JP7411487B2 - antenna device - Google Patents

Description

The present disclosure relates to an antenna device.

In recent years, composite antennas that can receive signals in multiple frequency bands such as AM broadcast waves, FM broadcast waves, digital terrestrial television broadcast waves, and DAB (Digital Audio Broadcasting) have become popular as antenna devices installed in vehicles such as automobiles. Antenna devices with integrated elements have been put into practical use. For example, an antenna device is known that includes a plurality of antenna elements inside an air spoiler whose outer panel is made of synthetic resin and receives a plurality of radio waves of different frequency bands (FM broadcast waves, AM broadcast waves, TV broadcast waves, etc.). (For example, see Patent Document 1).

Japanese Patent Application Publication No. 2004-128696

However, conventional antenna devices cannot necessarily be said to have sufficient reception performance for radio waves in these multiple frequency bands.

The present disclosure provides an antenna device that can receive radio waves in at least three different frequency bands with a simple configuration and with high sensitivity.

This disclosure:
An antenna device that is provided on a vehicle member attached to a vehicle body and receives radio waves in a first frequency band, radio waves in a second frequency band, and radio waves in a third frequency band,
A power supply unit,
an antenna having a first antenna section electrically connected to the power feeding section; and a second antenna section electrically connected to the power feeding section;
an amplifier electrically connected to the power feeding section,
The first antenna section includes a first element including a portion extending in a first direction, and a first loop element having a loop-shaped outer edge and connected to an end of the first element opposite to the power feeding section. and has
The second antenna section includes a second element including a portion extending in the first direction, and a second loop having a loop-shaped outer edge connected to an end of the second element opposite to the power feeding section. It has an element,
The first loop element includes a portion extending in the first direction and a portion extending in a second direction different from the first direction,
The second loop element includes a portion extending in the first direction and a portion extending in a third direction opposite to the second direction,
The first loop element and the second loop element are located apart from each other to provide an antenna device.

According to the present disclosure, radio waves in at least three different frequency bands can be received with high sensitivity with a simple configuration.

1 is an exploded perspective view illustrating a vehicle member in which an antenna device is installed and a vehicle body to which the vehicle member is attached, according to an embodiment; FIG. FIG. 1 is a cross-sectional view illustrating a vehicle member on which an antenna device is installed and a vehicle body to which the vehicle member is attached, according to an embodiment. FIG. 2 is a plan view illustrating a vehicle member in which an antenna device is installed and a vehicle body to which the vehicle member is attached, according to an embodiment. FIG. 2 is a plan view showing a first configuration example of an antenna in one embodiment. It is a top view which shows the 2nd structural example of the antenna in one embodiment. FIG. 7 is a plan view showing third to seventh configuration examples of the antenna in one embodiment. Relationship between the antenna capacity C _a of the antenna and the antenna widths W ₁ and W ₂ when the distances D ₁ and D ₂ are fixed at 135 mm when the maximum widths H ₁ and H ₂ are both 10 mm and 110 mm. This is a graph illustrating. Relationship between the antenna capacity C _a of the antenna and the antenna widths W 1 and W ₂ when the maximum widths H ₁ and H ₂ are fixed to 10 mm when the _distances D ₁ and D ₂ are both 35 mm and 135 mm This is a graph illustrating. It is a graph illustrating the relationship between the antenna capacitance C _a and the maximum widths H ₁ and H ₂ of the antenna when the distances D ₁ and D ₂ are fixed at 135 mm. The relationship between the received voltage V _a of the antenna 30 and the antenna widths W ₁ and W ₂ when the distances D ₁ and D ₂ are fixed at 135 mm when the maximum widths H ₁ and H ₂ are both 10 mm and 110 mm. It is a graph illustrating a relationship. The relationship between the received voltage V _a of the antenna ₃₀ and the antenna widths W 1 and W ₂ when the maximum widths H ₁ and H ₂ are fixed at 10 mm, when the distances D ₁ and D ₂ are both 35 mm and 135 mm. It is a graph illustrating a relationship. It is a graph illustrating the relationship between the received voltage V _a of the antenna 30 and the maximum widths H ₁ and H ₂ when the distances D ₁ and D ₂ are fixed at 135 mm. FIG. 2 is a plan view showing a portion of the antenna that contributes to reception of VHF band radio waves in an embodiment. An example of the measurement results of the average antenna gain in the FM broadcast wave band is shown when the vertical width H _FM and the horizontal width W _FM of the antenna including the antenna portion shown in FIG. 13 are changed. An example of the measurement results of the average antenna gain in the DAB band III band is shown when the vertical width H _FM and the horizontal width W _FM of the antenna including the antenna portion shown in FIG. 13 are changed. 15 is a graph showing the measurement results of FIG. 14. 16 is a graph showing the measurement results of FIG. 15. An example of the measurement results of the average antenna gain in the FM broadcast wave band is shown when the aspect ratio of the antenna including the antenna portion of FIG. 13 is changed. FIG. 2 is a plan view showing a portion of the antenna that contributes to reception of radio waves in band III of DAB, among the antennas in one embodiment. An example of the measurement results of the average antenna gain in the FM broadcast wave band is shown when the vertical width H _DAB and the horizontal width W _DAB of the antenna including the antenna portion shown in FIG. 19 are changed. An example of the measurement results of the average antenna gain in the DAB band III band is shown when the vertical width H _DAB and the horizontal width W _DAB of the antenna including the antenna portion shown in FIG. 19 are changed. 21 is a graph showing the measurement results of FIG. 20. 22 is a graph showing the measurement results of FIG. 21. An example of the measurement result of the average antenna gain in the DAB band III band is shown when the aspect ratio of the antenna including the antenna portion of FIG. 19 is changed. An example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the loop vertical width of the antenna shown in FIG. 4 is changed is shown. An example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the distance between the loop elements of the antenna in FIG. 4 is changed is shown. An example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the distances D ₁ and D ₂ from the virtual plane 12c are changed is shown. An example of the measurement result of the average antenna gain in the UHF band of the antenna of FIG. 4 is shown.

