JP2010010962A - Glass antenna for vehicle and window glass plate for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low profile glass antenna for vehicles having wide band antenna characteristics which is suitable for reception of radiowaves such as terrestrial digital broadcast in a high frequency band. <P>SOLUTION: The glass antenna for vehicles includes: a first antenna element 1 formed by providing a window glass plate 12 for vehicles with an antenna conductor, a power supply part 8, a grounding conductor and a grounding part 7, and which extends in a first direction which is the one orthogonal to a horizontal direction starting from the power supply part 8; a second antenna element 2 which extends in a second direction which is the horizontal direction starting from the power supply part 8; a third antenna element which extends in a third direction which is the opposite direction of the second direction starting from an end point 1g to which the first antenna element 1 extends; a fourth antenna element 4 which extends in the third direction starting from the grounding part 7; and a fifth antenna element 5 which extends in the second direction starting from the end point 1g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a glass antenna for a vehicle in which an antenna conductor and a feeding portion are provided on a window glass plate for a vehicle. The present invention also relates to a vehicle window glass plate provided with the vehicle glass antenna.

Conventionally, as a glass antenna for a vehicle that receives digital terrestrial television broadcasting, an antenna conductor having a substantially U-shape is provided on a window glass plate, and a feeding point is provided at one of two end portions of the antenna conductor. (For example, refer to Patent Document 1).
JP 2006-270395 A

  However, in the above-described conventional technology, the configuration of the antenna conductor is simple and sufficient antenna gain cannot be obtained. Further, there is only one resonance frequency, and it is not possible to obtain an antenna gain having flatness that can cope with a wide band in the domestic digital terrestrial television broadcasting band. On the other hand, in a vehicle equipped with a window glass plate in which a glass antenna can be installed in a narrow range, it is often required to reduce the size of the antenna.

  Accordingly, the present invention provides a vehicle glass antenna having a low-profile and wide-band antenna characteristic suitable for receiving radio waves in a high frequency band such as terrestrial digital broadcasting, and a vehicle window glass plate including the vehicle glass antenna. With the goal.

In order to achieve the above object, a glass antenna for a vehicle according to the present invention is a glass antenna for a vehicle in which an antenna conductor and a power feeding portion are provided on a window glass plate for a vehicle, and the antenna conductor includes:
A first antenna element extending in a first direction that is perpendicular or substantially perpendicular to a horizontal direction from the power supply unit, and a first connection extending from the power supply unit or from the power supply unit A second antenna element extending in a second direction that is a horizontal or substantially horizontal direction via a conductor, and the second direction starting from an end point or a vicinity of the end point where the first antenna element extends. And a third antenna element extending in a third direction that is the opposite direction.

  Here, the glass antenna for a vehicle is provided with a ground conductor and a ground portion, the ground portion is provided in the vicinity of the power feeding portion, and the ground conductor starts from the ground portion or the ground portion. It is preferable that a fourth antenna element that extends in the third direction is provided via a second connection conductor that extends from.

  In addition, it is preferable that the antenna conductor includes a fifth antenna element extending in the second direction starting from the end point or the vicinity of the end point where the first antenna element extends.

  The antenna conductor includes a first antenna element group including a plurality of antenna elements extending in the third direction starting from at least one of the first antenna element and the power feeding unit, The third antenna element may be included in the first antenna element group.

  The antenna conductor includes a second antenna element group including a plurality of antenna elements extending in the second direction, starting from at least one of the power feeding unit and the first connection conductor, The second antenna element may be included in the second antenna element group.

  The ground conductor includes a third antenna element group including a plurality of antenna elements extending in the third direction starting from at least one of the ground portion and the second connection conductor, The fourth antenna element may be included in the third antenna element group.

  The antenna conductor includes a fourth antenna element group including a plurality of antenna elements extending in the second direction starting from the first antenna element, and the fifth antenna element includes: It may be included in the fourth antenna element group.

  According to the present invention, it is possible to obtain broadband antenna characteristics suitable for receiving radio waves in a high frequency band such as terrestrial digital television broadcasting while reducing the height of the antenna itself.

  The best mode for carrying out the present invention will be described below with reference to the drawings. Note that in the drawings for describing the embodiments, the directions on the drawings are used unless otherwise specified. In addition, these drawings are views of the interior of the vehicle (or the exterior of the vehicle) with the window glass plate attached to the vehicle. For example, when the window glass plate is a rear window glass plate attached to the rear portion of the vehicle, the left-right direction on the drawing corresponds to the vehicle width direction. In addition, this invention is not limited to a rear window glass plate, A windshield and a side window glass plate may be sufficient.

