WO2020065715A1 - Radar device - Google Patents

Radar device Download PDF

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Publication number
WO2020065715A1
WO2020065715A1 PCT/JP2018/035392 JP2018035392W WO2020065715A1 WO 2020065715 A1 WO2020065715 A1 WO 2020065715A1 JP 2018035392 W JP2018035392 W JP 2018035392W WO 2020065715 A1 WO2020065715 A1 WO 2020065715A1
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WO
WIPO (PCT)
Prior art keywords
fiber
reinforced plastic
fibers
radome
radar device
Prior art date
Application number
PCT/JP2018/035392
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French (fr)
Japanese (ja)
Inventor
亮太 関口
Original Assignee
三菱電機株式会社
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Publication date
Application filed by 三菱電機株式会社 filed Critical 三菱電機株式会社
Priority to PCT/JP2018/035392 priority Critical patent/WO2020065715A1/en
Priority to JP2019511791A priority patent/JPWO2020065715A1/en
Publication of WO2020065715A1 publication Critical patent/WO2020065715A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
    • G01S7/03—Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q1/00—Details of, or arrangements associated with, antennas
    • H01Q1/42—Housings not intimately mechanically associated with radiating elements, e.g. radome

Definitions

  • the present invention relates to a radar device.
  • Patent Document 1 discloses a radome having a so-called “sandwich structure”. More specifically, the radome (10) described in Patent Literature 1 has a structure in which one core layer (C) is provided between two skin layers (S1, S2) (Patent Literature). 1 etc.).
  • on-vehicle millimeter wave radar an on-vehicle radar device using so-called “millimeter wave” has been developed (hereinafter referred to as “on-vehicle millimeter wave radar”).
  • on-vehicle millimeter wave radar In a vehicle-mounted millimeter-wave radar radome, there is a demand for both improved transmission of millimeter waves and reduced weight and improved rigidity.
  • the thickness of each skin layer is set based on a predetermined mathematical formula (see Equation (1) and the like in Patent Document 1), and the thickness of the core layer is determined.
  • a predetermined mathematical formula see Equation (1) and the like in Patent Document 1
  • the thickness of the core layer is determined.
  • the transmission of radio waves such as millimeter waves is improved. That is, the invention described in Patent Document 1 is not for reducing the weight and improving the rigidity. For this reason, the invention described in Patent Literature 1 has a problem to be solved from the viewpoint of improving the transparency to radio waves such as millimeter waves and reducing the weight and improving the rigidity.
  • the radome described in Patent Document 1 is used for an in-vehicle millimeter-wave radar, the frequency of the millimeter wave is 30 GHz or more (hereinafter referred to as “GHz”), and the equation (2) in Patent Document 1 is used. ),
  • the thickness of the core layer may be set to 2.5 mm or less (hereinafter referred to as “mm”) or less. Since the core layer is thin as described above, when each skin layer is thinned (that is, when the value of n in Expression (1) of Patent Document 1 is reduced), the weight of the radome can be easily reduced, It is difficult to improve the rigidity of the radome.
  • the present invention has been made in order to solve the above-described problems, and in a radome of an in-vehicle radar device, it has been proposed to improve the transmission of millimeter waves and other radio waves, reduce weight, and improve rigidity. The purpose is to achieve both.
  • the radar device of the present invention includes an antenna that radiates radio waves, and a radome for the antenna, wherein the radome includes a plurality of first fiber bundles including a plurality of first fibers and a plurality of first fiber bundles including a plurality of second fibers. And a second fiber bundle of the present invention, wherein the fiber-reinforced plastic layer is provided such that the longitudinal direction of each of the first fiber bundles is along the direction orthogonal to the polarization direction of the antenna. And, the longitudinal direction of each of the second fiber bundles is provided so as to be parallel to the polarization direction, and the electric conductivity of each of the first fibers is higher than the electric conductivity of each of the second fibers. Things.
  • a radome of a radar device for use in a vehicle or the like since it is configured as described above, in a radome of a radar device for use in a vehicle or the like, it is possible to achieve both improvement in transparency to radio waves such as millimeter waves, reduction in weight, and improvement in rigidity. .
  • FIG. 2 is a front view illustrating a main part of the antenna for the radar device according to the first embodiment.
  • FIG. 2 is a front view showing a main part of a fiber-reinforced plastic layer included in the radome for the radar device according to the first embodiment.
  • FIG. 2B is a sectional view taken along line A-A ′ shown in FIG. 2A.
  • FIG. 2 is a front view showing a main part of the radar device according to the first embodiment.
  • FIG. 3B is a sectional view taken along line A-A ′ shown in FIG. 3A.
  • FIG. 4 is a characteristic diagram showing millimeter wave transmittance by a radome for a radar device according to the first embodiment;
  • FIG. 4 is a characteristic diagram showing millimeter wave transmittance by a radome for a radar device according to the first embodiment;
  • FIG. 4 is a front view showing a main part of another radar device according to the first embodiment.
  • FIG. 10 is a front view showing a main part of one of the two fiber-reinforced plastic layers of the radome for a radar device according to the second embodiment.
  • FIG. 6B is a sectional view taken along line A-A ′ shown in FIG. 6A.
  • FIG. 14 is a front view showing a main part of the other fiber-reinforced plastic layer of the two fiber-reinforced plastic layers included in the radome for the radar device according to the second embodiment.
  • FIG. 7B is a sectional view taken along the line A-A ′ shown in FIG. 7A.
  • FIG. 9 is a front view showing a main part of the radar device according to the second embodiment.
  • FIG. 8B is a sectional view taken along the line A-A ′ shown in FIG. 8A.
  • FIG. 9 is a characteristic diagram illustrating millimeter wave transmittance by a radome for
  • FIG. 1 is a front view showing a main part of an antenna for a radar device according to the first embodiment.
  • FIG. 2A is a front view showing a main part of a fiber-reinforced plastic layer included in the radome for the radar device according to the first embodiment.
  • FIG. 2B is a sectional view taken along line AA ′ shown in FIG. 2A.
  • FIG. 3A is a front view showing a main part of the radar device according to Embodiment 1.
  • FIG. 3B is a sectional view taken along line AA ′ shown in FIG. 3A.
  • the radar apparatus 100 according to the first embodiment will be described with reference to FIGS. That is, the radar device 100 is mounted on a vehicle (not shown).
  • 1 is an antenna.
  • the antenna 1 emits a radio wave having a predetermined frequency f (for example, 77 GHz), that is, a millimeter wave.
  • the antenna 1 receives the reflected radio wave when the radiated radio wave is reflected by an obstacle (not shown) outside the vehicle.
  • the control unit (not shown) measures the distance between the vehicle and the obstacle based on the difference value ⁇ f between the frequency f of the radio wave radiated by the antenna 1 and the frequency f ′ of the radio wave received by the antenna 1. is there.
  • the control unit is configured by, for example, an ECU (Electronic Control Unit).
  • the radio waves radiated by the antenna 1 and the radio waves radiated by the antenna 1 are collectively referred to as “radiated waves”.
  • the frequency f of the radio wave radiated by the antenna 1, that is, the frequency f of the radiation wave may be referred to as a “carrier frequency”.
  • the antenna 1 is constituted by, for example, a so-called “planar array antenna”.
  • a plurality of antenna elements 12 are arranged in a plane, that is, a two-dimensional array on the surface of a substrate 11.
  • the radiation direction (so-called “main beam direction”) of a main radio wave (so-called “main beam direction”) of the radiated waves is, for example, a direction orthogonal or substantially orthogonal to the plate surface of the substrate 11, that is, the Z axis in the drawing. It is set in the direction along.
  • MB indicates a region corresponding to the main beam, that is, a region through which the main beam passes.
  • the antenna 1 is a so-called “linearly polarized antenna”.
  • the polarization direction of the antenna 1 is set in a direction parallel or substantially parallel to the plate surface of the substrate 11, more specifically, in a direction along the Y axis in the drawing.
  • the radar device 100 has a radome 2 for the antenna 1.
  • the radome 2 is arranged to face the surface of the substrate 11. That is, the radome 2 is arranged to face the plurality of antenna elements 12.
  • the radome 2 will be described.
  • the radome 2 has a fiber-reinforced plastic layer 3.
  • the fiber reinforced plastic layer 3 is provided, for example, parallel or substantially parallel to the plate surface of the substrate 11.
  • the fiber-reinforced plastic layer 3 includes a plurality of fiber bundles (hereinafter, sometimes referred to as “first fiber bundles”) 4.
  • the fiber-reinforced plastic layer 3 includes another plurality of fiber bundles (hereinafter, also referred to as “second fiber bundles”) 5.
  • Each of the plurality of first fiber bundles 4 is formed by bundling a plurality of fibers (hereinafter sometimes referred to as “first fibers”) 6 in a thread shape.
  • first fibers hereinafter sometimes referred to as “first fibers”
  • Each of the plurality of second fiber bundles 5 is formed by bundling other plurality of fibers (hereinafter, sometimes referred to as “second fibers”) 7 in a thread shape.
  • the fiber-reinforced plastic layer 3 is manufactured by, for example, applying a liquid plastic to the woven fabric of the fiber bundles 4 and 5 and then curing the plastic. That is, the plurality of first fiber bundles 4 correspond to either the warp or the weft in the woven fabric, and the plurality of second fiber bundles 5 correspond to the warp or the weft in the woven fabric. It corresponds to one of the other.
  • the longitudinal direction of each of the plurality of first fiber bundles 4 hereinafter, referred to as “first longitudinal direction”
  • second longitudinal direction of each of the plurality of second fiber bundles 5 hereinafter, referred to as “second longitudinal direction”. are orthogonal or substantially orthogonal to each other.
  • a direction orthogonal or substantially orthogonal to the polarization direction of the antenna 1 is referred to as an "orthogonal direction".
  • a direction parallel or substantially parallel to the polarization direction of the antenna 1 is referred to as a "parallel direction”.
  • Each of the plurality of first fibers 6 is made of, for example, a carbon fiber, a metal fiber, a boron fiber, or a thin metal wire having a thickness of 100 micrometers (hereinafter, referred to as “ ⁇ m”) or less.
  • the thickness of each of the plurality of first fibers 6 is set to a value that is 1/10 or less of the wavelength of the radiation wave in vacuum.
  • each of the plurality of second fibers 7 is made of, for example, glass fiber or quartz fiber.
  • the electric conductivity of each of the plurality of first fibers 6 is higher than the electric conductivity of each of the plurality of second fibers 7, and the electric conductivity of each of the plurality of first fibers 6 is different.
  • the dielectric loss is larger than the dielectric loss due to each of the plurality of second fibers 7.
  • the relative permittivity ⁇ of the portion of the fiber reinforced plastic layer 3 excluding the first fiber 6 is about 2.0 to 6.0.
  • the thickness t of the fiber-reinforced plastic layer 3 is set to a value corresponding to an integral multiple of half the wavelength of the radiated wave in the portion of the fiber-reinforced plastic layer 3 excluding the first fibers 6, for example. More specifically, the thickness t is set to a value based on the following equation (2).
  • ⁇ 0 is the wavelength of the radiation wave in vacuum.
  • n is one or more arbitrary integers.
  • the main part of the radar device 100 is thus configured.
  • the transmittance T when a structure having a finite impedance transmits a radio wave is expressed as a vertical component T ⁇ with respect to the polarization direction of the radio wave and a parallel component T ⁇ with respect to the polarization direction of the radio wave.
  • T ⁇ structures having dimensions of predetermined wavelength order transmittance T ⁇ when transmitting a radio wave having the wavelength, T ⁇ is represented respectively by the following equations (3) and (4).
  • Z ⁇ is the equivalent impedance of the structure in a direction perpendicular to the polarization direction of the radio wave.
  • Z ⁇ is the equivalent impedance of the structure in a direction parallel to the polarization direction of the radio wave.
  • Expressions (3) and (4) are based on the description of Reference 1 below.
  • the thickness of each of the plurality of first fibers 6 is set to a value that is 1/10 or less of the wavelength of the radiation wave in vacuum.
  • the equivalent impedance Z ⁇ the first fiber 6 becomes Z ⁇ >> 1 . Therefore, the transmittance T ⁇ ⁇ ⁇ ⁇ of the first fiber 6 is T ⁇ ⁇ 1.
  • the equivalent impedance Z ⁇ of the second fiber 7 becomes a value of 1 / ⁇ times to the impedance of the vacuum. For this reason, the transmittance T ⁇ in the second fiber 7 is a value equivalent to a value calculated using the so-called “Fresnel equation”.
  • the fiber reinforced plastic layer 3 reduces the Fresnel loss. Growth can be avoided. That is, even though these materials are contained in the fiber-reinforced plastic layer 3, it is possible to avoid a decrease in the permeability to radio waves such as millimeter waves (in other words, the permeability to radio waves such as millimeter waves). Can be improved.).