Embodiments according to the present disclosure will be described below with reference to the drawings. Note that for ease of understanding, the scale of each part in the drawings may differ from the actual scale. In parallel, perpendicular, perpendicular, horizontal, perpendicular, up and down, left and right directions, deviations are allowed to an extent that does not impair the effects of the embodiment. The shape of the corner portion is not limited to a right angle, but may be rounded in an arcuate manner. The X-axis direction, Y-axis direction, and Z-axis direction represent a direction parallel to the X-axis, a direction parallel to the Y-axis, and a direction parallel to the Z-axis, respectively. The X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. The XY plane, YZ plane, and ZX plane are, respectively, a virtual plane parallel to the X-axis direction and the Y-axis direction, a virtual plane parallel to the Y-axis direction and the Z-axis direction, and a virtual plane parallel to the Z-axis direction and the X-axis direction. represents.

FIG. 1 is an exploded perspective view illustrating a vehicle member on which an antenna device according to an embodiment is installed and a vehicle body to which the vehicle member is attached. An antenna device 101 shown in FIG. 1 is an example of an antenna device provided in a vehicle member attached to a vehicle body. FIG. 1 shows an example in which an antenna device 101 is mounted on a spoiler 18 attached to a lift gate 10 that is a part of a vehicle body. The lift gate 10 is a door attached to the rear of the vehicle body so as to be openable and closable, and a window glass 11 is attached thereto. The spoiler 18 is an example of a vehicle member, and is a resin component fixed to the top of the lift gate 10. The spoiler 18 has an inner cover 14 and an outer cover 13. The antenna device 101 includes a waterproof connector 16, an antenna 30, and an amplifier 60.

The waterproof connector 16 is an example of a power feeding section for feeding power to the antenna 30, and is electrically connected to the antenna 30. The waterproof connector 16 is connected to the input terminal of the amplifier 60 via a cable 61 (wiring). The waterproof connector 16 is attached to, for example, an antenna outlet 12b formed in the metal portion 12 of the vehicle body. The antenna extraction port 12b is an opening formed on the surface of the metal portion 12 on the outside of the vehicle.

The antenna 30 is a conductor that receives radio waves in at least three different frequency bands, and in this example, a portion of the antenna 30 is placed inside the spoiler 18 while being sandwiched between the inner cover 14 and the outer cover 13. be done. The antenna 30 may be built into the spoiler 18 or may be provided on the outer surface of the spoiler 18. The antenna 30 is a linear conductive member, and may be formed of, for example, a conductive wire, conductive paint, a metal rod, a metal plate, or the like.

Amplifier 60 has an input terminal electrically connected to waterproof connector 16 and amplifies the signal received by antenna 30. The signal amplified by the amplifier 60 is supplied to a receiving device (not shown) mounted on the vehicle body. In this example, amplifier 60 is attached to the top of liftgate 10.

FIG. 2 is a cross-sectional view illustrating a vehicle member on which an antenna device according to an embodiment is installed and a vehicle body to which the vehicle member is attached. A high mount stop lamp 17 may be mounted on the spoiler 18. When the high mount stop lamp 17 is mounted on the spoiler 18, by arranging the antenna 30 above the high mount stop lamp 17, it is possible to suppress a decrease in the radio wave reception sensitivity of the antenna 30. Furthermore, in order to suppress a decrease in the radio wave receiving sensitivity of the antenna 30, it is preferable that the antenna 30 be arranged so as not to straddle the wiring connected to the high mount stop lamp 17. In FIG. 2, illustration of the outer cover 13 is omitted.

The portion where the antenna 30 is formed or attached may be the inner cover 14 or outer cover 13 (not shown) which is a dielectric, or may be a dielectric substrate (not shown) fixed to the inner cover 14 or the outer cover 13. good. Since the antenna 30 is formed on the dielectric substrate, attachment of the antenna 30 to the spoiler 18 is facilitated. Dielectric substrates include printed circuit boards, flexible circuit boards, and the like.

The element of the antenna 30 passes through the hole 20 formed in the inner cover 14 and is connected to the waterproof connector 16 attached to the antenna outlet 12b of the metal part 12 of the vehicle body. Further, a ZX plane passing through the antenna outlet 12b and perpendicular to the Y-axis direction is defined as a virtual plane 12c. The virtual plane 12c will be explained in detail in connection with the antenna 30 shown in FIG.

FIG. 3 is a plan view illustrating a vehicle member in which an antenna device according to an embodiment is installed and a vehicle body to which the vehicle member is attached, and specifically, a diagram shown from a viewpoint from above the vehicle. In this example, when viewed from the normal direction (in this example, the Z-axis direction) of a horizontal plane (in this example, the It intersects with the end side 12a. The metal portion 12 is, for example, the upper part of the lift gate 10. In the example shown in FIGS. 2 and 3, the metal portion 12 is a flange to which the window glass 11 is attached, and the edge 12a is the edge of the flange.