  FIG. 1 is a plan view of a glass antenna 100 for a vehicle that is an embodiment of the present invention. The glass antenna 100 for vehicles is a glass antenna for vehicles which provided the antenna conductor and the electric power feeding part in the window glass plate 12 for vehicles. Reference numeral 8 denotes a power feeding unit. On the drawing, the vehicle glass antenna 100 is separated from the edge 13 of the window glass plate 12 that is perpendicular to or substantially perpendicular to the horizontal direction as the first direction, starting from the power supply unit 8, and closest to the power supply unit 8. The horizontal direction, which is the second direction, starting from the antenna element 1, which is the first antenna element extending downward in the direction of, and the first connecting conductor (not shown) extending from the feeder 8 or the feeder 8 The antenna element 2 is a second antenna element that extends in the right direction in the direction of the drawing, and is opposite to the second direction by 180 ° from the end point 1g or the vicinity of the end point where the antenna element 1 extends. In this structure, the antenna element is an antenna element 3 that is a third antenna element that extends in the left direction in the drawing direction, which is the third direction.

  The glass antenna 100 for vehicles is a monopole antenna, and the reception signal in the electric power feeding part 8 is transmitted to a receiver (not shown). In the case of a monopole antenna, if the vehicle body opening to which the window glass plate 12 is attached or the vicinity thereof can be used as a ground (if so-called body grounding is possible), the extending direction of the antenna element 2 The (second direction) is preferably a direction along the edge 15 of the vehicle body opening in terms of improving the antenna gain as compared with the case where the second direction is not. The second direction is, for example, a direction parallel to or substantially parallel to the edge 15.

  The power supply unit 8 is a power supply point to which a power supply line connected to the receiver is electrically connected. When a coaxial cable is used as the feeder line, the inner conductor of the coaxial cable is electrically connected to the feeder 8 and the outer conductor of the coaxial cable is grounded to a ground portion such as a vehicle body.

  By configuring the connector for electrically connecting the coaxial cable and the power supply unit 8 to the power supply unit 8, the coaxial cable can be easily attached to the power supply unit 8. When an amplifier circuit for amplifying a received signal at the power supply unit 8 is built in the connector mounted on the power supply unit 8, the ground of the amplifier circuit is electrically connected to a ground part such as an outer conductor of the coaxial cable. It is preferable that the power supply unit 8 is electrically connected to the input side of the amplifier circuit, and the inner conductor of the coaxial cable is electrically connected to the output side of the amplifier circuit.

  The shape of the power supply unit 8 may be determined according to the shape of the mounting surface of the attached connector. For example, a square shape such as a square, a substantially square, a rectangle, or a substantially rectangular shape is preferable for mounting. It may be a circle such as a circle, a substantially circle, an ellipse, or a substantially ellipse.

  FIG. 1 shows a rectangular power supply unit 8. The antenna element 1 may be extended downward from a point on the lower side of the power feeding unit 8 as a starting point. The starting point of the antenna element 1 in FIG. 1 is a point on the lower side on the left side of the center point of the lower side of the power feeding unit 8. The intersection of the left side and the lower side of the power supply unit 8 may be used.

  When the antenna element 2 is provided with a point on the right side of the power supply unit 8 or a first connection conductor (not shown) extending from the power supply unit 8, the antenna element 2 extends rightward from the point on the first connection conductor. It only has to be done. The starting point of the antenna element 2 in FIG. 1 is a point on the right side above the center point of the right side of the power feeding unit 8. The intersection between the upper side and the right side of the power supply unit 8 may be used.

  The antenna element 3 may be extended leftward from the end point 1g of the antenna element 1 or a point on the antenna element 1 near the end point 1g. The starting point of the antenna element 3 in FIG. 1 is the end point 1 g of the antenna element 1. It may be another point on the straight line portion of the antenna element 1 between the start point and the end point 1g of the antenna element 1.

In the present invention, the wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength reduction rate is called k, k = 0.64, and λ _g = λ ₀ · k, The sum x2 of the conductor length of the antenna element 2 and the conductor width x6 in the second direction of the feeder 8 is 0.23 · λ _{g to} 0.55 · λ _g , particularly 0.25 · λ _{g to} 0. it is preferred in terms of improved antenna gain is .50 · λ _g.