  • the first fibers 6 using these materials can improve the rigidity and reduce the weight of the fiber-reinforced plastic layer 3 as compared with the conventional fiber-reinforced plastic layer.
  • the rigidity of the radome 2 can be improved and the weight can be reduced as compared with the conventional radome having the conventional fiber reinforced plastic layer.
  • the conventional fiber reinforced plastic layer is made of glass fiber reinforced plastic or quartz fiber reinforced plastic. That is, the conventional fiber reinforced plastic layer does not include the material (carbon fiber, metal fiber, boron fiber, metal fine wire, or the like) used for the first fiber 6 in the fiber reinforced plastic layer 3.
  • the transmittance T ⁇ in the first fiber 6 is T ⁇ ⁇ 1
  • a predetermined comprising a carrier frequency f e.g., 77 GHz
  • Millimeter wave transmittance in the frequency range can be improved.
  • ⁇ Characteristic line I in FIG. 4 indicates the millimeter wave transmittance of the radome 2. This millimeter-wave transmittance is calculated using Fresnel's equation. In the calculation of the millimeter wave transmittance, the dielectric loss is ignored, and the Fresnel loss is to be calculated. This is because the dielectric loss is smaller than the Fresnel loss.
  • the first fibers 6 are made of carbon fibers, and the second fibers 7 are made of glass fibers.
  • ⁇ 0 °.
  • a configuration example of the radome 2 according to the characteristic line I is referred to as a “first configuration example”.
  • the use of the radome 2 of the first configuration example can reduce the Fresnel loss in the frequency range of 74 to 80 GHz to 5% or less.
  • the angle ⁇ is not limited to 0 °. As long as it is within the range that satisfies the condition shown in Expression (1), ⁇ ⁇ 0 ° may be satisfied as shown in FIG.
  • Such Z ⁇ ', Z ⁇ ' loss of radio waves based on becomes one represented by a function of sin 2 theta. Therefore, from the viewpoint of reducing the loss to 5% or less, it is preferable that the angle ⁇ be set to a value within a range of ⁇ 13 °, that is, a value within a range that satisfies the condition shown in Expression (1).
  • each of the plurality of first fibers 6 may be coated.
  • the radiation wave is not limited to the millimeter wave, and the carrier frequency f is not limited to 77 GHz.
  • the antenna 1 may emit a radio wave having any frequency f as long as the frequency f is used for the radar device 100.
  • the antenna 1 may emit a so-called “microwave” or “submillimeter wave”.
  • the radar device 100 is not limited to a vehicle-mounted device, and the application of the radar device 100 is not limited to measuring the distance between a vehicle and an obstacle.
  • the radar device 100 may be used for radar for any purpose.
  • the radar device 100 includes the antenna 1 that radiates radio waves and the radome 2 for the antenna 1, and the radome 2 includes a plurality of first fibers 6 formed by a plurality of first fibers 6.
  • the fiber reinforced plastic layer 3 includes one fiber bundle 4 and a plurality of second fiber bundles 5 formed by a plurality of second fibers 7.
  • the longitudinal direction (that is, the first longitudinal direction) is provided so as to be along the direction orthogonal to the polarization direction of the antenna 1, and the longitudinal direction (that is, the second longitudinal direction) of each of the second fiber bundles 5 is polarized. It is provided so as to be parallel to the direction, and the electric conductivity of each first fiber 6 is higher than the electric conductivity of each second fiber 7.
  • the thickness t of the fiber-reinforced plastic layer 3 is set to a value corresponding to an integral multiple of a half wavelength of a radio wave. Since the thickness t is set to a value based on the equation (2), Fresnel loss in a predetermined frequency range including the carrier frequency f can be reduced.
  • the individual first fibers 6 are made of carbon fibers, metal fibers, boron fibers, or fine metal wires, and the individual second fibers 7 are made of glass fibers or quartz fibers.
  • the material of the first fiber 6 is not limited to carbon fiber or metal fiber, but may be boron fiber or metal fine wire.
  • each first fiber 6 is set to a value of 1/10 or less of the wavelength of the radio wave. As described above, by setting the thickness of each of the first fibers 6 to a sufficiently small value, generation of a current flowing through the first fibers 6 can be more reliably prevented.
  • FIG. 6A is a front view showing a main part of one fiber reinforced plastic layer of two fiber reinforced plastic layers included in a radome for a radar device according to Embodiment 2.
  • FIG. 6B is a sectional view taken along line AA ′ shown in FIG. 6A.
  • FIG. 7A is a front view illustrating a main part of the other fiber reinforced plastic layer of the two fiber reinforced plastic layers included in the radome for the radar device according to Embodiment 2.
  • FIG. 7B is a sectional view taken along line AA ′ shown in FIG. 7A.
  • FIG. 8A is a front view showing a main part of the radar device according to Embodiment 2.
  • FIG. 8B is a sectional view taken along line AA ′ shown in FIG.
  • Embodiment 2 A radar apparatus 100a according to Embodiment 2 will be described with reference to FIGS. 6 to 8, the same reference numerals are given to the same constituent members and the like as those shown in FIGS. 2 and 3, and the description will be omitted.
  • the radar device 100a has a radome 2a for the antenna 1.
  • the radome 2a has two fiber-reinforced plastic layers 3 arranged facing each other.
  • the radome 2a has a gap layer 8 formed between the two fiber-reinforced plastic layers 3.
  • Each of the two fiber-reinforced plastic layers 3 is provided, for example, in parallel or substantially parallel to the plate surface of the substrate 11.
  • Each of the two fiber-reinforced plastic layers 3 has the same structure as that described in the first embodiment.
  • fiber-reinforced plastic layer 3 1 One of the two fiber-reinforced plastic layer 3 are those containing a second fiber bundle 5 1 of a plurality of first fiber bundles 4 1 and a plurality of. First each of the fiber bundles 4 1 a plurality of is made by bundling a first fiber 6 1 a plurality of filamentous. Second, each of the fiber bundle 5 1 a plurality of is made by bundling a second fiber 7 1 a plurality of filamentous.
  • the first fiber bundle 4 1 of each of the longitudinal direction of the plurality of is provided along the perpendicular direction
  • a second fiber bundle of a plurality of 5 1 of each of the longitudinal is provided along the parallel direction.
  • angle ⁇ 1 between the first longitudinal direction and the direction orthogonal to the polarization direction of the antenna that is, the angle ⁇ 1 parallel to the second longitudinal direction and the polarization direction of the antenna 1.
  • angle theta 1 between the direction is set to satisfy the condition value as shown in formula (7). In the examples shown in FIGS. 6 and 8, ⁇ 1 is set to 0 °.
  • each of the fibers 61 a plurality of, for example, carbon fibers, metal fibers, is constituted by boron fibers or thin metal wires having the following thickness 100 [mu] m.
  • First fiber 6 1 of each of the thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave.
  • the second respective fibers 71 a plurality of, for example, is constituted by glass fibers or quartz fibers.
  • first fibers 61 of each of the electrical conductivity of the plurality of higher than the second fiber 7 1 of each of the electrical conductivity of the plurality of, and the first fiber 6 a plurality of 1 each dielectric loss due to the is larger than the dielectric loss of the second fiber 7 1 of each of the plurality of lines.
  • the dielectric constant epsilon 1 site i.e. site being constituted by the second fiber 71 and plastic, except the first fiber 6 1 of the fiber-reinforced plastic layer 3 1, at about 2.0-6.0 is there.
  • Thickness t 1 of the fiber-reinforced plastic layer 3 1 is, for example, is set to a value corresponding to a half wavelength of the radiation waves at a site other than the first fiber 6 1 of the fiber-reinforced plastic layer 3 1 . More specifically, the thickness t 1 is set to a value based on the following equation (8).
  • the other fiber-reinforced plastic layer 3 2 of the two fiber-reinforced plastic layer 3, is intended to include a plurality of first fiber bundles 4 2 and a plurality second fiber bundle of the 5 2.
  • First each of the fiber bundles 4 2 a plurality of is made by bundling a first fiber 6 2 a plurality of filamentous.
  • Second, each fiber bundle 5 second plurality of is made by bundling a second fiber 7 2 a plurality of filamentous.
  • the first fiber bundles 4 2 of each of the longitudinal direction of the plurality of (that is, the first longitudinal direction) is provided along the perpendicular direction, and a second fiber bundle of a plurality of 5 2 of each of the longitudinal direction (i.e. second longitudinal direction) is provided along the parallel direction.
  • the angle ⁇ 2 between the first longitudinal direction and the direction orthogonal to the polarization direction of the antenna that is, the angle ⁇ 2 parallel to the second longitudinal direction and the polarization direction of the antenna 1.
  • First respective fibers 6 2 a plurality of, for example, carbon fibers, metal fibers, is constituted by boron fibers or thin metal wires having the following thickness 100 [mu] m.
  • the first fiber 6 2 each thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave.
  • the second respective fiber 7 2 a plurality of, for example is constituted by glass fibers or quartz fibers.
  • first fibers 6 2 of each of the electrical conductivity of the plurality of higher than the second fiber 7 2 of each of the electrical conductivity of the plurality of, and the first fiber 6 a plurality of 2 each dielectric loss due to the is larger than the dielectric loss of the second fiber 7 2 of each of the plurality of lines.
  • the dielectric constant epsilon 2 of the site i.e., site configured by the second fiber 7 2 and plastic
  • the first fiber 6 2 of the fiber-reinforced plastic layer 3 2 of about 2.0-6.0 is there.
  • Thickness t 2 of the fiber-reinforced plastic layer 3 2 is, for example, is set to a value corresponding to a half wavelength of the radiation waves at a site other than the first fiber 6 2 of the fiber-reinforced plastic layer 3 2 . More specifically, the thickness t 2 is set to a value based on the following equation (10).
  • the gap layer 8 contains air.
  • the relative permittivity of air is about 1.0. That is, the dielectric constant of the gap layer 8 (about 1.0) is fiber-reinforced plastic layer 3 1, 3 first fiber 6 1 of 2, the dielectric constant of the portion except the 6 2 (2.0 to 6. 0).
  • the value is set to a value corresponding to an integral multiple of a half wavelength of the radiation wave in the gap layer 8. More specifically, the interval d is set to a value based on the following equation (11).
  • M is an integer of 1 or more.
  • ⁇ is a coefficient that satisfies the condition shown in the following equation (12).
  • the main part of the radar device 100a is configured.
  • the first fibers 61 of each of the thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave.
  • the second fibers 71 of the equivalent impedance Z ⁇ 1 has a value of 1 / ⁇ Ipushiron 1 times to the impedance of the vacuum. For this reason, the transmittance T
  • the first fiber 6 2 each thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave.
  • the equivalent impedance Z ⁇ 2 the first fiber 6 2 Z ⁇ the 2 >> 1. Therefore, the transmittance T ⁇ 2 in the first fiber 6 2 becomes T ⁇ 2 ⁇ 1.
  • the second fiber 7 2 equivalent impedance Z ⁇ 2 becomes 1 / ⁇ 2 times the values for the impedance of the vacuum. For this reason, the transmittance T
  • electrical conductivity is high dielectric loss material having a large, but more particularly used in the material 1 is first fiber 6, 6 2, such as carbon fiber or metal fiber
  • fiber-reinforced plastic layer 3 1, 3 2 increase in Fresnel losses due can be avoided.
  • fiber reinforced plastic layer 3 1, 3 2 it is possible to avoid a decrease in permeability to radio waves such as a millimeter-wave (in other words, such as a millimeter-wave It is possible to improve the transparency to radio waves.).
  • fiber-reinforced plastic layer 3 1, 3 low dielectric constant between 2 layers i.e. the gap layer 8 is provided, it is possible to further improve the permeability to radio waves such as a millimeter wave.
  • the first fiber 6 1, 6 2 using these materials that compared to conventional fiber-reinforced plastic layer, improved and weight reduction of the stiffness of the fiber-reinforced plastic layer 3 1, 3 2 it can.
  • the conventional fiber reinforced plastic layer is made of glass fiber reinforced plastic or quartz fiber reinforced plastic. That is, the conventional fiber-reinforced plastic layer, fiber-reinforced plastic layer 3 1, 3 first fiber 6 in 2 1, 6 2 in using its dependent material (carbon fiber, metal fiber, boron fiber or thin metal wires, etc.) It does not include.
  • the transmittance T ⁇ 1 in the first fiber 61 is T ⁇ 1 ⁇ 1
  • the transmittance T ⁇ 2 in the first fiber 6 2 is T ⁇ 2 ⁇ 1
  • the interval d is the formula ( By setting the value based on 11), it is possible to improve the millimeter wave transmittance in a predetermined frequency range including the carrier frequency f (for example, 77 GHz).