Since the antenna 30 and the end side 12a intersect in this way when viewed from the Z-axis direction, a part of the antenna 30 does not overlap the metal portion 12 in the Z-axis direction when viewed from the Z-axis direction. Thereby, a part of the antenna 30 can form a part (a part with a width S ₂ ) that does not overlap with the metal part 12 in the Z-axis direction, and a reduction in reception sensitivity of the antenna 30 can be suppressed. The width _S2 is the distance from the end side 12a to the end of the spoiler 18 in the Y-axis direction. The width _S1 is the width of the spoiler 18 in the vehicle width direction. Note that the antenna 30 does not need to intersect the end side 12a when viewed from the Z-axis direction. As forms in which the antenna 30 does not intersect with the end side 12a, there are a form in which the entire antenna 30 overlaps with the metal portion 12 in the Z-axis direction, and a form in which the entire antenna 30 does not overlap with the metal portion 12 in the Z-axis direction.

FIG. 4 is a plan view showing a first configuration example of an antenna in one embodiment. The antenna 30 shown in FIG. 4 is configured to be able to receive radio waves in a first frequency band, radio waves in a second frequency band, and radio waves in a third frequency band, and resonates at frequencies in each frequency band at least equal to or higher than the VHF band. .

For example, the first frequency band is a MF (Medium Frequency) band with a frequency of 300 kHz to 3 MHz, and the second frequency band and the third frequency band are VHF (Very High Frequency) bands with a frequency of 30 MHz to 300 MHz. In this case, the first frequency band is set to the AM broadcast wave band included in the MF band, the second frequency band is set to the FM broadcast wave band included in the VHF band, and the third frequency band is set to the band of FM broadcast waves included in the VHF band. It may be set to the DAB band III included in the band.

The antenna 30 may further be formed to be able to receive radio waves in the fourth frequency band, and in this case, resonates at a frequency in the fourth frequency band. For example, the fourth frequency band is a UHF (Ultra High Frequency) band of 300 MHz to 3 GHz. In this case, the frequency band may be set to the terrestrial digital television broadcast wave band of 470 MHz to 720 MHz included in the UHF band.

The antenna 30 has a first antenna section 40 and a second antenna section 50. The first antenna section 40 is an antenna element electrically connected to the waterproof connector 16, and the second antenna section 50 is an antenna element electrically connected to the waterproof connector 16. The first antenna section 40 has a first element 41 and a first loop element 42, and the second antenna section 50 has a second element 51 and a second loop element 52. Note that "to be electrically connected" is not limited to a configuration in which the first antenna part 40 and the second antenna part 50 are directly connected to the waterproof connector 16 as shown in FIG. Contains configuration.

The first element 41 is a conductor portion including a portion extending in the first direction. In this example, the first element 41 has an end 41a connected to the waterproof connector 16 and an end 41b opposite to the waterproof connector 16, and at least It has one (in the case of FIG. 4, two) bends.

The first loop element 42 is a conductor portion having a loop-shaped outer edge and connected to the end portion 41b of the first element 41 on the opposite side from the waterproof connector 16. The first loop element 42 includes portions 43 and 45 extending in a first direction, and portions 44 and 46 extending in a second direction different from the first direction. In this example, portions 43 and 45 are opposed in the X-axis direction, and portions 44 and 46 are opposed in the Y-axis direction.

The second element 51 is a conductor portion including a portion extending in the first direction. In this example, the second element 51 has an end 51a connected to the waterproof connector 16 and an end 51b opposite to the waterproof connector 16, and at least It has one (in the case of FIG. 4, two) bends. Note that the "bent part" is not limited to a part where the first element 41 and the second element 51 are bent at right angles as shown in FIG. 4, but any part where the stretching direction changes, for example, a curved part. It may also be a portion where the included radius of curvature is minimal.

The second loop element 52 is a conductor portion having a loop-shaped outer edge and connected to the end portion 51b of the second element 51 on the opposite side from the waterproof connector 16. The second loop element 52 includes portions 53, 55 extending in a first direction and portions 54, 56 extending in a third direction opposite to the second direction. In this example, portions 53 and 55 are opposed in the X-axis direction, and portions 54 and 56 are opposed in the Y-axis direction.

The first loop element 42 and the second loop element 52 are located apart from each other, and in this example, they are arranged apart in the X-axis direction so that there is a gap between the portions 43 and 53. By arranging the first loop element 42 and the second loop element 52 apart from each other, the antenna 30 can receive radio waves in at least three different frequency bands with high sensitivity with a simple configuration.

In the example shown in FIG. 4, the first direction is a direction away from the metal portion 12 of the vehicle body when viewed from the Z-axis direction. The first element 41 and the second element 51 intersect with the end side 12 a of the metal portion 12 when the vehicle member on which the antenna device 101 is installed is seen from the normal direction of the horizontal plane with the vehicle member attached to the vehicle body. By intersecting in this way, a portion of the antenna 30 does not overlap the metal portion 12 in the Z-axis direction, so that reduction in reception sensitivity of the antenna 30 can be suppressed.

The first element 41 and the second element 51 are connected to different connection points (specifically, terminals) in the waterproof connector 16. The first element 41 is connected to the waterproof connector 16 at the end 41a, and the second element 51 is connected to the waterproof connector 16 at the end 51a. Since the first element 41 and the second element 51 are connected to the common waterproof connector 16 at mutually different connection points, the first element 41 and the second element 51 can be independently connected to the common waterproof connector 16. In particular, when the first element 41 and the second element 51 are made of wires such as AV wires, the work of connecting the first element 41 and the second element 51 to the waterproof connector 16 becomes easy.

In this example, the first direction is substantially perpendicular to the second and third directions, so the receiving sensitivity of the antenna 30 is likely to improve. "Substantially orthogonal" may include orthogonal. In this example, the first direction is parallel to the positive Y-axis direction, the second direction is parallel to the negative X-axis direction, and the third direction is parallel to the positive X-axis direction.

