JP2021064942A - Glass antenna - Google Patents

Abstract

To provide a glass antenna capable of improving the sensitivity of sending and receiving electric waves of ITS.SOLUTION: The glass antenna, installed on a window glass of a vehicle and sending and receiving electric waves of ITS, includes: a connection terminal having a power supply side contact and a ground side contact; a first conductor connected with the power supply side contact and the ground side contact; and a loop-shaped second conductor connected with the power supply side contact and the ground side contact.SELECTED DRAWING: Figure 2

Description

The present invention relates to a glass antenna provided on a window glass of a vehicle by transmitting and receiving ITS radio waves.

ITS (Intelligent Traffic System) such as ETC is used for transmitting and receiving vehicle-to-vehicle communication and road-to-vehicle communication by two-way communication, and the vehicle is provided with a glass antenna for transmitting and receiving this radio wave (for example). , Patent Document 1).

JP-A-2017-5711

However, there is room for improvement in improving the sensitivity of transmitting and receiving radio waves of ITS, and further improvement has been desired. The present invention has been made to solve this problem, and an object of the present invention is to provide a glass antenna capable of improving the sensitivity of transmitting and receiving radio waves of ITS.

The first glass antenna according to the present invention is a glass antenna provided on the window glass of a vehicle to transmit and receive ITS radio waves, and is a connection terminal having a power feeding side contact and a grounding side contact, and the power feeding side contact and the grounding side contact. It includes a first conductor connected to the ground side contact, and a loop-shaped second conductor connecting the power feeding side contact and the ground side contact.

The second glass antenna according to the present invention is a glass antenna provided on the window glass of a vehicle to transmit and receive ITS radio waves, and is a connection terminal having a power feeding side contact and a grounding side contact, and the power feeding side contact and the grounding side contact. A first conductor connected to the ground side contact, a loop-shaped second conductor connecting the power feeding side contact and the ground side contact, and sharing a part of the first conductor are provided. ing.

In the glass antenna, the first conductor can be formed in a loop shape connecting the feeding side contact and the grounding side contact.

In the glass antenna, the first conductor can be configured to adjust the sensitivity of transmitting and receiving the radio wave, and the second conductor can be configured to adjust the impedance matching characteristic. ..

In the glass antenna, the horizontal width of the first conductor is longer than the horizontal width of the second conductor, and the vertical width of the first conductor is above and below the second conductor. It can be formed shorter than the width in the direction.

In the glass antenna, both the vertical length of the first conductor and the vertical length of the second conductor correspond to 0.01 to 0.2 times the wavelength of the radio wave. It can be done.

In the glass antenna, the total length of the second conductor and the distance between the two contacts can be a length corresponding to 0.5 to 0.9 times the wavelength of the radio wave.

In the glass antenna, the total length of the first conductor and the distance between the two contacts can be set to a length corresponding to 0.9 to 1.3 times the wavelength of the radio wave.

The glass antenna can be arranged within a range of 50 mm downward from the upper edge of the window glass.

In the glass antenna, the connection terminal can be arranged at a position shifted in the horizontal direction from the horizontal center of the first conductor and the second conductor.

In the glass antenna, at least a part of the first conductor can be arranged above the connection terminal, and at least a part of the second conductor can be arranged below the connection terminal.

In the glass antenna, the impedance of the transmission line connected to the connection terminal can be 40 to 80Ω.

According to the glass antenna according to the present invention, the sensitivity of transmitting and receiving radio waves of ITS can be improved.

It is a partial plan view of the window glass in which the glass antenna is arranged in this invention. It is a top view which shows the 1st glass antenna. It is a top view which shows the 2nd glass antenna. It is a top view which shows the 3rd glass antenna. It is a top view which shows the modification of the 3rd glass antenna. It is a top view which shows the modification of the 3rd glass antenna. It is a top view which shows the 4th glass antenna. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view which shows another example of the glass antenna which concerns on this invention. It is a top view of the glass antenna which concerns on a comparative example. It is a top view of the glass antenna which concerns on Example 9. FIG. It is a top view of the glass antenna which concerns on Example 10. It is a top view of the glass antenna which concerns on Example 11. FIG. It is a top view of the glass antenna which concerns on Example 12. FIG. It is an impedance curve of a frequency of 700 to 800 MHz, and is the figure which shows the impedance of 760 MHz of Example 13, Comparative Examples 1 and 2. It is a graph which calculated the loss of the antenna sensitivity due to the impedance mismatch in Example 13 and Comparative Examples 1 and 2. It is a top view of the glass antenna which concerns on Example 14. It is a top view of the glass antenna which concerns on Example 15. FIG. It is a top view of the glass antenna which concerns on Example 16. It is a top view of the glass antenna which concerns on Example 17.

Hereinafter, embodiments of the glass antenna according to the present invention will be described with reference to the drawings. FIG. 1 is a plan view showing a window glass of a vehicle in which a first glass antenna is arranged. The target window glass is not particularly limited as long as it is a vehicle window glass, and can be arranged in any of a windshield, a rear glass, a side glass, and the like. In this embodiment, four types of glass antennas, that is, the first, second, third, and fourth glass antennas 101 to 104 will be described in order (FIG. 1 shows the first glass antenna 101). ing). Hereinafter, the window glass 200 will be described first, and then the glass antennas 101 to 104 will be described in detail.