  • Characteristic line II in FIG. 9 shows the millimeter wave transmittance by the radome 2a. This millimeter-wave transmittance is calculated using Fresnel's equation. In the calculation of the millimeter wave transmittance, the dielectric loss is ignored, and the Fresnel loss is to be calculated.
  • the characteristic line I shown in FIG. 9 is the same as the characteristic line I shown in FIG. That is, the characteristic line I indicates the millimeter-wave transmittance of the radome 2.
  • the first fiber 6 1, 6 2 are constituted by a carbon fiber, and a second fiber 7 1, 7 2 is constituted by glass fibers.
  • second configuration example a configuration example of the radome 2a according to the characteristic line II is referred to as a “second configuration example”.
  • the Fresnel loss in the frequency range of 74 to 80 GHz can be reduced to 5% or less.
  • the Fresnel loss in the frequency range of 73 to 81 GHz can be reduced to 5% or less.
  • the angle theta 1 is not limited to 0 °. As long as it is within the range satisfying the condition shown in Expression (7), ⁇ 1 ⁇ 0 ° may be satisfied. Further, as described above, the angle theta 2 is not limited to 0 °. As long as the condition shown in Expression (9) is satisfied, ⁇ 2 ⁇ 0 ° may be satisfied.
  • the first of each of the fibers 61 of the plurality of may be those coated is made.
  • the first of each of the fibers 6 second plurality book may be one coat was made.
  • one or more support members (not shown) is provided between the fiber-reinforced plastic layer 3 1, 3 2, may be one gap layer 8 is formed.
  • the rigidity of the radome 2a can be further improved while reducing the weight of the radome 2a.
  • the radar apparatus 100a can employ various modifications similar to those described in the first embodiment, that is, various modifications similar to the radar apparatus 100.
  • radiation waves are not limited to millimeter waves.
  • the radar device 100a is not limited to a vehicle-mounted device.
  • the radome 2a includes two fiber-reinforced plastic layers 3 that are arranged to face each other and a gap layer 8 that is formed between the two fiber-reinforced plastic layers 3.
  • the distance d between the two fiber-reinforced plastic layers 3 is set to a value corresponding to an integral multiple of a half wavelength of a radio wave.
  • the gap layer 8) is provided, it is possible to further improve the permeability to radio waves such as a millimeter wave. Further, since the interval d is set to a value based on the equation (11), Fresnel loss in a predetermined frequency range including the carrier frequency f can be reduced.
  • the interval d is an interval with respect to the direction of radio wave emission from the antenna 1 (more specifically, the direction of the main beam).
  • the radiation wave (more specifically, the main beam) can pass through the radome 2a with the high transmittance as described above.
  • any combination of the embodiments, a modification of an arbitrary component of each embodiment, or an omission of an arbitrary component in each embodiment is possible within the scope of the invention. .
  • the radar device of the present invention can be used, for example, for an in-vehicle millimeter-wave radar.

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  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Details Of Aerials (AREA)
  • Radar Systems Or Details Thereof (AREA)

Abstract

This radar device (100) is provided with an antenna (1) that radiates radio waves, and a radome (2) for the antenna (1). The radome (2) has a fiber reinforced plastic layer (3) that includes a plurality of first fiber bundles (4) composed of a plurality of first fibers (6) and a plurality of second fiber bundles (5) composed of a plurality of second fibers (7). The fiber reinforced plastic layer (3) is provided so that: the longitudinal direction of each of the first fiber bundles (4) is aligned in a direction orthogonal to the direction of polarization of the antenna (1);the longitudinal direction of each of the second fiber bundles (5) is aligned in a direction parallel to the direction of polarization; and the electrical conductivity of each of the first fibers (6) is greater than the electrical conductivity of each of the second fibers (7).

Description

レーダ装置Radar equipment
　本発明は、レーダ装置に関する。 The present invention relates to a radar device.
　従来、レーダ装置において、アンテナ用のレドームが開発されている。例えば、特許文献１には、いわゆる「サンドイッチ構造」を有するレドームが開示されている。より具体的には、特許文献１記載のレドーム（１０）は、２個のスキン層（Ｓ１，Ｓ２）間に１個のコア層（Ｃ）が設けられた構造を有するものである（特許文献１の図１等参照）。 レ Conventionally, radomes for antennas have been developed for radar devices. For example, Patent Document 1 discloses a radome having a so-called “sandwich structure”. More specifically, the radome (10) described in Patent Literature 1 has a structure in which one core layer (C) is provided between two skin layers (S1, S2) (Patent Literature). 1 etc.).
特開２０１７－７９４４８号公報JP 2017-79448 A
　従来、いわゆる「ミリ波」を用いた車載用のレーダ装置が開発されている（以下「車載用ミリ波レーダ」という。）。車載用ミリ波レーダのレドームにおいては、ミリ波に対する透過性の向上と重量の低減及び剛性の向上との両立が求められている。 Conventionally, an on-vehicle radar device using so-called “millimeter wave” has been developed (hereinafter referred to as “on-vehicle millimeter wave radar”). In a vehicle-mounted millimeter-wave radar radome, there is a demand for both improved transmission of millimeter waves and reduced weight and improved rigidity.
　ここで、特許文献１記載の発明は、サンドイッチ構造を有するレドームにおいて、各スキン層の肉厚を所定の数式に基づき設定するとともに（特許文献１の式（１）等参照）、コア層の肉厚を他の所定の数式に基づき設定することにより（特許文献１の式（２）等参照）、ミリ波等の電波に対する透過性の向上を図るものである。すなわち、特許文献１記載の発明は、重量の低減及び剛性の向上を図るためのものではない。このため、特許文献１記載の発明は、ミリ波等の電波に対する透過性の向上と重量の低減及び剛性の向上との両立という観点において課題が残るものであった。 Here, in the invention described in Patent Document 1, in a radome having a sandwich structure, the thickness of each skin layer is set based on a predetermined mathematical formula (see Equation (1) and the like in Patent Document 1), and the thickness of the core layer is determined. By setting the thickness based on another predetermined mathematical formula (see formula (2) in Patent Document 1 and the like), the transmission of radio waves such as millimeter waves is improved. That is, the invention described in Patent Document 1 is not for reducing the weight and improving the rigidity. For this reason, the invention described in Patent Literature 1 has a problem to be solved from the viewpoint of improving the transparency to radio waves such as millimeter waves and reducing the weight and improving the rigidity.
　例えば、仮に特許文献１記載のレドームを車載用ミリ波レーダに用いた場合、ミリ波の周波数が３０ギガヘルツ（以下「ＧＨｚ」と記載する。）以上であることにより、特許文献１の式（２）に基づき、コア層の肉厚が２．５ミリメートル（以下「ｍｍ」と記載する。）以下に設定されることがある。このようにコア層が薄肉であるため、各スキン層を薄肉にした場合（すなわち特許文献１の式（１）におけるｎの値を小さくした場合）、レドームの重量の低減が容易となるものの、レドームの剛性の向上が困難となる。他方、各スキン層を厚肉にした場合（すなわち特許文献１の式（１）におけるｎの値を大きくした場合）、レドームの剛性の向上が容易となるものの、レドームの重量の低減が困難となる。 For example, if the radome described in Patent Document 1 is used for an in-vehicle millimeter-wave radar, the frequency of the millimeter wave is 30 GHz or more (hereinafter referred to as “GHz”), and the equation (2) in Patent Document 1 is used. ), The thickness of the core layer may be set to 2.5 mm or less (hereinafter referred to as “mm”) or less. Since the core layer is thin as described above, when each skin layer is thinned (that is, when the value of n in Expression (1) of Patent Document 1 is reduced), the weight of the radome can be easily reduced, It is difficult to improve the rigidity of the radome. On the other hand, when the thickness of each skin layer is increased (that is, when the value of n in equation (1) of Patent Document 1 is increased), the rigidity of the radome can be easily improved, but it is difficult to reduce the weight of the radome. Become.
　本発明は、上記のような課題を解決するためになされたものであり、車載用等のレーダ装置のレドームにおいて、ミリ波等の電波に対する透過性の向上と重量の低減及び剛性の向上との両立を図ることを目的とする。 The present invention has been made in order to solve the above-described problems, and in a radome of an in-vehicle radar device, it has been proposed to improve the transmission of millimeter waves and other radio waves, reduce weight, and improve rigidity. The purpose is to achieve both.
　本発明のレーダ装置は、電波を放射するアンテナと、アンテナ用のレドームと、を備え、レドームは、複数本の第１繊維による複数本の第１繊維束と、複数本の第２繊維による複数本の第２繊維束と、を含む繊維強化プラスチック層を有し、繊維強化プラスチック層は、個々の第１繊維束の長手方向がアンテナの偏波方向に対する直交方向に沿うように設けられており、かつ、個々の第２繊維束の長手方向が偏波方向に対する平行方向に沿うように設けられており、個々の第１繊維の電気伝導率が個々の第２繊維の電気伝導率よりも高いものである。 The radar device of the present invention includes an antenna that radiates radio waves, and a radome for the antenna, wherein the radome includes a plurality of first fiber bundles including a plurality of first fibers and a plurality of first fiber bundles including a plurality of second fibers. And a second fiber bundle of the present invention, wherein the fiber-reinforced plastic layer is provided such that the longitudinal direction of each of the first fiber bundles is along the direction orthogonal to the polarization direction of the antenna. And, the longitudinal direction of each of the second fiber bundles is provided so as to be parallel to the polarization direction, and the electric conductivity of each of the first fibers is higher than the electric conductivity of each of the second fibers. Things.
　本発明によれば、上記のように構成したので、車載用等のレーダ装置のレドームにおいて、ミリ波等の電波に対する透過性の向上と重量の低減及び剛性の向上との両立を図ることができる。 According to the present invention, since it is configured as described above, in a radome of a radar device for use in a vehicle or the like, it is possible to achieve both improvement in transparency to radio waves such as millimeter waves, reduction in weight, and improvement in rigidity. .
実施の形態１に係るレーダ装置用のアンテナの要部を示す正面図である。FIG. 2 is a front view illustrating a main part of the antenna for the radar device according to the first embodiment. 実施の形態１に係るレーダ装置用のレドームが有する繊維強化プラスチック層の要部を示す正面図である。FIG. 2 is a front view showing a main part of a fiber-reinforced plastic layer included in the radome for the radar device according to the first embodiment. 図２Ａに示すＡ－Ａ’線に沿う断面図である。FIG. 2B is a sectional view taken along line A-A ′ shown in FIG. 2A. 実施の形態１に係るレーダ装置の要部を示す正面図である。FIG. 2 is a front view showing a main part of the radar device according to the first embodiment. 図３Ａに示すＡ－Ａ’線に沿う断面図である。FIG. 3B is a sectional view taken along line A-A ′ shown in FIG. 3A. 実施の形態１に係るレーダ装置用のレドームによるミリ波透過率を示す特性図である。FIG. 4 is a characteristic diagram showing millimeter wave transmittance by a radome for a radar device according to the first embodiment; 実施の形態１に係る他のレーダ装置の要部を示す正面図である。FIG. 4 is a front view showing a main part of another radar device according to the first embodiment. 実施の形態２に係るレーダ装置用のレドームが有する２個の繊維強化プラスチック層のうちの一方の繊維強化プラスチック層の要部を示す正面図である。FIG. 10 is a front view showing a main part of one of the two fiber-reinforced plastic layers of the radome for a radar device according to the second embodiment. 図６Ａに示すＡ－Ａ’線に沿う断面図である。FIG. 6B is a sectional view taken along line A-A ′ shown in FIG. 6A. 実施の形態２に係るレーダ装置用のレドームが有する２個の繊維強化プラスチック層のうちの他方の繊維強化プラスチック層の要部を示す正面図である。FIG. 14 is a front view showing a main part of the other fiber-reinforced plastic layer of the two fiber-reinforced plastic layers included in the radome for the radar device according to the second embodiment. 図７Ａに示すＡ－Ａ’線に沿う断面図である。FIG. 7B is a sectional view taken along the line A-A ′ shown in FIG. 7A. 実施の形態２に係るレーダ装置の要部を示す正面図である。FIG. 9 is a front view showing a main part of the radar device according to the second embodiment. 図８Ａに示すＡ－Ａ’線に沿う断面図である。FIG. 8B is a sectional view taken along the line A-A ′ shown in FIG. 8A. 実施の形態２に係るレーダ装置用のレドームによるミリ波透過率を示す特性図である。FIG. 9 is a characteristic diagram illustrating millimeter wave transmittance by a radome for a radar device according to Embodiment 2.