In this example, the first loop element 42 has a substantially rectangular outer edge, so that the reception sensitivity of the antenna 30 is likely to be improved. The substantially rectangular shape includes, for example, a rectangular shape having a curved portion on at least one of its four sides and four corners. Note that even if the first loop element 42 has a loop shape whose outer edge is different from a substantially rectangular shape, it is possible to suppress a decrease in reception sensitivity. In this example, the second loop element 52 also has an approximately rectangular outer edge, so that the reception sensitivity of the antenna 30 is likely to be improved. Even if the second loop element 52 has a loop shape whose outer edge is different from a substantially rectangular shape, it is possible to suppress a decrease in reception sensitivity.

In this example, the first element 41 and the first loop element 42 have portions extending in the first direction on a straight line parallel to the first direction, so that the reception sensitivity of the antenna 30 is likely to be improved. In the example shown in FIG. 4, the first element 41 has a portion extending on an extension line of the portion 43 of the first loop element 42. In the example shown in FIG. Similarly, since the second element 51 and the second loop element 52 have portions extending in the first direction on a straight line parallel to the first direction, the reception sensitivity of the antenna 30 is likely to be improved. In the example shown in FIG. 4, the second element 51 has a portion extending on an extension line of the portion 53 of the second loop element 52. In the example shown in FIG.

If the first antenna section 40 and the second antenna section 50 are conductors formed on a dielectric substrate (not shown) such as a printed circuit board, it becomes easier to attach the antenna 30 to a vehicle member such as the spoiler 18 described above. . In addition, when the first loop element 42 and the second loop element 52 of the antenna 30 are formed into a substantially rectangular shape, if the direction of the long side of each rectangle extends in the X-axis direction (vehicle width direction), the antenna 30 becomes a spoiler. When attached to the spoiler 18, the antenna 30 can be effectively arranged in the space of the spoiler 18, which is preferable.

FIG. 5 is a plan view showing a second configuration example of the antenna in one embodiment. Descriptions of configurations similar to the first configuration example described above will be omitted in favor of the above description. The antenna 30A shown in FIG. 5 differs from the antenna 30 (FIG. 4) in the shape of the portion where the first element 41 and the second element 51 connect with the waterproof connector 16.

The antenna 30A is connected to a common connection point 21 (specifically, a terminal) of the waterproof connector 16 via the first element 41, the second element 51, and a shared connection element 63. The first element 41 and the second element 51 share a connection element 63 extending from the common connection point 21, and branch from the connection element 63 and extend respectively. Since the first element 41 and the second element 51 each have a part in common, the antenna 30A can receive radio waves in at least three different frequency bands with high sensitivity with a simple configuration.

FIG. 6 is a plan view showing third to seventh configuration examples of the antenna in one embodiment. Descriptions of configurations similar to the first and second configuration examples described above will be omitted in favor of the above description. Although the antennas 31 to 35 shown in FIG. 6 differ from the antenna 30 (FIG. 4) in the shapes of the first loop element 42 and the second loop element 52, they can receive radio waves in at least three different frequency bands with high sensitivity with a simple configuration. Can receive.

In the antenna 31, the inside of the outer edges of the first loop element 42 and the second loop element 52 are filled with a solid conductor. The antenna 32 has four closed loops in which the first loop element 42 and the second loop element 52 are three elements extending in the X-axis direction within each loop element. The antenna 33 has two closed loops in which the first loop element 42 and the second loop element 52 are one element extending in the X-axis direction within each loop element. The antenna 34 has a closed loop including one first loop element 42 and one second loop element 52. In the antenna 35, the first loop element 42 and the second loop element 52 have one open loop, and a pseudo closed loop is formed by capacitive coupling occurring at a location where the first loop element 42 and the second loop element 52 run in parallel near the tip of the open loop.

Next, the antenna capacity and reception voltage of the antenna 30 will be explained using the antenna 30 shown in FIG. 4 as an example. A virtual plane passing through the antenna outlet 12b (waterproof connector 16) formed on the surface of the metal portion 12 and perpendicular to the first direction is defined as a virtual plane 12c.

The distance from the virtual plane 12c to the end of the first antenna section 40 on the first direction side is D ₁ [mm],
The distance from the virtual plane 12c to the end of the second antenna section 50 on the first direction side is D ₂ [mm],
The maximum width of the first loop element 42 in the first direction is H ₁ [mm],
The maximum width of the first loop element 42 in the second direction is L ₁ [mm],
The maximum width of the second loop element 52 in the first direction is H ₂ [mm],
The maximum width of the second loop element 52 in the third direction is L ₂ [mm],
The distance between the first loop element 42 and the second loop element 52 is A _L [mm],
L ₁ +A _L /2 is W ₁ [mm],
L ₂ +A _L /2 is W ₂ [mm],
The antenna capacity of the antenna 30 is C _a [pF],
The antenna capacity of the first antenna section 40 is C _a1 [pF],
The antenna capacity of the second antenna section 50 is C _a2 [pF],
The received voltage of the first antenna section 40 is V _a1 [dBμV _emf ],
The received voltage of the second antenna section 50 is V _a2 [dBμV _emf ],
The received voltage of the antenna 30 is _Va [dBμV _emf ],
k ₁ =1.02×10 ⁻⁴ , k ₂ =7.97×10 ⁻⁵ , k ₃ =2.61×10 ⁻² ,
k ₄ =1.77×10 ⁻² , k ₅ =9.83×10 ⁻⁴ , k ₆ =2.87×10 ⁻¹ ,
l ₁ =3.29×10 ⁻² , l ₂ =6.99×10 ⁻² , l ₃ =2.76×10 ¹ ,
When

という関係が成立する。ここで、
アンプ６０の入力端の電圧をＶ_ｉ［ｄＢμＶ_ｅｍｆ］、
防水コネクタ１６からアンプ６０までの負荷容量をＣ_ｉ［ｐＦ］とするとき、

This relationship is established. here,
The voltage at the input terminal of the amplifier 60 is V _i [dBμV _emf ],
When the load capacity from the waterproof connector 16 to the amplifier 60 is C _i [pF],

という関係が成立する。

This relationship is established.