Further, the conductor length x3 of the third antenna element, the conductor length of the first antenna element from the connection point with the third antenna element to the feeding point, and the first length of the feeding unit The antenna gain is improved when the sum (x1 + x3) with the conductor width x7 in the direction is 0.19 · λ _{g to} 0.40 · λ _g , particularly 0.21 · λ _{g to} 0.37 · λ _g It is preferable in terms.

For example, the center frequency of the terrestrial digital television broadcast band (470 to 770 MHz) is 620 MHz, and λ _{g at} 620 MHz is 309.7 mm. Of the terrestrial digital television broadcast bands, when 470 to 600 MHz, which is currently being broadcast, is used as the reception frequency band, 535 MHz can be set as the center frequency, and 470 to 710 MHz among the terrestrial digital television broadcast bands. 590 MHz as the reception frequency band, 590 MHz can be set as the center frequency.

  In consideration of these, specifically, in the case of the terrestrial digital television broadcasting band (470 to 770 MHz), x1 is 27 to 60 mm (particularly 30 to 55 mm), and x2 is 71 to 170 mm (particularly 77). It is preferable that x3 is 32 to 64 mm (particularly 35 to 60 mm) from the viewpoint of improvement of the antenna gain.

  FIG. 2 is a plan view of a glass antenna 200 for a vehicle that is an embodiment of the present invention. In addition to the components of the vehicle glass antenna 100, the vehicle glass antenna 200 is provided with a ground conductor and a ground portion. The ground portion 7 is provided in the vicinity of the power feeding portion 8 in the third direction, and extends in the third direction starting from the ground portion 7 or a second connection conductor (not shown) extending from the ground portion 7. The antenna element 4 is an antenna element 4 as a ground conductor. The description of the same configuration as in FIG. 1 is omitted.

  The glass antenna for vehicle 200 is a bipolar antenna, and a reception signal can be taken out from the power supply unit 8 on the positive electrode side (hot side) with the ground portion 7 on the negative electrode side (ground side) as a ground reference. The signal is transmitted to a receiver (not shown). In the case of a bipolar antenna, the extending direction (second direction) of the antenna element 2 may be a direction along the edge 15 of the vehicle body opening, but is electrically connected to the ground-side earthing portion 7. Since the antenna element 4 functions as a ground conductor together with the ground portion 7, it does not have to be along the edge portion 15. Thereby, the freedom degree which arrange | positions a glass antenna in the limited margin area | region of the window glass plate 12 increases. Further, if the vehicle body opening of the vehicle to which the window glass plate 12 is attached or the vicinity thereof is a part that cannot be used as a ground (for example, the part is electrically floating from the body ground, or the body itself Is a non-conductive member such as a resin), the bipolar antenna is a preferred mode not only in the improvement of the reception performance but also in the degree of freedom of arrangement.

  The power supply unit 8 and the ground unit 7 are power supply points to which a power supply line connected to the receiver is electrically connected. When a coaxial cable is used as the feeder line, the inner conductor of the coaxial cable is electrically connected to the feeder portion 8, and the outer conductor of the coaxial cable is electrically connected to the ground portion 7.

  The coaxial cable is attached to the power supply unit 8 and the ground unit 7 by mounting the connector for electrically connecting the coaxial cable to the power supply unit 8 and the ground unit 7 on the power supply unit 8 and the ground unit 7. It becomes easy to do. When an amplifier circuit for amplifying signals received at the power supply unit 8 and the ground unit 7 is built in the connector mounted on the power supply unit 8 and the ground unit 7, the ground of the amplifier circuit is connected to the ground unit 7. It is preferable that the external conductor of the coaxial cable is electrically connected, the power feeding unit 8 is electrically connected to the input side of the amplifier circuit, and the inner conductor of the coaxial cable is connected to the output side of the amplifier circuit.

  The shape of the ground portion 7 and the distance between the ground portion 7 and the power feeding portion 8 may be determined according to the shape of the mounting surface of the connector to be attached and the spacing of the mounting surface of the connector. For example, a square shape such as a square, a substantially square, a rectangle, or a substantially rectangular shape is preferable for mounting. It may be a circle such as a circle, a substantially circle, an ellipse, or a substantially ellipse. Further, the area of the ground part 7 and the area of the power feeding part 8 may be the same or different. Further, the right side edge of the ground part 7 and the left side edge of the power feeding part 8 are opposed to each other. In addition, it is preferable that the virtual straight line connecting the center of gravity of the ground portion 7 and the center of gravity of the power feeding unit 8 is horizontal to the extending direction of the antenna element 2 and is horizontal to the extending direction of the antenna element 4.