　以下、この発明をより詳細に説明するために、この発明を実施するための形態について、添付の図面に従って説明する。 Hereafter, in order to explain this invention in greater detail, the preferred embodiments of the present invention will be described with reference to the accompanying drawings.
実施の形態１．
　図１は、実施の形態１に係るレーダ装置用のアンテナの要部を示す正面図である。図２Ａは、実施の形態１に係るレーダ装置用のレドームが有する繊維強化プラスチック層の要部を示す正面図である。図２Ｂは、図２Ａに示すＡ－Ａ’線に沿う断面図である。図３Ａは、実施の形態１に係るレーダ装置の要部を示す正面図である。図３Ｂは、図３Ａに示すＡ－Ａ’線に沿う断面図である。図１～図３を参照して、実施の形態１のレーダ装置１００について、車載用ミリ波レーダに用いた例を中心に説明する。すなわち、レーダ装置１００は車両（不図示）に搭載されている。 Embodiment 1 FIG.
FIG. 1 is a front view showing a main part of an antenna for a radar device according to the first embodiment. FIG. 2A is a front view showing a main part of a fiber-reinforced plastic layer included in the radome for the radar device according to the first embodiment. FIG. 2B is a sectional view taken along line AA ′ shown in FIG. 2A. FIG. 3A is a front view showing a main part of the radar device according to Embodiment 1. FIG. 3B is a sectional view taken along line AA ′ shown in FIG. 3A. The radar apparatus 100 according to the first embodiment will be described with reference to FIGS. That is, the radar device 100 is mounted on a vehicle (not shown).
　図中、１はアンテナである。アンテナ１は、所定の周波数ｆ（例えば７７ＧＨｚ）を有する電波、すなわちミリ波を放射するものである。アンテナ１は、当該放射された電波が車両外の障害物（不図示）により反射されたとき、当該反射された電波を受信するものである。制御部（不図示）は、アンテナ１により放射される電波の周波数ｆとアンテナ１により受信された電波の周波数ｆ’との差分値Δｆに基づき、車両と障害物間の距離を測定するものである。制御部は、例えば、ＥＣＵ（Ｅｌｅｃｔｒｏｎｉｃ　Ｃｏｎｔｒｏｌ　Ｕｎｉｔ）により構成されている。 中 In the figure, 1 is an antenna. The antenna 1 emits a radio wave having a predetermined frequency f (for example, 77 GHz), that is, a millimeter wave. The antenna 1 receives the reflected radio wave when the radiated radio wave is reflected by an obstacle (not shown) outside the vehicle. The control unit (not shown) measures the distance between the vehicle and the obstacle based on the difference value Δf between the frequency f of the radio wave radiated by the antenna 1 and the frequency f ′ of the radio wave received by the antenna 1. is there. The control unit is configured by, for example, an ECU (Electronic Control Unit).
　以下、アンテナ１により放射される電波及びアンテナ１により放射された電波を「放射波」と総称する。また、アンテナ１により放射される電波の周波数ｆ、すなわち放射波の周波数ｆを「キャリア周波数」ということがある。 Hereinafter, the radio waves radiated by the antenna 1 and the radio waves radiated by the antenna 1 are collectively referred to as “radiated waves”. Further, the frequency f of the radio wave radiated by the antenna 1, that is, the frequency f of the radiation wave may be referred to as a “carrier frequency”.
　アンテナ１は、例えば、いわゆる「平面アレーアンテナ」により構成されている。図１及び図３に示す例においては、基板１１の表面部に複数個のアンテナ素子１２が平面状に、すなわち二次元アレー状に配列されている。 The antenna 1 is constituted by, for example, a so-called “planar array antenna”. In the example shown in FIGS. 1 and 3, a plurality of antenna elements 12 are arranged in a plane, that is, a two-dimensional array on the surface of a substrate 11.
　放射波のうちの主要な電波（いわゆる「メインビーム」）の放射方向（いわゆる「メインビーム方向」）は、例えば、基板１１の板面に対して直交又は略直交する方向、すなわち図中Ｚ軸に沿う方向に設定されている。図中ＭＢは、メインビームに対応する領域、すなわちメインビームの通過対象となる領域を示している。 The radiation direction (so-called “main beam direction”) of a main radio wave (so-called “main beam direction”) of the radiated waves is, for example, a direction orthogonal or substantially orthogonal to the plate surface of the substrate 11, that is, the Z axis in the drawing. It is set in the direction along. In the figure, MB indicates a region corresponding to the main beam, that is, a region through which the main beam passes.
　また、アンテナ１は、いわゆる「直線偏波アンテナ」である。アンテナ１の偏波方向は、基板１１の板面に対して平行又は略平行な方向、より具体的には図中Ｙ軸に沿う方向に設定されている。 {Circle around (1)} The antenna 1 is a so-called “linearly polarized antenna”. The polarization direction of the antenna 1 is set in a direction parallel or substantially parallel to the plate surface of the substrate 11, more specifically, in a direction along the Y axis in the drawing.
　レーダ装置１００は、アンテナ１用のレドーム２を有している。レドーム２は、基板１１の表面部と対向配置されている。すなわち、レドーム２は、複数個のアンテナ素子１２と対向配置されている。以下、レドーム２について説明する。 The radar device 100 has a radome 2 for the antenna 1. The radome 2 is arranged to face the surface of the substrate 11. That is, the radome 2 is arranged to face the plurality of antenna elements 12. Hereinafter, the radome 2 will be described.
　図２及び図３に示す如く、レドーム２は繊維強化プラスチック層３を有している。繊維強化プラスチック層３は、例えば、基板１１の板面に対して平行又は略平行に設けられている。 レ As shown in FIGS. 2 and 3, the radome 2 has a fiber-reinforced plastic layer 3. The fiber reinforced plastic layer 3 is provided, for example, parallel or substantially parallel to the plate surface of the substrate 11.
　繊維強化プラスチック層３は、複数本の繊維束（以下「第１繊維束」ということがある。）４を含むものである。また、繊維強化プラスチック層３は、他の複数本の繊維束（以下「第２繊維束」ということがある。）５を含むものである。複数本の第１繊維束４の各々は、複数本の繊維（以下「第１繊維」ということがある。）６を糸状に束ねてなるものである。また、複数本の第２繊維束５の各々は、他の複数本の繊維（以下「第２繊維」ということがある。）７を糸状に束ねてなるものである。 The fiber-reinforced plastic layer 3 includes a plurality of fiber bundles (hereinafter, sometimes referred to as “first fiber bundles”) 4. The fiber-reinforced plastic layer 3 includes another plurality of fiber bundles (hereinafter, also referred to as “second fiber bundles”) 5. Each of the plurality of first fiber bundles 4 is formed by bundling a plurality of fibers (hereinafter sometimes referred to as “first fibers”) 6 in a thread shape. Each of the plurality of second fiber bundles 5 is formed by bundling other plurality of fibers (hereinafter, sometimes referred to as “second fibers”) 7 in a thread shape.
　繊維強化プラスチック層３は、例えば、これらの繊維束４，５による織布に液状のプラスチックを塗布した後、当該プラスチックを硬化させることにより製造されたものである。すなわち、複数本の第１繊維束４は当該織布における経糸又は緯糸のうちのいずれか一方に対応するものであり、複数本の第２繊維束５は当該織布における経糸又は緯糸のうちのいずれか他方に対応するものである。複数本の第１繊維束４の各々の長手方向（以下「第１長手方向」という。）と複数本の第２繊維束５の各々の長手方向（以下「第２長手方向」という。）とは、互いに直交又は略直交している。 The fiber-reinforced plastic layer 3 is manufactured by, for example, applying a liquid plastic to the woven fabric of the fiber bundles 4 and 5 and then curing the plastic. That is, the plurality of first fiber bundles 4 correspond to either the warp or the weft in the woven fabric, and the plurality of second fiber bundles 5 correspond to the warp or the weft in the woven fabric. It corresponds to one of the other. The longitudinal direction of each of the plurality of first fiber bundles 4 (hereinafter, referred to as “first longitudinal direction”) and the longitudinal direction of each of the plurality of second fiber bundles 5 (hereinafter, referred to as “second longitudinal direction”). Are orthogonal or substantially orthogonal to each other.
　以下、繊維強化プラスチック層３において、アンテナ１の偏波方向に対して直交又は略直交する方向を「直交方向」という。また、繊維強化プラスチック層３において、アンテナ１の偏波方向に対して平行又は略平行な方向を「平行方向」という。繊維強化プラスチック層３は、第１長手方向が直交方向に沿うように設けられており、かつ、第２長手方向が平行方向に沿うように設けられている。より具体的には、第１長手方向と当該偏波方向に対して直交する方向との間の角度θ、すなわち第２長手方向と当該偏波方向に対して平行な方向との間の角度θが、以下の式（１）に示す条件を満たす値に設定されている。なお、図２及び図３に示す例においては、θ＝０°に設定されている。 Hereinafter, in the fiber reinforced plastic layer 3, a direction orthogonal or substantially orthogonal to the polarization direction of the antenna 1 is referred to as an "orthogonal direction". In the fiber reinforced plastic layer 3, a direction parallel or substantially parallel to the polarization direction of the antenna 1 is referred to as a "parallel direction". The fiber reinforced plastic layer 3 is provided so that the first longitudinal direction is along the orthogonal direction, and is provided such that the second longitudinal direction is along the parallel direction. More specifically, the angle θ between the first longitudinal direction and the direction orthogonal to the polarization direction, that is, the angle θ between the second longitudinal direction and the direction parallel to the polarization direction Is set to a value that satisfies the condition shown in the following equation (1). In the examples shown in FIGS. 2 and 3, θ = 0 ° is set.
　－１３°≦θ≦＋１３°　（１） -13 ° ≦ θ ≦ + 13 ° (1)
　複数本の第１繊維６の各々は、例えば、炭素繊維、金属繊維、ボロン繊維、又は１００マイクロメートル（以下「μｍ」と記載する。）以下の太さを有する金属細線により構成されている。複数本の第１繊維６の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これに対して、複数本の第２繊維７の各々は、例えば、ガラス繊維又はクオーツ繊維により構成されている。 Each of the plurality of first fibers 6 is made of, for example, a carbon fiber, a metal fiber, a boron fiber, or a thin metal wire having a thickness of 100 micrometers (hereinafter, referred to as “μm”) or less. The thickness of each of the plurality of first fibers 6 is set to a value that is 1/10 or less of the wavelength of the radiation wave in vacuum. On the other hand, each of the plurality of second fibers 7 is made of, for example, glass fiber or quartz fiber.
　すなわち、複数本の第１繊維６の各々の電気伝導率が複数本の第２繊維７の各々の電気伝導率に比して高いものであり、かつ、複数本の第１繊維６の各々による誘電損失が複数本の第２繊維７の各々による誘電損失に比して大きいものである。繊維強化プラスチック層３のうちの第１繊維６を除く部位（すなわち第２繊維７及びプラスチックにより構成されている部位）の比誘電率εは、２．０～６．０程度である。 That is, the electric conductivity of each of the plurality of first fibers 6 is higher than the electric conductivity of each of the plurality of second fibers 7, and the electric conductivity of each of the plurality of first fibers 6 is different. The dielectric loss is larger than the dielectric loss due to each of the plurality of second fibers 7. The relative permittivity ε of the portion of the fiber reinforced plastic layer 3 excluding the first fiber 6 (that is, the portion composed of the second fiber 7 and the plastic) is about 2.0 to 6.0.
　繊維強化プラスチック層３の肉厚ｔは、例えば、繊維強化プラスチック層３のうちの第１繊維６を除く部位における放射波の２分の１波長の整数倍に対応する値に設定されている。より具体的には、肉厚ｔは、以下の式（２）に基づく値に設定されている。 The thickness t of the fiber-reinforced plastic layer 3 is set to a value corresponding to an integral multiple of half the wavelength of the radiated wave in the portion of the fiber-reinforced plastic layer 3 excluding the first fibers 6, for example. More specifically, the thickness t is set to a value based on the following equation (2).
　ｔ＝（ｎ×λ０）／（２×√ε）　（２） t = (n × λ 0 ) / (2 × √ε) (2)
　λ０は、真空中における放射波の波長である。ｎは、１以上の任意の整数である。 λ 0 is the wavelength of the radiation wave in vacuum. n is one or more arbitrary integers.
　このようにして、レーダ装置１００の要部が構成されている。 要 The main part of the radar device 100 is thus configured.
　次に、レーダ装置１００において、レドーム２を用いたことによる効果について説明する。 Next, the effect of using the radome 2 in the radar device 100 will be described.