At this time, the voltage V _i [dBμV _emf ] appearing at the input terminal of the amplifier 60 is

を満たしていれば、アンテナ３０がＡＭ放送波を高感度に受信する上で問題がない。なお、ＡＭ放送波の帯域は５３０ｋＨｚ～１７２０ｋＨｚの範囲である。

If the above is satisfied, there is no problem in the antenna 30 receiving AM broadcast waves with high sensitivity. Note that the band of AM broadcast waves is in the range of 530 kHz to 1720 kHz.

More preferably, the voltage V _i [dBμV _emf ] appearing at the input terminal of the amplifier 60 is

を満たしていれば、アンテナ３０がＡＭ放送波を高感度に受信する上で問題がない。

If the above is satisfied, there is no problem in the antenna 30 receiving AM broadcast waves with high sensitivity.

The waterproof connector 16 and the amplifier 60 may be connected directly, or may be connected via a cable 61. When the antenna device 101 includes a cable 61 that connects the waterproof connector 16 and the amplifier 60, the above load capacitance C _i [pF] is the sum of the input impedance C _AMP [pF] of the amplifier 60 and the impedance C _cb of the cable 61. It can be Japanese.

Note that the above calculation formula for the antenna capacitances C _{a1 and} C _a2 and the coefficients k ₁ to k ₆ of the calculation formula are derived from the graphs of FIGS. 7 to 9, and the calculation formula for the reception voltages V _a1 and V _a2 is The coefficients l ₁ to l ₃ are derived from the graphs in FIGS. 10 to 12.

FIG. 7 shows the antenna capacitance C _a of the antenna 30 and the antenna width W ₁ when the distances D ₁ and D ₂ are fixed to 135 mm when the maximum widths H ₁ and H ₂ are both 10 mm and 110 mm, respectively. It is a graph illustrating the relationship with _W2 . In either case, the antenna capacitance C _a increases as the antenna widths W ₁ and W ₂ increase. FIG. 8 shows the antenna capacitance C _a of the antenna _{30 and the antenna width W 1 when the maximum widths H 1 and H 2} are fixed to 10 mm when the distances D 1 and D ₂ are both 35 mm and 135 mm, respectively. It is a graph illustrating the relationship with _W2 . In either case, the antenna capacitance C _a increases as the antenna widths W ₁ and W ₂ increase. FIG. 9 is a graph illustrating the relationship between the antenna capacitance C _a and the maximum widths H ₁ and H ₂ of the antenna 30 when the distances D ₁ and D ₂ are fixed at 135 mm. The regression equation derived from each point on FIG. 9 corresponds to the calculation equation for the antenna capacitances C _{a1 and} C _a2 described above.

FIG. 10 shows the received voltage V _a of the antenna 30 and the antenna width W ₁ when the distances D ₁ and D ₂ are fixed to 135 mm when the maximum widths H ₁ and H ₂ are both 10 mm and 110 mm, respectively. It is a graph illustrating the relationship with _W2 . In either case, the received voltage V _a hardly depends on the antenna widths W ₁ and W ₂ . FIG. 11 shows the received voltage V _a of the antenna 30 and the antenna width W ₁ when the maximum widths H ₁ and H ₂ are fixed to 10 mm when the distances D ₁ and D ₂ are both 35 mm and 135 mm, respectively. It is a graph illustrating the relationship with _W2 . In either case, the received voltage V _a hardly depends on the antenna widths W ₁ and W ₂ . FIG. 12 is a graph illustrating the relationship between the received voltage V _a of the antenna 30 and the maximum widths H ₁ and H ₂ when the distances D ₁ and D ₂ are fixed at 135 mm. The regression equation derived from each point on FIG. 12 corresponds to the above-described calculation equation for the received voltages V _{a1 and} V _a2 . Note that the received voltage V _a [dBμV _emf ] of the antenna 30 in FIGS. 10 to 12 are all average values in the AM broadcast wave band.

In the antenna according to the present disclosure such as in FIG. 4,
L ₁ +L ₂ +A _L to W,
When
50 [mm]≦W≦1500 [mm],
10 [mm]≦H ₁ ≦300 [mm],
10 [mm]≦H ₂ ≦300 [mm],
15 [mm]≦D ₁ ≦300 [mm],
When 15 [mm]≦D ₂ ≦300 [mm], radio waves in the MF band can be received with high sensitivity. Note that the band of FM broadcast waves is in the range of 88 MHz to 108 MHz, and the band of DAB band III is in the range of 170 MHz to 240 MHz.

95 [mm]≦D ₁ ≦300 [mm],
When 95 [mm]≦D ₂ ≦300 [mm], the antenna gain of the FM broadcast waves is improved, so that the FM broadcast waves can be received with higher sensitivity.

115 [mm]≦D ₁ ≦300 [mm],
When 115 [mm]≦D ₂ ≦300 [mm], the antenna gain of FM broadcast waves improves, and the antenna gain of DAB Band III also improves, so the FM broadcast waves and DAB Band III radio waves are further improved. Can receive with high sensitivity.

In the antenna according to the present disclosure as shown in FIG. 4, D ₁ and D ₂ are preferably the same in terms of receiving VHF band radio waves with high sensitivity, but may be different.

In the antenna according to the present disclosure as shown in FIG. 4, H ₁ and H ₂ are preferably the same in terms of receiving VHF band radio waves with high sensitivity, but may be different.