  FIG. 2 shows a rectangular grounding portion 7 and a power feeding portion 8. The right side of the ground part 7 and the left side of the power feeding part 8 are parallel or substantially parallel. The antenna element 4 may be extended in the left direction starting from a point on the left side of the ground portion 7. The starting point of the antenna element 4 in FIG. 2 is a point on the left side above the center point of the left side of the ground portion 7. The intersection of the upper side and the left side of the power feeding unit 7 may be used. As shown in FIG. 2, it is preferable that the extending direction of the antenna element 2 and the extending direction of the antenna element 4 are in a straight line.

In the present invention, the wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength reduction rate is called k, k = 0.64, and λ _g = λ ₀ · k, The distance (x2 + x4 + x10) of the shortest path from the tip of the antenna element 2 to the tip of the antenna element 4 in the first direction and the second direction through the gap x10 between the conductor and the feeding portion 8 and the ground portion 7 is 0.57 · λ _{g to} 1.3 · λ _g , particularly 0.63 · λ _{g to} 1.2 · λ _g is preferable in terms of improving the antenna gain.

  For example, in the case of a terrestrial digital television broadcasting band (470 to 770 MHz), x2 may be 71 to 170 mm (especially 77 to 155 mm), and x4 may be 70 to 210 mm (especially 75 to 190 mm). X10 is preferably 5 to 25 mm (especially 5 to 20 mm) from the viewpoint of improving the antenna gain in the low frequency side band in the terrestrial digital television broadcasting band.

In the present invention, the wavelength in the air at the center frequency of the desired broadcast frequency band is referred to as λ ₀ , the glass wavelength shortening rate is referred to as k, k = 0.64, and λ _g = λ ₀ · k. When the distance between the tip of the antenna element 3 and the tip of the antenna element 4 through the conductor and the gap between the feeding portion 8 and the ground portion 7 is the distance of the shortest path in the first direction and the third direction (x1 + x3 + x4 + x10) ) Is preferably 0.48 · λ _{g to} 1.0 · λ _g , particularly 0.52 · λ _{g to} 0.95 · λ _g in terms of improving the antenna gain.

  For example, in the case of a terrestrial digital television broadcast band (470 to 770 MHz), x1 may be 27 to 60 mm (particularly 30 to 55 mm), and x3 may be 32 to 64 mm (particularly 35 to 60 mm). , X4 is 70 to 210 mm (especially 75 to 190 mm) and x10 is 5 to 25 mm (especially 5 to 20 mm), so that the antenna gain in the high frequency side band in the terrestrial digital television broadcasting band It is preferable in terms of improvement.

  Although not shown in FIG. 2, a first antenna element that is constituted by a plurality of antenna elements extending in the third direction as an antenna conductor starting from at least one of the antenna element 1 and the power feeding unit 8. The antenna element 3 may be included in the first antenna element group.

  In addition, the antenna conductor includes a second antenna element group including a plurality of antenna elements extending in the second direction starting from at least one of the power feeding unit 8 and the first connection conductor (not shown). The antenna element 2 may be included in the second antenna element group.

  In addition, as a ground conductor, a third antenna element group including a plurality of antenna elements extending in the third direction starting from at least one of the ground portion 7 and the second connection conductor (not shown) is provided. Alternatively, the antenna element 4 may be included in the third antenna element group.

  In this way, by forming an element group composed of a plurality of antenna elements that are parallel or substantially parallel to each other at capacitive coupling intervals, the antennas can be easily tuned by changing their lengths and intervals.

  FIG. 3 is a plan view of a glass antenna 300 for a vehicle that is an embodiment of the present invention. In addition to the constituent elements of the glass antenna 200 for a vehicle, the glass antenna 300 for a vehicle includes an antenna element 5 that is a fifth antenna element that extends in the second direction starting from the end point 1g extended by the antenna element 1 or the vicinity of the end point. It is a structure provided as an antenna conductor. The description of the same configuration as in FIGS. The glass antenna 300 for a vehicle is a bipolar antenna, and a reception signal can be taken out from the power supply unit 8 on the positive electrode side (hot side) with the ground portion 7 on the negative electrode side (ground side) as a ground reference. It is transmitted to a receiver (not shown).