　一般に、有限のインピーダンスを有する構造物が電波を透過させるときの透過率Ｔは、当該電波の偏波方向に対する垂直成分Ｔ⊥と当該電波の偏波方向に対する平行成分Ｔ∥とに分けて表される。例えば、所定の波長オーダーの寸法を有する構造物が当該波長を有する電波を透過させるときの透過率Ｔ⊥，Ｔ∥は、以下の式（３）及び式（４）によりそれぞれ表される。 Generally, the transmittance T when a structure having a finite impedance transmits a radio wave is expressed as a vertical component T ⊥ with respect to the polarization direction of the radio wave and a parallel component T ∥ with respect to the polarization direction of the radio wave. You. For example, structures having dimensions of predetermined wavelength order transmittance T ⊥ when transmitting a radio wave having the wavelength, T ∥ is represented respectively by the following equations (3) and (4).
　Ｔ⊥＝（４×Ｚ⊥ ２）／（１＋４×Ｚ⊥ ２）　（３）
　Ｔ∥＝（４×Ｚ∥ ２）／（１＋４×Ｚ∥ ２）　（４） T ⊥ = (4 × Z ⊥ 2) / (1 + 4 × Z ⊥ 2) (3)
T ∥ = (4 × Z ∥ 2) / (1 + 4 × Z ∥ 2) (4)
　Ｚ⊥は、当該電波の偏波方向に対して垂直な方向における当該構造物の等価インピーダンスである。Ｚ∥は、当該電波の偏波方向に対して平行な方向における当該構造物の等価インピーダンスである。なお、式（３）及び式（４）は、以下の参考文献１の記載に基づくものである。 Z⊥ is the equivalent impedance of the structure in a direction perpendicular to the polarization direction of the radio wave. Z∥ is the equivalent impedance of the structure in a direction parallel to the polarization direction of the radio wave. Expressions (3) and (4) are based on the description of Reference 1 below.
［参考文献１］
J. P. Auton, Appl. Opt., Vol.6, 1023 (1967) [Reference 1]
J. P. Auton, Appl. Opt., Vol. 6, 1023 (1967)
　ここで、上記のとおり、複数本の第１繊維６の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これにより、第１繊維６に流れる電流（すなわち繊維強化プラスチック層３において第１長手方向に沿うように流れる電流）が発生しないため、第１繊維６の等価インピーダンスＺ⊥はＺ⊥≫１となる。したがって、第１繊維６における透過率Ｔ⊥はＴ⊥≒１となる。これに対して、第２繊維７の等価インピーダンスＺ∥は、真空中のインピーダンスに対する１／√ε倍の値となる。このため、第２繊維７における透過率Ｔ∥は、いわゆる「フレネルの式」を用いて計算される値と同等の値となる。 Here, as described above, the thickness of each of the plurality of first fibers 6 is set to a value that is 1/10 or less of the wavelength of the radiation wave in vacuum. Thus, since the current flowing through the first fiber 6 (i.e. current in the fiber-reinforced plastic layer 3 flows along the first longitudinal direction) is not generated, the equivalent impedance Z ⊥ the first fiber 6 becomes Z ⊥ >> 1 . Therefore, the transmittance T におけ る of the first fiber 6 is T ⊥ ≒ 1. In contrast, the equivalent impedance Z ∥ of the second fiber 7 becomes a value of 1 / √ε times to the impedance of the vacuum. For this reason, the transmittance T ∥ in the second fiber 7 is a value equivalent to a value calculated using the so-called “Fresnel equation”.
　以上の原理により、電気伝導率が高く誘電損失が大きい材料、より具体的には炭素繊維又は金属繊維などの材料が第１繊維６に用いられているものの、繊維強化プラスチック層３によるフレネル損失の増大は回避することができる。すなわち、これらの材料が繊維強化プラスチック層３に含まれているにもかかわらず、ミリ波等の電波に対する透過性の低下を回避することができる（換言すれば、ミリ波等の電波に対する透過性の向上を図ることができる。）。 According to the above principle, although a material having a high electric conductivity and a large dielectric loss, more specifically, a material such as a carbon fiber or a metal fiber is used for the first fiber 6, the fiber reinforced plastic layer 3 reduces the Fresnel loss. Growth can be avoided. That is, even though these materials are contained in the fiber-reinforced plastic layer 3, it is possible to avoid a decrease in the permeability to radio waves such as millimeter waves (in other words, the permeability to radio waves such as millimeter waves). Can be improved.).
　また、これらの材料を用いた第１繊維６により、従来の繊維強化プラスチック層に比して、繊維強化プラスチック層３の剛性の向上及び重量の低減を図ることができる。この結果、当該従来の繊維強化プラスチック層を有する従来のレドームに比して、レドーム２の剛性の向上及び重量の低減を図ることができる。ここで、当該従来の繊維強化プラスチック層は、ガラス繊維強化プラスチック又はクオーツ繊維強化プラスチックなどにより構成されているものである。すなわち、当該従来の繊維強化プラスチック層は、繊維強化プラスチック層３における第１繊維６に用いられている材料（炭素繊維、金属繊維、ボロン繊維又は金属細線など）を含まないものである。 The first fibers 6 using these materials can improve the rigidity and reduce the weight of the fiber-reinforced plastic layer 3 as compared with the conventional fiber-reinforced plastic layer. As a result, the rigidity of the radome 2 can be improved and the weight can be reduced as compared with the conventional radome having the conventional fiber reinforced plastic layer. Here, the conventional fiber reinforced plastic layer is made of glass fiber reinforced plastic or quartz fiber reinforced plastic. That is, the conventional fiber reinforced plastic layer does not include the material (carbon fiber, metal fiber, boron fiber, metal fine wire, or the like) used for the first fiber 6 in the fiber reinforced plastic layer 3.
　さらに、第１繊維６における透過率Ｔ⊥がＴ⊥≒１であるため、肉厚ｔが式（２）に基づく値に設定されていることにより、キャリア周波数ｆ（例えば７７ＧＨｚ）を含む所定の周波数範囲におけるミリ波透過率を向上することができる。 Furthermore, since the transmittance T ⊥ in the first fiber 6 is T ⊥ ≒ 1, by the wall thickness t is set to a value according to equation (2), a predetermined comprising a carrier frequency f (e.g., 77 GHz) Millimeter wave transmittance in the frequency range can be improved.
　図４における特性線Ｉは、レドーム２によるミリ波透過率を示している。このミリ波透過率は、フレネルの式を用いて計算されたものである。なお、このミリ波透過率の計算において、誘電損失は無視しており、フレネル損失を計算の対象としている。これは、フレネル損失に比して誘電損失が小さいためである。 特性 Characteristic line I in FIG. 4 indicates the millimeter wave transmittance of the radome 2. This millimeter-wave transmittance is calculated using Fresnel's equation. In the calculation of the millimeter wave transmittance, the dielectric loss is ignored, and the Fresnel loss is to be calculated. This is because the dielectric loss is smaller than the Fresnel loss.
　特性線Ｉに係るレドーム２においては、第１繊維６が炭素繊維により構成されており、かつ、第２繊維７がガラス繊維により構成されている。特性線Ｉに係るレドーム２においては、θ＝０°である。特性線Ｉに係るレドーム２においては、繊維強化プラスチック層３のうちの第１繊維６を除く部位におけるアンテナ１の偏波方向に対する比誘電率が４．０である（すなわち、ε＝４．０である。）。特性線Ｉに係るレドーム２においては、肉厚ｔが１．９５ｍｍに設定されている（すなわち、ｆ＝７７ＧＨｚかつε＝４．０であるところ、ｎ＝２である。）。以下、特性線Ｉに係るレドーム２の構成例を「第１構成例」という。 レ In the radome 2 according to the characteristic line I, the first fibers 6 are made of carbon fibers, and the second fibers 7 are made of glass fibers. In the radome 2 according to the characteristic line I, θ = 0 °. In the radome 2 according to the characteristic line I, the relative permittivity with respect to the polarization direction of the antenna 1 in the portion of the fiber-reinforced plastic layer 3 excluding the first fiber 6 is 4.0 (that is, ε = 4.0). Is.). In the radome 2 according to the characteristic line I, the thickness t is set to 1.95 mm (that is, n = 2 where f = 77 GHz and ε = 4.0). Hereinafter, a configuration example of the radome 2 according to the characteristic line I is referred to as a “first configuration example”.
　図４に示す如く、第１構成例のレドーム２を用いることにより、７４～８０ＧＨｚの周波数範囲におけるフレネル損失を５％以下にすることができる。 (4) As shown in FIG. 4, the use of the radome 2 of the first configuration example can reduce the Fresnel loss in the frequency range of 74 to 80 GHz to 5% or less.
　なお、上記のとおり、角度θは０°に限定されるものではない。式（１）に示す条件を満たす範囲内であれば、図５に示す如くθ≠０°であっても良い。 As described above, the angle θ is not limited to 0 °. As long as it is within the range that satisfies the condition shown in Expression (1), θ ≠ 0 ° may be satisfied as shown in FIG.
　ただし、θ≠０°の場合における第１繊維６の等価インピーダンスＺ⊥’は、θ＝０°の場合における第１繊維６の等価インピーダンスＺ⊥に対して、以下の式（５）により表される。また、θ≠０°の場合における第２繊維７の等価インピーダンスＺ∥’は、θ＝０°の場合における第２繊維７の等価インピーダンスＺ∥に対して、以下の式（６）により表される。 However, the equivalent impedance Z⊥ ′ of the first fiber 6 when θ ≠ 0 ° is expressed by the following equation (5) with respect to the equivalent impedance Z⊥ of the first fiber 6 when θ = 0 °. You. The equivalent impedance Z∥ ′ of the second fiber 7 when θ ≠ 0 ° is expressed by the following equation (6) with respect to the equivalent impedance Z∥ of the second fiber 7 when θ = 0 °. You.
　Ｚ⊥’＝Ｚ⊥×ｃｏｓθ　（５）
　Ｚ∥’＝Ｚ∥×ｓｉｎθ　（６） Z⊥ '= Z⊥ × cosθ (5)
Z∥ '= Z∥ × sinθ (6)
　このようなＺ⊥’，Ｚ∥’に基づく電波の損失は、ｓｉｎ２θの関数により表されるものとなる。したがって、当該損失を５％以下にする観点から、角度θは±１３°の範囲内の値、すなわち式（１）に示す条件を満たす範囲内の値に設定するのが好適である。 Such Z ⊥ ', Z ∥' loss of radio waves based on becomes one represented by a function of sin 2 theta. Therefore, from the viewpoint of reducing the loss to 5% or less, it is preferable that the angle θ be set to a value within a range of ± 13 °, that is, a value within a range that satisfies the condition shown in Expression (1).
　また、複数本の第１繊維６の各々は、被覆がなされたものであっても良い。 Further, each of the plurality of first fibers 6 may be coated.
　また、放射波はミリ波に限定されるものではなく、キャリア周波数ｆは７７ＧＨｚに限定されるものではない。アンテナ１は、レーダ装置１００に用いられる周波数ｆであれば、如何なる周波数ｆを有する電波を放射するものであっても良い。例えば、アンテナ１は、いわゆる「マイクロ波」又は「サブミリ波」を放射するものであっても良い。 放射 Further, the radiation wave is not limited to the millimeter wave, and the carrier frequency f is not limited to 77 GHz. The antenna 1 may emit a radio wave having any frequency f as long as the frequency f is used for the radar device 100. For example, the antenna 1 may emit a so-called “microwave” or “submillimeter wave”.
　また、レーダ装置１００は車載用に限定されるものではなく、レーダ装置１００の用途は車両と障害物間の距離の測定に限定されるものではない。レーダ装置１００は、如何なる用途のレーダに用いられるものであっても良い。 The radar device 100 is not limited to a vehicle-mounted device, and the application of the radar device 100 is not limited to measuring the distance between a vehicle and an obstacle. The radar device 100 may be used for radar for any purpose.
　以上のように、実施の形態１のレーダ装置１００は、電波を放射するアンテナ１と、アンテナ１用のレドーム２と、を備え、レドーム２は、複数本の第１繊維６による複数本の第１繊維束４と、複数本の第２繊維７による複数本の第２繊維束５と、を含む繊維強化プラスチック層３を有し、繊維強化プラスチック層３は、個々の第１繊維束４の長手方向（すなわち第１長手方向）がアンテナ１の偏波方向に対する直交方向に沿うように設けられており、かつ、個々の第２繊維束５の長手方向（すなわち第２長手方向）が偏波方向に対する平行方向に沿うように設けられており、個々の第１繊維６の電気伝導率が個々の第２繊維７の電気伝導率よりも高い。これにより、炭素繊維又は金属繊維などの材料を第１繊維６に用いつつ、繊維強化プラスチック層３によるフレネル損失の増大を回避することができる。この結果、ミリ波等の電波に対する透過性の向上と重量の低減及び剛性の向上との両立を図ることができる。 As described above, the radar device 100 according to the first embodiment includes the antenna 1 that radiates radio waves and the radome 2 for the antenna 1, and the radome 2 includes a plurality of first fibers 6 formed by a plurality of first fibers 6. The fiber reinforced plastic layer 3 includes one fiber bundle 4 and a plurality of second fiber bundles 5 formed by a plurality of second fibers 7. The longitudinal direction (that is, the first longitudinal direction) is provided so as to be along the direction orthogonal to the polarization direction of the antenna 1, and the longitudinal direction (that is, the second longitudinal direction) of each of the second fiber bundles 5 is polarized. It is provided so as to be parallel to the direction, and the electric conductivity of each first fiber 6 is higher than the electric conductivity of each second fiber 7. This makes it possible to avoid an increase in Fresnel loss due to the fiber-reinforced plastic layer 3 while using a material such as carbon fiber or metal fiber for the first fiber 6. As a result, it is possible to achieve both improvement in the permeability to radio waves such as millimeter waves, reduction in weight, and improvement in rigidity.