In the antenna according to the present disclosure as shown in FIG. 4, the maximum width L ₁ is preferably 3.18 times or more and 50 times or less of the maximum width H ₁ in terms of receiving FM broadcast waves with high sensitivity _. More preferably 4.44 times or more and 45 times or less.

In the antenna according to the present disclosure as shown in FIG. 4, the maximum width L ₂ is preferably 0.91 times or more and 25 times or less than the maximum width H ₂ in order to receive DAB band III radio waves with high sensitivity. More preferably, it is 1.79 times or more and 20 times or less of _H2 .

In the antenna according to the present disclosure as shown in FIG. 4, in terms of receiving FM broadcast waves with high sensitivity, 250 [mm]≦L ₁ ≦550 [mm] is preferable, and 250 [mm]≦L ₁ ≦500 [mm] is more preferable. In the antenna according to the present disclosure as shown in FIG. 4, in terms of receiving DAB band III radio waves with high sensitivity, it is preferable that 100 [mm]≦L ₂ ≦250 [mm], and 125 [mm]≦L ₂ ≦225. [mm] is more preferable.

In the antenna according to the present disclosure as shown in FIG. 4, in terms of receiving FM broadcast waves and DAB band III radio waves with high sensitivity, 0 [mm]<A _L ≦240 [mm] is preferable, and 2 [mm]≦ More preferably, A _L ≦240 [mm].

In the antenna according to the present disclosure as shown in FIG. 4, when the distance between the first element 41 and the second element 51 is A, 0[ mm]<A≦240 [mm] is preferable, and 2 [mm]≦A≦240 [mm] is more preferable.

FIG. 13 is a plan view showing an antenna portion 30B of the antenna 30 that contributes to reception of VHF band radio waves. The numerical values in FIG. 13 represent the lengths of the elements [mm]. FIG. 14 shows an example of the measurement results of the average antenna gain of vertically polarized waves in the FM broadcast wave band when the vertical width H _FM and the horizontal width W _FM of the antenna 30 including the antenna portion 30B are changed. FIG. 15 shows an example of the measurement results of the average antenna gain of vertically polarized waves in the DAB band III band when the vertical width H _FM and the horizontal width W _FM of the antenna 30 including the antenna portion 30B are changed. FIG. 16 is a graph showing the measurement results of FIG. 14. FIG. 17 is a graph showing the measurement results of FIG. 15. Note that the vertical width H _FM =0 corresponds to a pattern in which no loop is provided in the antenna portion 30B of FIG. 13 .

According to FIGS. 14 to 17, when the vertical width H _FM and the horizontal width W _FM of the antenna portion 30B are adjusted, the average antenna gain in the FM broadcast wave band changes greatly, but the average antenna gain in the DAB band III band changes significantly. There was little change.

The range above the threshold "-11dB" where FM broadcast waves can be received with relatively high sensitivity is
110 [mm] ≧ H _FM ≧ 10 [mm]
550 [mm] ≧ W _FM ≧ 250 [mm]
It became.

The range above the threshold "-10dB" where FM broadcast waves can be received with relatively high sensitivity is
90 [mm] ≧ H _FM ≧ 10 [mm]
500 [mm] ≧ W _FM ≧ 250 [mm]
It became.

FIG. 18 shows an example of the measurement results of the average antenna gain in the FM broadcast wave band when the aspect ratio of the antenna 30 including the antenna portion 30B is changed. The antenna gain exceeded the threshold value of "-11 dB" in the aspect ratio displayed in the satin cell. The antenna gain exceeded the threshold value of "-10 dB" at the aspect ratio indicated by the diagonally shaded cells.

FIG. 19 is a plan view showing an antenna portion 30C of the antenna 30 that contributes to reception of DAB band III radio waves. The numerical values in FIG. 19 represent the lengths of the elements [mm]. FIG. 20 shows an example of the measurement results of the average antenna gain of vertically polarized waves in the FM broadcast wave band when the vertical width H _DAB and the horizontal width W _DAB of the antenna including the antenna portion 30C are changed. FIG. 21 shows an example of the measurement results of the average antenna gain of vertically polarized waves in the DAB band III band when the vertical width H _DAB and the horizontal width W _DAB of the antenna including the antenna portion 30C are changed. FIG. 22 is a graph showing the measurement results of FIG. 20. FIG. 23 is a graph showing the measurement results of FIG. 21. Note that the vertical width H _DAB =0 corresponds to a pattern in which no loop is provided in the antenna portion 30C in FIG. 19 .

According to FIGS. 20 to 23, when the vertical width H _DAB and the horizontal width W _DAB of the antenna portion 30C are adjusted, the average antenna gain in the DAB band III band changes greatly, but the average antenna gain in the FM broadcast wave band There was little change.

The range above the threshold "-14 dB" where DAB band III radio waves can be received with relatively high sensitivity is
110 [mm] ≧ H _DAB ≧ 10 [mm]
250 [mm] ≧ W _DAB ≧ 100 [mm]
It became.

The range above the threshold "-13 dB" where DAB band III radio waves can be received with relatively high sensitivity is
70 [mm] ≧ H _DAB ≧ 10 [mm]
225 [mm] ≧ W _DAB ≧ 125 [mm]
It became.

FIG. 24 shows an example of the measurement results of the average antenna gain in DAB band III when the aspect ratio of the antenna 30 including the antenna portion 30C is changed. The antenna gain exceeded the threshold value of "-14dB" in the aspect ratio displayed in the satin cell. The antenna gain exceeded the threshold value of "-13 dB" at the aspect ratio indicated by the diagonally shaded cells.