  The antenna element 5 extends in the right direction starting from an end point 1g of the antenna element 1 or a point on the antenna element 1 near the end point 1g. The starting point of the antenna element 5 in FIG. 3 is the end point 1 g of the antenna element 1. As shown in FIG. 3, it is preferable that the extending direction of the antenna element 5 and the extending direction of the antenna element 3 are in a straight line.

In the present invention, the wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength reduction rate is called k, k = 0.64, and λ _g = λ ₀ · k, The sum (x3 + x5) of the conductor length x3 in the extending direction of the antenna element 3 and the conductor length x5 in the extending direction of the antenna element 5 is 0.38 · λ _{g to} 0.65 · λ _g , particularly 0.42 · λ. it is preferred in terms of improved antenna gain is _{g ~0.6} · _{λ g.}

  For example, in the case of a terrestrial digital television broadcasting band (470 to 770 MHz), x3 may be 32 to 64 mm (particularly 35 to 60 mm), and x5 may be 65 to 150 mm (particularly 80 to 130 mm). It is preferable in terms of improving the antenna gain in the high frequency side band in the terrestrial digital television broadcasting band.

  Although not shown in FIG. 3, the antenna conductor may include a fourth antenna element group including a plurality of antenna elements extending in the second direction from the antenna element 1 as a starting point. The antenna element 5 may be included in the fourth antenna element group. As with the antenna element group described above, the antenna can be easily tuned.

  FIG. 7 shows an example in which the glass antenna according to the present invention is arranged on the window glass plate 12. Four glass antennas are disposed in the upper left region, upper right region, lower left region, and lower right region of the window glass 12, respectively. In FIG. 7, when the window glass plate 12 is a rear window glass plate, a defogger (not shown) is formed in the central region. However, the present invention is not limited to this, and may be provided in at least one of the four regions. Moreover, you may provide in the center upper area | region, the center lower area | region, the center left area | region, and the center right area | region instead of the left side and the right side.

  In the present invention, when the glass antenna of the window glass plate 12 and the glass antenna in the upper left region are arranged as shown in FIG. 7, the shape of the glass antenna in the upper left region is symmetrical. You may arrange | position in the state illustrated by the shape at the upper right side area | region of FIG. The same applies to the lower region.

  When a plurality of glass antennas are installed as described above, diversity reception is achieved and reception characteristics are improved, which is preferable.

  The glass antenna described above is not provided with an auxiliary antenna conductor. However, the present invention is not limited to this, and for impedance matching, phase adjustment, directivity adjustment, etc., an auxiliary element such as a substantially T-shape, a substantially L-shape, a loop shape, etc. with or without a connecting conductor on the antenna element An antenna element may be attached.

  Further, a conductor layer made of an antenna conductor may be provided inside or on the surface of the synthetic resin film, and the synthetic resin film with a conductor layer may be formed on the vehicle inner surface or vehicle outer surface of the window glass plate to form a glass antenna. Furthermore, it is good also as a glass antenna by forming the flexible circuit board in which the antenna conductor was formed in the vehicle inner surface or vehicle outer surface of a window glass board.

  The window glass plate on which the vehicle high-frequency glass antenna according to the present invention is provided may be any glass such as a windshield, a door glass, a side window glass, and a rear window glass, and is not particularly limited.

  The attachment angle of the window glass plate to the vehicle is preferably 15 to 90 °, particularly 30 to 90 ° with respect to the horizontal direction.

  The antenna conductor is formed by printing and baking a paste containing a conductive metal such as a silver paste on the inner surface of the window glass plate. However, the present invention is not limited to this method, and a linear or foil-like body made of a conductive material such as copper may be formed on the vehicle side surface or the vehicle outer surface of the window glass plate and adhered to the window glass. You may form with an agent etc. and may provide in the inside of window glass itself.

  Further, a concealing film may be formed on the surface of the window glass, and a part or the whole of the antenna conductor may be provided on the concealing film. The concealing film may be a ceramic such as a black ceramic film. In this case, when viewed from the outside of the window glass, the portion of the antenna conductor provided on the masking film by the masking film becomes invisible from the outside of the vehicle, and the window glass has an excellent design. In the configuration shown in the drawing, at least a part of the feeding portion and the antenna conductor is formed on the concealing film, so that only a thin straight portion of the conductor is seen in the vehicle exterior view, which is preferable in terms of design.

  The present invention will be described below with reference to examples, but the present invention is not limited to these examples, and various modifications and substitutions are made to these examples without departing from the scope of the present invention. be able to.