　また、繊維強化プラスチック層３の肉厚ｔは、電波の２分の１波長の整数倍に対応する値に設定されている。肉厚ｔが式（２）に基づく値に設定されていることにより、キャリア周波数ｆを含む所定の周波数範囲におけるフレネル損失を低減することができる。 (4) The thickness t of the fiber-reinforced plastic layer 3 is set to a value corresponding to an integral multiple of a half wavelength of a radio wave. Since the thickness t is set to a value based on the equation (2), Fresnel loss in a predetermined frequency range including the carrier frequency f can be reduced.
　また、個々の第１繊維６は、炭素繊維、金属繊維、ボロン繊維又は金属細線により構成されており、個々の第２繊維７は、ガラス繊維又はクオーツ繊維により構成されている。このように、第１繊維６の材料は炭素繊維又は金属繊維に限定されるものではなく、ボロン繊維又は金属細線などを用いることもできる。 The individual first fibers 6 are made of carbon fibers, metal fibers, boron fibers, or fine metal wires, and the individual second fibers 7 are made of glass fibers or quartz fibers. As described above, the material of the first fiber 6 is not limited to carbon fiber or metal fiber, but may be boron fiber or metal fine wire.
　また、個々の第１繊維６の太さが電波の波長に対する１０分の１以下の値に設定されている。このように、個々の第１繊維６の太さを十分に小さい値に設定することにより、第１繊維６に流れる電流の発生をより確実に防ぐことができる。 (4) The thickness of each first fiber 6 is set to a value of 1/10 or less of the wavelength of the radio wave. As described above, by setting the thickness of each of the first fibers 6 to a sufficiently small value, generation of a current flowing through the first fibers 6 can be more reliably prevented.
実施の形態２．
　図６Ａは、実施の形態２に係るレーダ装置用のレドームが有する２個の繊維強化プラスチック層のうちの一方の繊維強化プラスチック層の要部を示す正面図である。図６Ｂは、図６Ａに示すＡ－Ａ’線に沿う断面図である。図７Ａは、実施の形態２に係るレーダ装置用のレドームが有する２個の繊維強化プラスチック層のうちの他方の繊維強化プラスチック層の要部を示す正面図である。図７Ｂは、図７Ａに示すＡ－Ａ’線に沿う断面図である。図８Ａは、実施の形態２に係るレーダ装置の要部を示す正面図である。図８Ｂは、図８Ａに示すＡ－Ａ’線に沿う断面図である。図６～図８を参照して、実施の形態２のレーダ装置１００ａについて説明する。なお、図６～図８において、図２～図３に示す構成部材等と同様の構成部材等には同一符号を付して説明を省略する。 Embodiment 2 FIG.
FIG. 6A is a front view showing a main part of one fiber reinforced plastic layer of two fiber reinforced plastic layers included in a radome for a radar device according to Embodiment 2. FIG. 6B is a sectional view taken along line AA ′ shown in FIG. 6A. FIG. 7A is a front view illustrating a main part of the other fiber reinforced plastic layer of the two fiber reinforced plastic layers included in the radome for the radar device according to Embodiment 2. FIG. 7B is a sectional view taken along line AA ′ shown in FIG. 7A. FIG. 8A is a front view showing a main part of the radar device according to Embodiment 2. FIG. 8B is a sectional view taken along line AA ′ shown in FIG. 8A. Embodiment 2 A radar apparatus 100a according to Embodiment 2 will be described with reference to FIGS. 6 to 8, the same reference numerals are given to the same constituent members and the like as those shown in FIGS. 2 and 3, and the description will be omitted.
　レーダ装置１００ａは、アンテナ１用のレドーム２ａを有している。レドーム２ａは、互いに対向配置された２個の繊維強化プラスチック層３を有している。また、レドーム２ａは、２個の繊維強化プラスチック層３間に形成された間隙層８を有している。２個の繊維強化プラスチック層３の各々は、例えば、基板１１の板面に対して平行又は略平行に設けられている。２個の繊維強化プラスチック層３の各々は、実施の形態１にて説明したものと同様の構造を有している。 The radar device 100a has a radome 2a for the antenna 1. The radome 2a has two fiber-reinforced plastic layers 3 arranged facing each other. The radome 2a has a gap layer 8 formed between the two fiber-reinforced plastic layers 3. Each of the two fiber-reinforced plastic layers 3 is provided, for example, in parallel or substantially parallel to the plate surface of the substrate 11. Each of the two fiber-reinforced plastic layers 3 has the same structure as that described in the first embodiment.
　すなわち、２個の繊維強化プラスチック層３のうちの一方の繊維強化プラスチック層３１は、複数本の第１繊維束４１及び複数本の第２繊維束５１を含むものである。複数本の第１繊維束４１の各々は、複数本の第１繊維６１を糸状に束ねてなるものである。複数本の第２繊維束５１の各々は、複数本の第２繊維７１を糸状に束ねてなるものである。 That is, fiber-reinforced plastic layer 3 1 One of the two fiber-reinforced plastic layer 3 are those containing a second fiber bundle 5 1 of a plurality of first fiber bundles 4 1 and a plurality of. First each of the fiber bundles 4 1 a plurality of is made by bundling a first fiber 6 1 a plurality of filamentous. Second, each of the fiber bundle 5 1 a plurality of is made by bundling a second fiber 7 1 a plurality of filamentous.
　繊維強化プラスチック層３１は、複数本の第１繊維束４１の各々の長手方向（すなわち第１長手方向）が直交方向に沿うように設けられており、かつ、複数本の第２繊維束５１の各々の長手方向（すなわち第２長手方向）が平行方向に沿うように設けられている。より具体的には、当該第１長手方向とアンテナ１の偏波方向に対して直交する方向との間の角度θ１、すなわち当該第２長手方向とアンテナ１の偏波方向に対して平行な方向との間の角度θ１が、以下の式（７）に示す条件を満たす値に設定されている。なお、図６及び図８に示す例においては、θ１＝０°に設定されている。 Fiber-reinforced plastic layer 3 1, the first fiber bundle 4 1 of each of the longitudinal direction of the plurality of (that is, the first longitudinal direction) is provided along the perpendicular direction, and a second fiber bundle of a plurality of 5 1 of each of the longitudinal (i.e. second longitudinal direction) is provided along the parallel direction. More specifically, the angle θ 1 between the first longitudinal direction and the direction orthogonal to the polarization direction of the antenna 1, that is, the angle θ 1 parallel to the second longitudinal direction and the polarization direction of the antenna 1. angle theta 1 between the direction is set to satisfy the condition value as shown in formula (7). In the examples shown in FIGS. 6 and 8, θ 1 is set to 0 °.
　－１３°≦θ１≦＋１３°　（７） −13 ° ≦ θ 1 ≦ + 13 ° (7)
　複数本の第１繊維６１の各々は、例えば、炭素繊維、金属繊維、ボロン繊維、又は１００μｍ以下の太さを有する金属細線により構成されている。複数本の第１繊維６１の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これに対して、複数本の第２繊維７１の各々は、例えば、ガラス繊維又はクオーツ繊維により構成されている。 First each of the fibers 61 a plurality of, for example, carbon fibers, metal fibers, is constituted by boron fibers or thin metal wires having the following thickness 100 [mu] m. First fiber 6 1 of each of the thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave. In contrast, the second respective fibers 71 a plurality of, for example, is constituted by glass fibers or quartz fibers.
　すなわち、複数本の第１繊維６１の各々の電気伝導率が複数本の第２繊維７１の各々の電気伝導率に比して高いものであり、かつ、複数本の第１繊維６１の各々による誘電損失が複数本の第２繊維７１の各々による誘電損失に比して大きいものである。繊維強化プラスチック層３１のうちの第１繊維６１を除く部位（すなわち第２繊維７１及びプラスチックにより構成されている部位）の比誘電率ε１は、２．０～６．０程度である。 That is, those first fibers 61 of each of the electrical conductivity of the plurality of higher than the second fiber 7 1 of each of the electrical conductivity of the plurality of, and the first fiber 6 a plurality of 1 each dielectric loss due to the is larger than the dielectric loss of the second fiber 7 1 of each of the plurality of lines. The dielectric constant epsilon 1 site (i.e. site being constituted by the second fiber 71 and plastic), except the first fiber 6 1 of the fiber-reinforced plastic layer 3 1, at about 2.0-6.0 is there.
　繊維強化プラスチック層３１の肉厚ｔ１は、例えば、繊維強化プラスチック層３１のうちの第１繊維６１を除く部位における放射波の２分の１波長に対応する値に設定されている。より具体的には、肉厚ｔ１は、以下の式（８）に基づく値に設定されている。 Thickness t 1 of the fiber-reinforced plastic layer 3 1 is, for example, is set to a value corresponding to a half wavelength of the radiation waves at a site other than the first fiber 6 1 of the fiber-reinforced plastic layer 3 1 . More specifically, the thickness t 1 is set to a value based on the following equation (8).
　ｔ１＝λ０／（２×√ε１）　（８） t 1 = λ 0 / (2 × √ε 1 ) (8)
　また、２個の繊維強化プラスチック層３のうちの他方の繊維強化プラスチック層３２は、複数本の第１繊維束４２及び複数本の第２繊維束５２を含むものである。複数本の第１繊維束４２の各々は、複数本の第１繊維６２を糸状に束ねてなるものである。複数本の第２繊維束５２の各々は、複数本の第２繊維７２を糸状に束ねてなるものである。 The other fiber-reinforced plastic layer 3 2 of the two fiber-reinforced plastic layer 3, is intended to include a plurality of first fiber bundles 4 2 and a plurality second fiber bundle of the 5 2. First each of the fiber bundles 4 2 a plurality of is made by bundling a first fiber 6 2 a plurality of filamentous. Second, each fiber bundle 5 second plurality of is made by bundling a second fiber 7 2 a plurality of filamentous.
　繊維強化プラスチック層３２は、複数本の第１繊維束４２の各々の長手方向（すなわち第１長手方向）が直交方向に沿うように設けられており、かつ、複数本の第２繊維束５２の各々の長手方向（すなわち第２長手方向）が平行方向に沿うように設けられている。より具体的には、当該第１長手方向とアンテナ１の偏波方向に対して直交する方向との間の角度θ２、すなわち当該第２長手方向とアンテナ１の偏波方向に対して平行な方向との間の角度θ２が、以下の式（９）に示す条件を満たす値に設定されている。なお、図７及び図８に示す例においては、θ２＝０°に設定されている。 Fiber-reinforced plastic layer 3 2, the first fiber bundles 4 2 of each of the longitudinal direction of the plurality of (that is, the first longitudinal direction) is provided along the perpendicular direction, and a second fiber bundle of a plurality of 5 2 of each of the longitudinal direction (i.e. second longitudinal direction) is provided along the parallel direction. More specifically, the angle θ 2 between the first longitudinal direction and the direction orthogonal to the polarization direction of the antenna 1, that is, the angle θ 2 parallel to the second longitudinal direction and the polarization direction of the antenna 1. angle theta 2 between the direction is set to satisfy the condition value as shown in formula (9). Note that, in the examples shown in FIGS. 7 and 8, θ 2 = 0 ° is set.
　－１３°≦θ２≦＋１３°　（９） −13 ° ≦ θ 2 ≦ + 13 ° (9)
　複数本の第１繊維６２の各々は、例えば、炭素繊維、金属繊維、ボロン繊維、又は１００μｍ以下の太さを有する金属細線により構成されている。複数本の第１繊維６２の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これに対して、複数本の第２繊維７２の各々は、例えば、ガラス繊維又はクオーツ繊維により構成されている。 First respective fibers 6 2 a plurality of, for example, carbon fibers, metal fibers, is constituted by boron fibers or thin metal wires having the following thickness 100 [mu] m. The first fiber 6 2 each thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave. In contrast, the second respective fiber 7 2 a plurality of, for example, is constituted by glass fibers or quartz fibers.