FIG. 25 shows an example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the loop vertical width of the antenna 30 in FIG. 4 is changed. The dimensions of each element during measurement are shown in FIGS. 13 and 19. When the vertical widths of the antenna portions 30B and 30C were made the same and varied, the smaller the vertical width, the higher the sensitivity.

The range is above the threshold "-11 dB" for receiving FM broadcast waves with relatively high sensitivity, and above the threshold "-14 dB" for receiving DAB band III radio waves with relatively high sensitivity.
90[mm]≧H _FM ≧0[mm]
20 [mm] ≧ H _DAB ≧ 0 [mm]
It became.

The range is at least -10dB, which is the threshold for receiving FM broadcast waves with relatively high sensitivity, and at least -13dB, which is the threshold for receiving DAB Band III radio waves with relatively high sensitivity.
60 [mm] ≧ H _FM ≧0 [mm]
10 [mm] ≧ H _DAB ≧0 [mm]
It became.

FIG. 26 shows an example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the distance between the loop elements of the antenna 30 in FIG. 4 is changed. The dimensions of each element during measurement are shown in FIGS. 13 and 19.

The range above the threshold "-11dB" where FM broadcast waves can be received with relatively high sensitivity is
360 [mm] ≧ A _L ≧ 2 [mm]
It became.

The range above the threshold "-14 dB" where DAB band III radio waves can be received with relatively high sensitivity is
240 [mm] ≧ A _L ≧ 2 [mm]
It became.

FIG. 27 shows an example of the measurement results of the average antenna gain in the FM broadcast wave band and the DAB band III band when the distances D ₁ and D ₂ from the virtual plane 12c are changed for the antenna 30 in FIG. 4. . The dimensions of each element during measurement are shown in FIGS. 13 and 19.

In both the FM broadcast wave band and Band III band, the average antenna gain improved as the distance from the virtual plane 12c increased. In order to obtain a gain of -10 dB or more in the FM broadcast wave band, it was necessary to separate them by 90 mm or more. In Band III, there was little change in average antenna gain even when separated by 80 mm or more. Assuming that the maximum width of the spoiler 18 is 300 mm, the preferable range is considered to be as follows.

The range above the threshold "-10dB" where FM broadcast waves can be received with relatively high sensitivity is
300 [mm] ≧ D _1, D ₂ ≧ 115 [mm]
It became.

The range above the threshold "-11dB" where FM broadcast waves can be received with relatively high sensitivity is
300 [mm] ≧ D _1, D ₂ ≧ 95 [mm]
It became.

The range above the threshold "-14 dB" where Band III radio waves can be received with relatively high sensitivity is
300 [mm] ≧ D _1, D ₂ ≧ 115 [mm]
It became.

FIG. 28 shows an example of the measurement results of the average antenna gain in the UHF band of the antenna 30 in FIG. 4. The dimensions of each element during measurement are shown in FIGS. 13 and 19. It was confirmed that it can be used sufficiently for reception of the UHF band. In other words, in addition to AM broadcast waves, FM broadcast waves, and DAB broadcast waves, terrestrial digital broadcast waves could also be sufficiently received. Note that the band of digital terrestrial broadcast waves is in the range of 470 MHz to 720 MHz, and all measurement results for the UHF band are average antenna gains in horizontal polarization.

Although the embodiments have been described above, the technology of the present disclosure is not limited to the above embodiments. Various modifications and improvements such as combinations and substitutions with part or all of other embodiments are possible.

For example, the antenna device according to the present disclosure is not limited to being installed on a vehicle member made of resin; for example, if it can transmit and receive radio waves with a desired sensitivity, it can be installed on a vehicle member made of a material other than resin. may be installed.

10 Lift gate 11 Window glass 12 Metal part 12a Edge 12b Antenna outlet 12c Virtual plane 13 Outer cover 14 Inner cover 16 Waterproof connector 17 High mount stop lamp 18 Spoiler 20 Hole 21 Connection point 30-35 Antenna 40 First antenna part 41 First element 42 First loop element 43-46 section 50 Second antenna section 51 Second element 52 Second loop element 53-56 section 60 Amplifier 61 Cable 63 Connection element 101 Antenna device

Claims (23)

An antenna device that is provided on a vehicle member attached to a vehicle body and receives radio waves in a first frequency band, radio waves in a second frequency band, and radio waves in a third frequency band,
A power supply unit,
an antenna having a first antenna section electrically connected to the power feeding section; and a second antenna section electrically connected to the power feeding section;
an amplifier electrically connected to the power feeding section,
The first antenna section includes a first element including a portion extending in a first direction, and a first loop element having a loop-shaped outer edge and connected to an end of the first element opposite to the power feeding section. and has
The second antenna section includes a second element including a portion extending in the first direction, and a second loop having a loop-shaped outer edge connected to an end of the second element opposite to the power feeding section. It has an element,
The first loop element includes a portion extending in the first direction and a portion extending in a second direction different from the first direction,
The second loop element includes a portion extending in the first direction and a portion extending in a third direction opposite to the second direction,
The antenna device, wherein the first loop element and the second loop element are located apart from each other. The first direction is a direction away from the metal part of the vehicle body,
The antenna device according to claim 1, wherein the first element and the second element intersect with an edge of the metal part when viewed from a normal direction of a horizontal plane with the vehicle member attached to the vehicle body. . When defining a virtual plane passing through the antenna outlet formed on the surface of the metal part and perpendicular to the first direction,
The distance from the virtual plane to the end of the first antenna section on the first direction side is D ₁ [mm],
The distance from the virtual plane to the end of the second antenna section on the first direction side is D ₂ [mm],
The maximum width of the first loop element in the first direction is H ₁ [mm],
The maximum width of the first loop element in the second direction is L ₁ [mm],
The maximum width of the second loop element in the first direction is H ₂ [mm],
The maximum width of the second loop element in the third direction is L ₂ [mm],
The distance between the first loop element and the second loop element is A _L [mm],
L ₁ +A _L /2 is W ₁ [mm],
L ₂ +A _L /2 is W ₂ [mm],
The antenna capacitance of the first antenna section is C _a1 [pF],
The antenna capacitance of the second antenna section is C _a2 [pF],
The antenna capacity of the antenna is C _a [pF],
The received voltage of the first antenna section is V _a1 [dBμV _emf ],
The received voltage of the second antenna section is V _a2 [dBμV _emf ],
The received voltage of the antenna is V _a [dBμV _emf ],
k ₁ =1.02×10 ⁻⁴ , k ₂ =7.97×10 ⁻⁵ , k ₃ =2.61×10 ⁻² ,
k ₄ =1.77×10 ⁻² , k ₅ =9.83×10 ⁻⁴ , k ₆ =2.87×10 ⁻¹ ,
l ₁ =3.29×10 ⁻² , l ₂ =6.99×10 ⁻² , l ₃ =2.76×10 ¹ ,
When