  A square glass substrate is assumed to be a window glass, and the glass antenna shown in FIGS. 4, 5 and 6 is provided on one side assumed to be the center of the glass substrate and the inner surface of the vehicle to constitute a high-frequency glass antenna for automobiles. . Assume that there is no car body or defogger. The glass antenna shown in FIGS. 4, 5 and 6 has an antenna configuration suitable for reception in the terrestrial digital television broadcasting band (470 to 770 MHz). In particular, FIGS. 5 and 6 correspond to glass antennas according to the present invention. FIG. 5 includes first antenna element groups 3a and 3b and second antenna element groups 2a, 2b and 2c. Further, fourth antenna element groups 5a and 5b are provided.

FIG. 4 is a plan view of the vehicle glass antenna 400. Constants such as the thickness of the glass substrate and dimensions of each part of the vehicle glass antenna 400 are as follows:
Glass substrate thickness: 3.5 mm
Dielectric constant of glass substrate: 6.5
Conductor width of each antenna element: 0.8mm
x30: 10 mm
x28: 43 mm
x26: 25mm
x27: 20 mm
x24: 108mm
x31: 50 mm
x21: 90 mm
x22: 120 mm
x32: 20 mm
x33: 15 mm
x29: 20 mm
Antenna height x23: 75mm
And

FIG. 5 is a plan view of the glass antenna 500 for a vehicle. The constants such as the thickness of the glass substrate and the dimensions of each part of the vehicle glass antenna 500 are as follows:
Glass substrate thickness: 3.5 mm
Specific permittivity of glass: 6.5
Conductor width of each antenna element: 0.8mm
x10: 10 mm
x6, x7: 20 mm
x8, x9: 20 mm
x12: 10 mm
x4: 100 mm
x3: 33 mm
x2: 107 mm
x11: 10 mm
Antenna height x1: 40mm
And

FIG. 6 is a plan view of the glass antenna 600 for a vehicle. The constants such as the thickness of the glass substrate and the dimensions of each part of the vehicle glass antenna 600 are as follows:
Glass substrate thickness: 3.5 mm
Specific permittivity of glass: 6.5
Conductor width of each antenna element: 0.8mm
x10: 10 mm
x8, x9: 20 mm
x6, x7: 20 mm
x12: 10 mm
x4: 90 mm
x3: 38 mm
x2: 130 mm
x5: 120 mm
x11: 10 mm
Antenna height x1: 40mm
And

  With respect to the glass antennas for vehicles 400, 500, and 600, numerical calculation is performed by an electromagnetic field simulation based on the FDTD method (Finite-Difference Time-Domain method) every 15 Hz at a frequency of 380 to 860 MHz, and a return loss characteristic (reflection coefficient) s11 Was calculated.

  FIG. 8 shows a simulation result of s11 of the antennas 400, 500, and 600. □ indicates the calculated value of the antenna model 400, ▲ indicates the calculated value of the antenna model 500, and ● indicates the calculated value of the antenna model 600.

  As shown in FIG. 8, it can be seen that the antennas 400, 500, and 600 have antenna characteristics having two resonance frequencies while ensuring a wide band. In particular, although the heights of the antennas 500 and 600 are lower than the height of the antenna 400, it can be seen that the antennas 500 and 600 have a low reflection coefficient as the antenna characteristic compared to the antenna 400.

  That is, even if the height of the antenna itself is lowered, two resonances can be realized by applying the present invention. The resonance position and bandwidth can be tuned by adjusting the length of the antenna element in the left-right direction (that is, the second direction or the third direction).

  Subsequently, the glass antenna shown in FIGS. 4 and 6 was attached to the windshield of an actual vehicle to constitute a high frequency glass antenna for a vehicle, and the average gain for a half circumference in the vehicle front direction was measured by measuring the received power. .

  The antenna gain was measured by radiating radio waves to the automobile and rotating the automobile by 180 ° at every angle of 1 °. The radio wave was horizontally polarized, and the frequency was changed every 3 MHz in the range of 470 to 770 MHz. The elevation angle between the radio wave transmission position and the antenna conductor was measured in the horizontal direction (when the plane parallel to the ground is elevation angle = 0 ° and the zenith direction is elevation angle = 90 °, the elevation angle = 0 °).

Each dimension of the antenna manufactured to have the form of the glass antenna 400 shown in FIG.
Conductor width of each antenna element: 0.4 mm
x30: 10 mm
x28, x29: 20 mm
x26, x27: 20mm
x24: 100 mm
x31: 56mm
x21: 90 mm
x22: 130 mm
x32: 15 mm
x33: 10 mm
Antenna height x23: 55mm
It is.