　すなわち、複数本の第１繊維６２の各々の電気伝導率が複数本の第２繊維７２の各々の電気伝導率に比して高いものであり、かつ、複数本の第１繊維６２の各々による誘電損失が複数本の第２繊維７２の各々による誘電損失に比して大きいものである。繊維強化プラスチック層３２のうちの第１繊維６２を除く部位（すなわち第２繊維７２及びプラスチックにより構成されている部位）の比誘電率ε２は、２．０～６．０程度である。 That is, those first fibers 6 2 of each of the electrical conductivity of the plurality of higher than the second fiber 7 2 of each of the electrical conductivity of the plurality of, and the first fiber 6 a plurality of 2 each dielectric loss due to the is larger than the dielectric loss of the second fiber 7 2 of each of the plurality of lines. The dielectric constant epsilon 2 of the site (i.e., site configured by the second fiber 7 2 and plastic), except the first fiber 6 2 of the fiber-reinforced plastic layer 3 2 of about 2.0-6.0 is there.
　繊維強化プラスチック層３２の肉厚ｔ２は、例えば、繊維強化プラスチック層３２のうちの第１繊維６２を除く部位における放射波の２分の１波長に対応する値に設定されている。より具体的には、肉厚ｔ２は、以下の式（１０）に基づく値に設定されている。 Thickness t 2 of the fiber-reinforced plastic layer 3 2 is, for example, is set to a value corresponding to a half wavelength of the radiation waves at a site other than the first fiber 6 2 of the fiber-reinforced plastic layer 3 2 . More specifically, the thickness t 2 is set to a value based on the following equation (10).
　ｔ２＝λ０／（２×√ε２）　（１０） t 2 = λ 0 / (2 × √ε 2 ) (10)
　間隙層８には空気が入っている。通常、空気の比誘電率は１．０程度である。すなわち、間隙層８の比誘電率（１．０程度）は繊維強化プラスチック層３１，３２のうちの第１繊維６１，６２を除く部位の比誘電率（２．０～６．０程度）よりも小さいものである。 The gap layer 8 contains air. Usually, the relative permittivity of air is about 1.0. That is, the dielectric constant of the gap layer 8 (about 1.0) is fiber-reinforced plastic layer 3 1, 3 first fiber 6 1 of 2, the dielectric constant of the portion except the 6 2 (2.0 to 6. 0).
　ここで、繊維強化プラスチック層３１，３２間の間隔ｄ、より具体的には繊維強化プラスチック層３１，３２の厚さ方向（すなわち図中Ｚ軸に沿う方向）に対する間隔ｄは、間隙層８における放射波の２分の１波長の整数倍に対応する値に設定されている。より具体的には、間隔ｄは、以下の式（１１）に基づく値に設定されている。 Here, fiber-reinforced plastic layer 3 1, 3 distance between 2 d, the distance d with respect to more specific fiber-reinforced plastic layer 3 1 to 3, 2 in the thickness direction (i.e. the direction along the Z axis in the figure), The value is set to a value corresponding to an integral multiple of a half wavelength of the radiation wave in the gap layer 8. More specifically, the interval d is set to a value based on the following equation (11).
　ｄ＝α×（ｍ×λ０／２）　（１１） d = α × (m × λ 0/2) (11)
　ｍは、１以上の任意の整数である。αは、以下の式（１２）に示す条件を満たす係数である。 M is an integer of 1 or more. α is a coefficient that satisfies the condition shown in the following equation (12).
　０．８≦α≦１．２　（１２） {0.8 ≦ α ≦ 1.2} (12)
　このようにして、レーダ装置１００ａの要部が構成されている。 要 Thus, the main part of the radar device 100a is configured.
　次に、レーダ装置１００ａにおいて、レドーム２ａを用いたことによる効果について説明する。 Next, the effect of using the radome 2a in the radar device 100a will be described.
　上記のとおり、複数本の第１繊維６１の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これにより、第１繊維６１に流れる電流（すなわち繊維強化プラスチック層３１において第１長手方向に沿うように流れる電流）が発生しないため、第１繊維６１の等価インピーダンスＺ⊥１はＺ⊥１≫１となる。したがって、第１繊維６１における透過率Ｔ⊥１はＴ⊥１≒１となる。これに対して、第２繊維７１の等価インピーダンスＺ∥１は、真空中のインピーダンスに対する１／√ε１倍の値となる。このため、第２繊維７１における透過率Ｔ∥１は、フレネルの式を用いて計算される値と同等の値となる。 As described above, the first fibers 61 of each of the thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave. Thus, since the current flowing through the first fiber 6 1 (that is, the current flowing along the first longitudinal direction in the fiber-reinforced plastic layer 3 1) is not generated, the first fiber 6 1 equivalent impedance Z ⊥1 the Z ⊥ It becomes 1 >> 1. Therefore, the transmittance T ⊥1 in the first fiber 61 becomes T ⊥1 ≒ 1. In contrast, the second fibers 71 of the equivalent impedance Z ∥1 has a value of 1 / √Ipushiron 1 times to the impedance of the vacuum. For this reason, the transmittance T || 1 in the second fiber 71 becomes a value equivalent to a value calculated using the Fresnel equation.
　また、複数本の第１繊維６２の各々の太さは、放射波の真空中の波長に対する１０分の１以下の値に設定されている。これにより、第１繊維６２に流れる電流（すなわち繊維強化プラスチック層３２において第１長手方向に沿うように流れる電流）が発生しないため、第１繊維６２の等価インピーダンスＺ⊥２はＺ⊥２≫１となる。したがって、第１繊維６２における透過率Ｔ⊥２はＴ⊥２≒１となる。これに対して、第２繊維７２の等価インピーダンスＺ∥２は、真空中のインピーダンスに対する１／√ε２倍の値となる。このため、第２繊維７２における透過率Ｔ∥２は、フレネルの式を用いて計算される値と同等の値となる。 The first fiber 6 2 each thickness of the plurality of is set to less than one-tenth with respect to the wavelength in vacuum of the radiation wave. Thus, since the current flowing through the first fiber 6 2 (that is, the current flowing as in the fiber-reinforced plastic layer 3 2 along the first longitudinal direction) is not generated, the equivalent impedance Z ⊥2 the first fiber 6 2 Z ⊥ the 2 >> 1. Therefore, the transmittance T ⊥2 in the first fiber 6 2 becomes T ⊥2 ≒ 1. In contrast, the second fiber 7 2 equivalent impedance Z ∥2 becomes 1 / √ε 2 times the values for the impedance of the vacuum. For this reason, the transmittance T || 2 of the second fiber 72 becomes a value equivalent to the value calculated using the Fresnel equation.
　以上の原理により、電気伝導率が高く誘電損失が大きい材料、より具体的には炭素繊維又は金属繊維などの材料が第１繊維６１，６２に用いられているものの、繊維強化プラスチック層３１，３２によるフレネル損失の増大は回避することができる。すなわち、これらの材料が繊維強化プラスチック層３１，３２に含まれているにもかかわらず、ミリ波等の電波に対する透過性の低下を回避することができる（換言すれば、ミリ波等の電波に対する透過性の向上を図ることができる。）。また、繊維強化プラスチック層３１，３２間に誘電率の低い層（すなわち間隙層８）が設けられていることにより、ミリ波等の電波に対する透過性を更に向上することができる。 By the above principle, electrical conductivity is high dielectric loss material having a large, but more particularly used in the material 1 is first fiber 6, 6 2, such as carbon fiber or metal fiber, fiber-reinforced plastic layer 3 1, 3 2 increase in Fresnel losses due can be avoided. In other words, despite these materials are contained in the fiber reinforced plastic layer 3 1, 3 2, it is possible to avoid a decrease in permeability to radio waves such as a millimeter-wave (in other words, such as a millimeter-wave It is possible to improve the transparency to radio waves.). Further, by fiber-reinforced plastic layer 3 1, 3 low dielectric constant between 2 layers (i.e. the gap layer 8) is provided, it is possible to further improve the permeability to radio waves such as a millimeter wave.
　また、これらの材料を用いた第１繊維６１，６２により、従来の繊維強化プラスチック層に比して、繊維強化プラスチック層３１，３２の剛性の向上及び重量の低減を図ることができる。この結果、当該従来の繊維強化プラスチック層を有する従来のレドームに比して、レドーム２ａの剛性の向上及び重量の低減を図ることができる。ここで、当該従来の繊維強化プラスチック層は、ガラス繊維強化プラスチック又はクオーツ繊維強化プラスチックなどにより構成されているものである。すなわち、当該従来の繊維強化プラスチック層は、繊維強化プラスチック層３１，３２における第１繊維６１，６２に用いられている材料（炭素繊維、金属繊維、ボロン繊維又は金属細線など）を含まないものである。 Further, the first fiber 6 1, 6 2 using these materials, that compared to conventional fiber-reinforced plastic layer, improved and weight reduction of the stiffness of the fiber-reinforced plastic layer 3 1, 3 2 it can. As a result, it is possible to improve the rigidity and reduce the weight of the radome 2a as compared with the conventional radome having the conventional fiber reinforced plastic layer. Here, the conventional fiber reinforced plastic layer is made of glass fiber reinforced plastic or quartz fiber reinforced plastic. That is, the conventional fiber-reinforced plastic layer, fiber-reinforced plastic layer 3 1, 3 first fiber 6 in 2 1, 6 2 in using its dependent material (carbon fiber, metal fiber, boron fiber or thin metal wires, etc.) It does not include.
　さらに、第１繊維６１における透過率Ｔ⊥１がＴ⊥１≒１であり、かつ、第１繊維６２における透過率Ｔ⊥２がＴ⊥２≒１であるため、間隔ｄが式（１１）に基づく値に設定されていることにより、キャリア周波数ｆ（例えば７７ＧＨｚ）を含む所定の周波数範囲におけるミリ波透過率を向上することができる。 Further, the transmittance T ⊥1 in the first fiber 61 is T ⊥1 ≒ 1, and, since the transmittance T ⊥2 in the first fiber 6 2 is T ⊥2 ≒ 1, the interval d is the formula ( By setting the value based on 11), it is possible to improve the millimeter wave transmittance in a predetermined frequency range including the carrier frequency f (for example, 77 GHz).
　図９における特性線ＩＩは、レドーム２ａによるミリ波透過率を示している。このミリ波透過率は、フレネルの式を用いて計算されたものである。なお、このミリ波透過率の計算において、誘電損失は無視しており、フレネル損失を計算の対象としている。また、図９に示す特性線Ｉは、図４に示す特性線Ｉと同一のものである。すなわち、特性線Ｉはレドーム２によるミリ波透過率を示している。 特性 Characteristic line II in FIG. 9 shows the millimeter wave transmittance by the radome 2a. This millimeter-wave transmittance is calculated using Fresnel's equation. In the calculation of the millimeter wave transmittance, the dielectric loss is ignored, and the Fresnel loss is to be calculated. The characteristic line I shown in FIG. 9 is the same as the characteristic line I shown in FIG. That is, the characteristic line I indicates the millimeter-wave transmittance of the radome 2.
　特性線ＩＩに係るレドーム２ａにおいては、第１繊維６１，６２が炭素繊維により構成されており、かつ、第２繊維７１，７２がガラス繊維により構成されている。特性線ＩＩに係るレドーム２ａにおいては、θ１＝θ２＝０°である。特性線ＩＩに係るレドーム２ａにおいては、繊維強化プラスチック層３１，３２のうちの第１繊維６１，６２を除く部位におけるアンテナ１の偏波方向に対する比誘電率が４．０である（すなわち、ε１＝ε２＝４．０である。）。特性線ＩＩに係るレドーム２ａにおいては、ｔ１＝ｔ２＝０．９７ｍｍに設定されている。特性線ＩＩに係るレドーム２ａにおいては、ｄ＝１．９５ｍｍに設定されている（すなわち、ｆ＝７７ＧＨｚであるところ、ｍ＝１かつα＝１．０である。）。以下、特性線ＩＩに係るレドーム２ａの構成例を「第２構成例」という。 In the radome 2a of the characteristic line II, the first fiber 6 1, 6 2 are constituted by a carbon fiber, and a second fiber 7 1, 7 2 is constituted by glass fibers. In the radome 2a according to the characteristic line II, θ 1 = θ 2 = 0 °. In the radome 2a of the characteristic line II, the dielectric constant with respect to the polarization direction of the antenna 1 at a site other than the first fiber 6 1, 6 2 of the fiber-reinforced plastic layer 3 1, 3 2 is a 4.0 (That is, ε 1 = ε 2 = 4.0.) In the radome 2a according to the characteristic line II, t 1 = t 2 = 0.97 mm is set. In the radome 2a according to the characteristic line II, d is set to 1.95 mm (that is, when f = 77 GHz, m = 1 and α = 1.0). Hereinafter, a configuration example of the radome 2a according to the characteristic line II is referred to as a “second configuration example”.