and
The voltage at the input terminal of the amplifier is V _i [dBμV _emf ],
When the load capacitance from the power supply unit to the amplifier is C _i [pF],

and
The voltage V _i [dBμV _emf ] is

The antenna device according to claim 2, which satisfies the following. The voltage V _i [dBμV _emf ] is

The antenna device according to claim 3, which satisfies the following. comprising a cable connecting the power feeding section and the amplifier,
The antenna device according to claim 3 or 4, wherein the load capacitance C _i [pF] is the sum of the input impedance C _AMP [pF] of the amplifier and the impedance C _cb of the cable. When defining a virtual plane passing through the antenna outlet formed on the surface of the metal part and perpendicular to the first direction,
The distance from the virtual plane to the end of the first antenna section on the first direction side is D ₁ [mm],
The distance from the virtual plane to the end of the second antenna section on the first direction side is D ₂ [mm],
The maximum width of the first loop element in the first direction is H ₁ [mm],
The maximum width of the first loop element in the second direction is L ₁ [mm],
The maximum width of the second loop element in the first direction is H ₂ [mm],
The maximum width of the second loop element in the third direction is L ₂ [mm],
The distance between the first loop element and the second loop element is A _L [mm],
L ₁ +L ₂ +A _L is W [mm],
When
50 [mm]≦W≦1500 [mm],
10 [mm]≦H ₁ ≦300 [mm],
10 [mm]≦H ₂ ≦300 [mm],
15 [mm]≦D ₁ ≦300 [mm],
The antenna device according to any one of claims ₂ to 5, wherein 15 [mm]≦D 2 ≦300 [mm]. When defining a virtual plane passing through the antenna outlet formed on the surface of the metal part and perpendicular to the first direction,
The distance from the virtual plane to the end of the first antenna section on the first direction side is D ₁ ,
The distance from the virtual plane to the end of the second antenna section on the first direction side is D ₂ ,
When
The antenna device according to any one of claims 2 to 6, wherein the D ₁ and the D ₂ are the same. The maximum width of the first loop element in the first direction is H ₁ ,
The maximum width of the second loop element in the first direction is _H2 ,
When
The antenna device according to any one of claims 1 to 7, wherein the H ₁ and the H ₂ are the same. 9. The maximum width _L1 of the first loop element in the second direction is 3.18 times or more and 50 times or less the maximum width _H1 of the first loop element in the first direction. The antenna device according to any one of the items. The maximum width _L2 of the second loop element in the third direction is 0.91 times or more and 25 times or less the maximum width _H2 of the second loop element in the first direction. The antenna device according to any one of the items. The maximum width of the first loop element in the second direction is L ₁ ,
When the maximum width of the second loop element in the second direction is _L2 ,
250 [mm]≦L ₁ ≦550 [mm],
The antenna device according to any one of claims 1 to 10, wherein 100 [mm]≦L ₂ ≦250 [mm]. When the distance between the first loop element and the second loop element is A _L ,
The antenna device according to any one of claims 1 to 11, wherein 0 [mm]<A _L ≦240 [mm]. The antenna device according to any one of claims 1 to 12, wherein the first element and the second element are connected to different connection points in the power feeding section. The antenna device according to any one of claims 1 to 12, wherein the first element and the second element are connected to a common connection point of the power feeding unit via a shared connection element. The antenna device according to any one of claims 1 to 14, wherein the first direction is substantially orthogonal to the second direction and the third direction. The antenna device according to any one of claims 1 to 15, wherein the first loop element and the second loop element have substantially rectangular outer edges. When the distance between the first element and the second element is A,
The antenna device according to any one of claims 1 to 16, wherein 0 [mm]<A≦240 [mm]. The first element and the first loop element have a portion extending in the first direction on a straight line parallel to the first direction,
The antenna device according to any one of claims 1 to 17, wherein the second element and the second loop element have a portion extending in the first direction on a straight line parallel to the first direction. The first frequency band is an AM broadcast wave band,
The second frequency band is a band of FM broadcast waves,
The antenna device according to any one of claims 1 to 18, wherein the third frequency band is a band III of DAB. The antenna device according to claim 19, wherein the antenna device receives radio waves in a fourth frequency band, and the fourth frequency band is a band of digital terrestrial television broadcast waves. The antenna device according to any one of claims 1 to 20, wherein the power feeding section, the first antenna section, and the second antenna section are conductors formed on a dielectric substrate. The antenna device according to any one of claims 1 to 21, wherein the vehicle member is made of resin. The antenna device according to any one of claims 1 to 22, wherein the vehicle member is a spoiler.

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