For comparison with the glass antenna 400, each dimension of the antenna manufactured to have the form of the glass antenna 600 shown in FIG.
x10: 10 mm
x8, x9: 20 mm
x6, x7: 20 mm
x12: 10 mm
x4: 90 mm
x3: 43 mm
x2: 125 mm
x5: 120 mm
x11: 10 mm
Antenna height x1: 40mm
It is.

  FIG. 9 shows measured data of antenna gain measured under the above conditions. The antenna gain on the vertical axis represents the average value of the antenna gain measured every 1 ° by rotating the vehicle by 180 ° (the average value of the antenna gain every 3 MHz at all frequencies of 470 to 770 MHz). The broken line on FIG. 9 is the measurement result for the glass antenna 400. The solid line on FIG. 9 is the measurement result of the glass antenna 600. As shown in FIG. 9, it can be seen that, even on an actual vehicle, by using the antenna configuration according to the present invention described above, excellent antenna characteristics covering a wide band can be obtained even if the height is reduced.

  INDUSTRIAL APPLICABILITY The present invention is used for an automotive glass antenna that receives terrestrial digital TV broadcasts, UHF band analog TV broadcasts, US digital TV broadcasts, digital television broadcasts in the European Union region, or digital TV broadcasts in the People's Republic of China. In addition, Japanese FM broadcast band (76-90 MHz), US FM broadcast band (88-108 MHz), TV VHF band (90-108 MHz, 170-222 MHz), 800 MHz band (810-960 MHz) for automobile telephones, automobiles 1.5 GHz band (1.429 to 1.501 GHz) for telephone, UHF band (300 MHz to 3 GHz), GPS (Global Positioning System), GPS signal of artificial satellite 1575.42 MHz), VICS (registered trademark) (Vehicle Information) and Communication System, Vehicle Information and Communication System: 2.5 GHz).

  Furthermore, ETC communication (Electronic Toll Collection System: non-stop automatic toll collection system, roadside wireless device transmission frequency: 5.795 GHz or 5.805 GHz, roadside wireless device reception frequency 5.835 GHz or 5.845 GHz), dedicated narrow Regional communication (DSRC: Dedicated Short Range Communication, 915 MHz band, 5.8 GHz band, 60 GHz band), microwave (1 GHz to 3 THz), millimeter wave (30 to 300 GHz), keyless entry system for automobile (300 to 450 MHz), and And SDARS (Satellite Digital Audio Radio Service (2.34 GHz, 2.6 GHz)) communication.

It is a top view of the glass antenna 100 for vehicles which is one Embodiment of this invention. It is a top view of the glass antenna 200 for vehicles which is one Embodiment of this invention. It is a top view of the glass antenna 300 for vehicles which is one Embodiment of this invention. It is a top view of the glass antenna 400 for vehicles. It is a top view of the glass antenna 500 for vehicles which is one Embodiment of this invention. It is a top view of the glass antenna 600 for vehicles which is one Embodiment of this invention. It is the arrangement | positioning figure to the window glass plate of the glass antenna for vehicles. It is a measurement result of a return loss characteristic. It is a measurement result of a gain characteristic.

Explanation of symbols

1-5 Antenna element 7 Feeding part (positive side)
8 Grounding part (negative electrode side)
DESCRIPTION OF SYMBOLS 12 Window glass board 13 Peripheral part of window glass board 12 Car body opening edge of window 100,200, ..., 600 Glass antenna

Claims (16)