　図９に示す如く、第１構成例のレドーム２を用いることにより、７４～８０ＧＨｚの周波数範囲におけるフレネル損失を５％以下にすることができる。これに対して、第２構成例のレドーム２ａを用いることにより、７３～８１ＧＨｚの周波数範囲におけるフレネル損失を５％以下にすることができる。 As shown in FIG. 9, by using the radome 2 of the first configuration example, the Fresnel loss in the frequency range of 74 to 80 GHz can be reduced to 5% or less. On the other hand, by using the radome 2a of the second configuration example, the Fresnel loss in the frequency range of 73 to 81 GHz can be reduced to 5% or less.
　なお、α＝１．０である場合はもちろんのこと、式（１２）に示す条件を満たす範囲内であれば、α≠１．０であっても、キャリア周波数ｆを含む所定の周波数範囲におけるミリ波透過率の向上効果が得られるものである。これは、アンテナ１のメインビーム方向が繊維強化プラスチック層３１，３２の厚さ方向に沿う方向（すなわちＺ軸に沿う方向）に設定されている場合はもちろんのこと、当該メインビーム方向が当該厚さ方向に対して多少傾いた方向に設定されている場合であっても、当該周波数範囲におけるミリ波透過率の向上効果が得られることを示している。 It is to be noted that not only when α = 1.0, but also within a range satisfying the condition shown in the equation (12), even if α ≠ 1.0, in a predetermined frequency range including the carrier frequency f. The effect of improving the millimeter wave transmittance is obtained. This is true not only when the main beam direction of the antenna 1 is set in a direction along the thickness direction of the fiber-reinforced plastic layers 3 1 and 3 2 (that is, along the Z axis), but also when the main beam direction is set. This shows that the effect of improving the millimeter wave transmittance in the frequency range can be obtained even when the direction is set to be slightly inclined with respect to the thickness direction.
　また、上記のとおり、角度θ１は０°に限定されるものではない。式（７）に示す条件を満たす範囲内であれば、θ１≠０°であっても良い。また、上記のとおり、角度θ２は０°に限定されるものではない。式（９）に示す条件を満たす範囲内であれば、θ２≠０°であっても良い。 Further, as described above, the angle theta 1 is not limited to 0 °. As long as it is within the range satisfying the condition shown in Expression (7), θ 1 ≠ 0 ° may be satisfied. Further, as described above, the angle theta 2 is not limited to 0 °. As long as the condition shown in Expression (9) is satisfied, θ 2 ≠ 0 ° may be satisfied.
　また、複数本の第１繊維６１の各々は、被覆がなされたものであっても良い。また、複数本の第１繊維６２の各々は、被覆がなされたものであっても良い。 The first of each of the fibers 61 of the plurality of may be those coated is made. The first of each of the fibers 6 second plurality book may be one coat was made.
　また、繊維強化プラスチック層３１，３２間に１個以上の支持部材（不図示）が設けられていることにより、間隙層８が形成されているものであっても良い。これらの支持部材に適切な材料を用いることにより、レドーム２ａの重量の低減を図りつつ、レドーム２ａの剛性を更に向上することができる。 In addition, by one or more support members (not shown) is provided between the fiber-reinforced plastic layer 3 1, 3 2, may be one gap layer 8 is formed. By using an appropriate material for these support members, the rigidity of the radome 2a can be further improved while reducing the weight of the radome 2a.
　そのほか、レーダ装置１００ａは、実施の形態１にて説明したものと同様の種々の変形例、すなわちレーダ装置１００と同様の種々の変形例を採用することができる。例えば、放射波はミリ波に限定されるものではない。また、レーダ装置１００ａは車載用に限定されるものではない。 In addition, the radar apparatus 100a can employ various modifications similar to those described in the first embodiment, that is, various modifications similar to the radar apparatus 100. For example, radiation waves are not limited to millimeter waves. Further, the radar device 100a is not limited to a vehicle-mounted device.
　以上のように、実施の形態２のレーダ装置１００ａにおいて、レドーム２ａは、互いに対向配置された２個の繊維強化プラスチック層３と、２個の繊維強化プラスチック層３間に形成された間隙層８と、を有し、２個の繊維強化プラスチック層３間の間隔ｄは、電波の２分の１波長の整数倍に対応する値に設定されている。レドーム２ａを用いることにより、レドーム２を用いた場合と同様に、ミリ波等の電波に対する透過性の向上と重量の低減及び剛性の向上との両立を図ることができる。また、繊維強化プラスチック層３１，３２間に誘電率の低い層（すなわち間隙層８）が設けられていることにより、ミリ波等の電波に対する透過性を更に向上することができる。さらに、間隔ｄが式（１１）に基づく値に設定されていることにより、キャリア周波数ｆを含む所定の周波数範囲におけるフレネル損失を低減することができる。 As described above, in the radar apparatus 100a according to the second embodiment, the radome 2a includes two fiber-reinforced plastic layers 3 that are arranged to face each other and a gap layer 8 that is formed between the two fiber-reinforced plastic layers 3. The distance d between the two fiber-reinforced plastic layers 3 is set to a value corresponding to an integral multiple of a half wavelength of a radio wave. By using the radome 2a, as in the case of using the radome 2, it is possible to achieve both improvement in the permeability to radio waves such as millimeter waves, reduction in weight, and improvement in rigidity. Further, by fiber-reinforced plastic layer 3 1, 3 low dielectric constant between 2 layers (i.e. the gap layer 8) is provided, it is possible to further improve the permeability to radio waves such as a millimeter wave. Further, since the interval d is set to a value based on the equation (11), Fresnel loss in a predetermined frequency range including the carrier frequency f can be reduced.
　また、間隔ｄは、アンテナ１による電波の放射方向（より具体的にはメインビーム方向）に対する間隔である。これにより、放射波（より具体的にはメインビーム）が上記のような高い透過率にてレドーム２ａを通過することができる。 間隔 The interval d is an interval with respect to the direction of radio wave emission from the antenna 1 (more specifically, the direction of the main beam). Thereby, the radiation wave (more specifically, the main beam) can pass through the radome 2a with the high transmittance as described above.
　なお、本願発明はその発明の範囲内において、各実施の形態の自由な組み合わせ、あるいは各実施の形態の任意の構成要素の変形、もしくは各実施の形態において任意の構成要素の省略が可能である。 In the present invention, any combination of the embodiments, a modification of an arbitrary component of each embodiment, or an omission of an arbitrary component in each embodiment is possible within the scope of the invention. .
　本発明のレーダ装置は、例えば、車載用ミリ波レーダに用いることができる。 レ ー The radar device of the present invention can be used, for example, for an in-vehicle millimeter-wave radar.
　１　アンテナ、２，２ａ　レドーム、３　繊維強化プラスチック層、４　繊維束（第１繊維束）、５　繊維束（第２繊維束）、６　繊維（第１繊維）、７　繊維（第２繊維）、８　間隙層、１１　基板、１２　アンテナ素子、１００，１００ａ　レーダ装置。 1 antenna, 2, 2a radome, 3 fiber reinforced plastic layer, 4 fiber bundle (first fiber bundle), 5 fiber bundle (second fiber bundle), 6 fiber (first fiber), 7 fiber (second fiber), 8 gap layer, 11 substrate, 12 antenna element, 100, 100 radar device.

Claims (8)

  1. 　電波を放射するアンテナと、前記アンテナ用のレドームと、を備え、
    　前記レドームは、複数本の第１繊維による複数本の第１繊維束と、複数本の第２繊維による複数本の第２繊維束と、を含む繊維強化プラスチック層を有し、
    　前記繊維強化プラスチック層は、個々の前記第１繊維束の長手方向が前記アンテナの偏波方向に対する直交方向に沿うように設けられており、かつ、個々の前記第２繊維束の長手方向が前記偏波方向に対する平行方向に沿うように設けられており、
    　個々の前記第１繊維の電気伝導率が個々の前記第２繊維の電気伝導率よりも高い
    　ことを特徴とするレーダ装置。     An antenna that emits radio waves, and a radome for the antenna,
    The radome has a fiber-reinforced plastic layer including a plurality of first fiber bundles of a plurality of first fibers and a plurality of second fiber bundles of a plurality of second fibers.
    The fiber-reinforced plastic layer is provided such that the longitudinal direction of each of the first fiber bundles is along a direction orthogonal to the polarization direction of the antenna, and the longitudinal direction of each of the second fiber bundles is It is provided along the direction parallel to the polarization direction,
    The electrical conductivity of each said 1st fiber is higher than the electrical conductivity of each said 2nd fiber, The radar apparatus characterized by the above-mentioned.
  2. 　前記電波がミリ波であることを特徴とする請求項１記載のレーダ装置。 The radar device according to claim 1, wherein the radio wave is a millimeter wave.
  3. 　車載用であることを特徴とする請求項１記載のレーダ装置。 4. The radar device according to claim 1, wherein the radar device is used for a vehicle.
  4. 　前記レドームは、互いに対向配置された２個の前記繊維強化プラスチック層と、２個の前記繊維強化プラスチック層間に形成された間隙層と、を有し、
    　２個の前記繊維強化プラスチック層間の間隔は、前記電波の２分の１波長の整数倍に対応する値に設定されている
    　ことを特徴とする請求項１から請求項３のうちのいずれか１項記載のレーダ装置。     The radome has two fiber-reinforced plastic layers disposed to face each other, and a gap layer formed between the two fiber-reinforced plastic layers,
    The distance between two of the fiber-reinforced plastic layers is set to a value corresponding to an integral multiple of a half wavelength of the radio wave. The radar device according to the item.
  5. 　前記間隔は、前記アンテナによる前記電波の放射方向に対する前記間隔であることを特徴とする請求項４記載のレーダ装置。 5. The radar device according to claim 4, wherein the interval is the interval with respect to a radiation direction of the radio wave from the antenna.
  6. 　前記繊維強化プラスチック層の肉厚は、前記電波の２分の１波長の整数倍に対応する値に設定されていることを特徴する請求項１から請求項３のうちのいずれか１項記載のレーダ装置。 The thickness of the fiber reinforced plastic layer is set to a value corresponding to an integral multiple of a half wavelength of the radio wave, The thickness according to any one of claims 1 to 3, wherein Radar equipment.
  7. 　個々の前記第１繊維は、炭素繊維、金属繊維、ボロン繊維又は金属細線により構成されており、
    　個々の前記第２繊維は、ガラス繊維又はクオーツ繊維により構成されている
    　ことを特徴とする請求項１から請求項３のうちのいずれか１項記載のレーダ装置。     Each of the first fibers is made of carbon fiber, metal fiber, boron fiber or metal fine wire,
    4. The radar device according to claim 1, wherein each of the second fibers is made of glass fiber or quartz fiber. 5.
  8. 　個々の前記第１繊維の太さが前記電波の波長に対する１０分の１以下の値に設定されていることを特徴とする請求項１から請求項３のうちのいずれか１項記載のレーダ装置。 4. The radar device according to claim 1, wherein the thickness of each of the first fibers is set to a value equal to or less than one-tenth of a wavelength of the radio wave. 5. .
PCT/JP2018/035392 2018-09-25 2018-09-25 Radar device WO2020065715A1 (en)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5849498U (en) * 1981-09-28 1983-04-04 ティーディーケイ株式会社 radio wave reflector
JPS61149413U (en) * 1985-02-27 1986-09-16
US20040227687A1 (en) * 2003-05-15 2004-11-18 Delgado Heriberto Jose Passive magnetic radome
JP2006140956A (en) * 2004-11-15 2006-06-01 Anritsu Corp In-vehicle antenna
JP2008058130A (en) * 2006-08-31 2008-03-13 Hitachi Ltd In-vehicle radar
JP2012231286A (en) * 2011-04-26 2012-11-22 Electronic Navigation Research Institute Control method of linear polarization and apparatus therefor

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5849498U (en) * 1981-09-28 1983-04-04 ティーディーケイ株式会社 radio wave reflector
JPS61149413U (en) * 1985-02-27 1986-09-16
US20040227687A1 (en) * 2003-05-15 2004-11-18 Delgado Heriberto Jose Passive magnetic radome
JP2006140956A (en) * 2004-11-15 2006-06-01 Anritsu Corp In-vehicle antenna
JP2008058130A (en) * 2006-08-31 2008-03-13 Hitachi Ltd In-vehicle radar
JP2012231286A (en) * 2011-04-26 2012-11-22 Electronic Navigation Research Institute Control method of linear polarization and apparatus therefor

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