for 1 hour, and then at 200°C for 10 minutes to evaporate the extrusion aid.

[0272] After evaporation of the extrusion aid, the extrudate was placed in an electric furnace heated to 360°C for 30 minutes to sinter the PTFE. The extrudate was then cooled to 200°C at a rate of 60°C / hr. The extrudate was then removed from the furnace and slowly cooled at room temperature to produce the inner-layer circuitry. The inner-layer circuitry had a specific gravity of 2.158, a relative dielectric constant of 2.15, and a dielectric loss tangent of 0.00010.

[0273] Production of the outer layer

[0274] A 100μm thick, 8mm-wide rolled, unsintered, unstretched PTFE tape was wrapped several times around the inner circuitry in an S-twist pattern at 1mm intervals to create a 5mm-thick outer layer. The outer layer has a specific gravity of 0.657, a relative dielectric constant of 1.35, and a dielectric loss tangent of 0.00003.

[0275] A heat shrink tube made of FEP was covered on the outside of the outer layer and heated with a hot air gun to shrink it to form a protective layer, thereby obtaining a dielectric waveguide circuit.

[0276] The dielectric waveguide line obtained above was cut into a length of 600 mm, and both ends were processed into a 1:2 quadrangular pyramid shape. The two ends were respectively inserted into the pyramid horn antenna, and the insertion loss at 28 GHz was measured using a network analyzer, and the result was -0.35 dB / cm.

Claims

1. A dielectric waveguide comprising a central dielectric A1, a dielectric layer A2 provided around the central dielectric A1, and a dielectric layer A3 provided around the dielectric layer A2, wherein: The central dielectric A1 comprises polytetrafluoroethylene, The relative dielectric constants of the central dielectric A1, dielectric layer A2, and dielectric layer A3 at 25°C and 6 GHz are expressed as ε A1 , ε A2 and ε A3 hour, ε A1 2.20 or less, ε A2 1.90 or less, ε A3 is less than 1.55, ε A1 >ε A2 >ε A3 , Ratio ε A2 / ε A1 is 0.65~0.95, which is higher than ε A3 / ε A2 0.65~0.95, The specific gravity of the dielectric layer A2 is smaller than that of the central dielectric A1 , and the specific gravity of the dielectric layer A3 is smaller than that of the dielectric layer A2 .

2. The dielectric waveguide circuit according to claim 1, wherein The dielectric loss tangent of the central dielectric A1, dielectric layer A2 and dielectric layer A3 at 25°C and 6 GHz is expressed as tanδ A1 tanδ A2 and tanδ A3 When tanδ A1 2.20×10 -4 Below, tanδ A2 1.20×10 -4 Below, tanδ A3 1.00×10 -4 the following.

3. The dielectric waveguide line according to claim 1 or 2, wherein: The dielectric layers A2 and A3 contain at least one resin A selected from the group consisting of polytetrafluoroethylene, tetrafluoroethylene / hexafluoropropylene copolymer, tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, and polyolefin.

4. The dielectric waveguide line according to claim 1 or 2, wherein: ε A1 It is 1.80 to 2.

15.

5. The dielectric waveguide line according to claim 1 or 2, wherein: ε A2 It is 1.50 to 1.

90.

6. The dielectric waveguide line according to claim 1 or 2, wherein: ε A3 It is 1.01~1.

45.

7. The dielectric waveguide line according to claim 1 or 2, wherein: The dielectric loss tangent of the central dielectric A1 at 25°C and 6 GHz is expressed as tanδ A1 When tanδ A1 0.50×10 -4 ~2.10×10 -4 .

8. The dielectric waveguide line according to claim 1 or 2, wherein: The dielectric loss tangent of dielectric layer A3 at 25°C and 6 GHz is expressed as tanδ A3 When tanδ A3 0.20×10 -4 ~0.80×10 -4 .

9. A dielectric waveguide line comprising a dielectric B comprising polytetrafluoroethylene, wherein: Dielectric B is seamlessly formed from the same material, and its relative dielectric constant at 25°C and 6 GHz decreases gradually and continuously in the radial direction toward the outside. The rate of decrease in relative dielectric constant is 0.005% or more and 20% or less per 1 mm toward the outside in the radial direction.

10. The dielectric waveguide line according to claim 9, wherein The relative dielectric constant of the central portion of the dielectric B is 2.10 to 2.

25.

11. The dielectric waveguide line according to claim 9 or 10, wherein: The relative dielectric constant of the outer peripheral portion of the dielectric B is 1.70 to 2.00.

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