A vehicle glass antenna having a vehicle window glass plate provided with an antenna conductor and a feeding portion,
The antenna conductor is
A first antenna element extending in a first direction that is a direction perpendicular to or substantially perpendicular to a horizontal direction, starting from the feeding portion;
A second antenna element extending in a second direction, which is a horizontal or substantially horizontal direction, starting from the power supply unit or via a first connection conductor extending from the power supply unit;
And a third antenna element extending in a third direction that is opposite to the second direction, starting from an end point near the end point of the first antenna element or in the vicinity of the end point. Glass antenna.   The antenna conductor includes a first antenna element group including a plurality of antenna elements extending in the third direction, starting from at least one of the first antenna element and the power feeding unit, and The glass antenna for a vehicle according to claim 1, wherein the antenna element is included in the first antenna element group.   The antenna conductor includes a second antenna element group including a plurality of antenna elements extending in the second direction starting from at least one of the power feeding unit and the first connection conductor, The antenna element according to claim 1, wherein the antenna element is included in the second antenna element group. The vehicle glass antenna is provided with a ground conductor and a ground portion,
The ground part is provided in the vicinity of the power feeding part,
The grounding conductor includes a fourth antenna element extending in the third direction from the grounding part as a starting point or via a second connecting conductor extending from the grounding part. The glass antenna for vehicles as described in any one.   The ground conductor includes a third antenna element group including a plurality of antenna elements extending in the third direction starting from at least one of the ground portion and the second connection conductor, The antenna element according to claim 4, wherein the antenna element is included in the third antenna element group. The wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength shortening rate is called k, k = 0.64, and λ _g = λ ₀ · k,
Shortest in the first direction and the second direction through the gap between the conductor and the feeding portion and the ground portion from the tip of the second antenna element to the tip of the fourth antenna element The glass antenna for vehicles according to claim 4 or 5 whose distance of a path is 0.57 * lambda _g- 1.3 * lambda _g .   Shortest in the first direction and the second direction through the gap between the conductor and the feeding portion and the ground portion from the tip of the second antenna element to the tip of the fourth antenna element In the path, the conductor length from the tip of the second antenna element to the gap of the power feeding unit is 71 to 170 mm, the gap is 5 to 40 mm, and from the tip of the fourth antenna element The glass antenna for vehicles according to any one of claims 4 to 6 whose conductor length to said gap of said ground part is 70-210 mm. The wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength shortening rate is called k, k = 0.64, and λ _g = λ ₀ · k,
The shortest in the first direction and the third direction through the gap between the conductor and the feeding portion and the ground portion from the tip of the third antenna element to the tip of the fourth antenna element distance of the path is a _{0.48 · λ g ~1.0 · λ g} , the vehicular glass antenna according to any one of claims 4 7. The shortest in the first direction and the third direction through the gap between the conductor and the feeding portion and the ground portion from the tip of the third antenna element to the tip of the fourth antenna element The conductor length of the third antenna element in the path is 32 to 64 mm;
The conductor length from the connection point of the first antenna element with the third antenna element to the gap of the feeding portion is 5 to 60 mm,
The gap distance is 5 to 40 mm,
The glass antenna for vehicles according to any one of claims 4 to 8 whose conductor length from the tip of said 4th antenna element to said gap of said earth part is 70-210 mm.   10. The antenna antenna according to claim 1, wherein the antenna conductor includes a fifth antenna element extending in the second direction starting from an end point near the end point of the first antenna element or in the vicinity of the end point. Vehicle glass antenna.   The antenna conductor includes a fourth antenna element group including a plurality of antenna elements extending in the second direction starting from the first antenna element, and the fifth antenna element includes a fourth antenna element. The glass antenna for vehicles according to claim 10 included in a group of antenna elements. The wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength shortening rate is called k, k = 0.64, and λ _g = λ ₀ · k,
The vehicle according to claim 10 or 11, wherein a sum of a conductor length of the third antenna element and a conductor length of the fifth antenna element is 0.38 · λ _{g to} 0.65 · λ _g. Glass antenna. The conductor length of the third antenna element is 32 to 64 mm,
The glass antenna for vehicles according to any one of claims 10 to 12 whose conductor length of said 5th antenna element is 65-150 mm. The wavelength in the air at the center frequency of the desired broadcast frequency band is called λ ₀ , the glass wavelength shortening rate is called k, k = 0.64, and λ _g = λ ₀ · k,
The sum of the conductor length of the second antenna element and the conductor width in the second direction of the feeding portion is 0.23 · λ _{g to} 0.55 · λ _g ,
The conductor length of the third antenna element, the conductor length of the first antenna element from the connection point with the third antenna element to the feeding point, and the conductor in the first direction of the feeding unit The glass antenna for vehicles according to any one of claims 1 to 13 whose sum with a width is 0.19 * lambda _g -0.40 * lambda _g . The sum of the conductor length of the second antenna element and the conductor width in the second direction of the feeding portion is 71 to 170 mm,
The conductor length of the third antenna element is 32 to 64 mm,
The sum of the conductor length of the first antenna element from the connection point with the third antenna element to the power feeding unit and the conductor width in the first direction of the power feeding unit is 27 to 60 mm. The glass antenna for vehicles as described in any one of Claim 1 to 14.   The vehicle window glass board provided with the glass antenna for vehicles as described in any one of Claim 1 to 15.

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