<1. Glass plate ＞
First, the window glass 200 in which the glass antennas 101 to 104 are arranged will be described. As the window glass 200, a known glass plate for automobiles can be used. For example, as the glass plate, heat ray absorbing glass, general clear glass, dark privacy glass or green glass, or UV green glass may be used. However, such glass plates need to achieve visible light transmittance in line with the safety standards of the country in which the vehicle is used. For example, the solar radiation absorption rate, the visible light transmittance, and the like can be adjusted so as to satisfy the safety standard. An example of the composition of the clear glass and an example of the composition of the heat ray absorbing glass are shown below.

(Clear glass)
SiO ₂ : 70 to 73% by mass
Al ₂ O ₃ : 0.6 to 2.4% by mass
CaO: 7-12% by mass
MgO: 1.0 to 4.5% by mass
R ² O: 13 to 15% by mass (R is an alkali metal)
Total iron oxide converted to Fe ₂ O _{3 (T-Fe 2} O ₃ ): 0.08 to 0.14% by mass

(Heat ray absorbing glass)
The composition of the heat-absorbing glass, for example, based on the composition of the clear glass, the proportion of the total iron oxide in terms of _{Fe 2 O 3 (T-Fe} 2 O 3) and 0.4 to 1.3 wt%, CeO ₂ ratio as 0-2 mass%, the proportion of TiO ₂ and 0 to 0.5 wt%, framework component of the glass (mainly, SiO ₂ and Al ₂ O ₃₎ to T-Fe ₂ O _3, CeO _The composition can be reduced by the amount of increase in 2 and TiO _2.

The type of glass plate is not limited to clear glass or heat ray absorbing glass, and can be appropriately selected depending on the embodiment. For example, the glass plate may be an acrylic-based or polycarbonate-based resin window.

Further, the window glass 200 is appropriately formed into a curved shape. In addition to being composed of a single glass plate, such a window glass 200 may be a laminated glass in which an interlayer film such as resin is sandwiched between two pieces of glass. When the window glass is a single glass plate, the glass antenna is arranged on the inner surface of the window glass 200. On the other hand, when the window glass 200 is a laminated glass, the glass antennas 101 to 104 are arranged on the inner surface of the glass plate inside the vehicle, and the glass antennas 101 to 104 are arranged between the two glass plates. can do.

<2. 1st glass antenna ＞
Next, the first glass antenna 101 will be described with reference to FIG. FIG. 2 is a plan view showing the first glass antenna. The first glass antenna 101 includes a connection terminal 1, a first conductor 2 extending in a loop shape, and a second conductor 3 extending in a loop shape, which are arranged on the inner surface of the window glass 200. Hereinafter, these will be described in detail. In the following, the description will be made according to the direction on the paper of FIG. 2, but the present invention is not limited to this direction.

<2-1. Connection terminal>
The connection terminal 1 includes a ground contact 11 and a power feeding side contact 12 formed in a rectangular shape, and these are arranged at positions separated in the horizontal direction. Then, these contacts 11 and 12 are connected to a connection terminal (not shown) provided inside the vehicle, and are connected to a transmitter / receiver for ITS (not shown) provided inside the vehicle by a coaxial cable (not shown). ing.

In the following, for convenience of explanation, the upper right corners, the upper left corner, the lower left corner, and the lower right corner of FIG. 2 are the first corner portions 111, 121 and the second corner portions 112, 122, respectively, at the contacts 11 and 12, respectively. It will be referred to as a third corner portion 113, 123 and a fourth corner portion 114, 124.

<2-2. First conductor>
The first conductor 2 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The first conductor 2 is formed by five portions 21 to 25. That is, the first portion 21 extending horizontally to the left from the third corner portion 113 of the ground contact side contact 11, the second portion 22 extending upward from the left end portion of the first portion 21, and the right from the upper end of the second portion 22. A third portion 23 extending horizontally in the direction, a fourth portion 24 extending slightly downward from the right end of the third portion 23, and a second portion of the power feeding side contact 12 extending horizontally from the lower end of the fourth portion 24 to the left. It is formed by a fifth portion 25 connected to a corner portion 121. The line width of the first conductor 2 can be, for example, 0.3 to 5 mm. This point is the same for the second conductor 3, which will be described later.

As shown in FIG. 2, the upper end of the second portion 22 is arranged above both contacts 11 and 12, whereby the third portion 23 extends horizontally above both contacts 11 and 12. .. Further, the third portion 23 extends to the right side beyond the feeding side contact 12.

As described above, the first conductor 2 is formed so that the width X11 in the horizontal direction is long and the width Y11 in the vertical direction is short. Further, the first conductor 2 is mainly arranged so as to pass above the connection terminal 1.

Here, the loop length L11 of the first conductor 2 will be described. The loop length L11 referred to here includes the total length of the first to fifth portions 21 to 25 of the first conductor 2, as well as the distance between the contacts 11 and 12. The distance between the contacts 11 and 12 is the distance between both ends of the first conductor 2 passing through the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the fourth corner 124 of the power feeding side contact 12 and the length from the fourth corner 124 to the first corner 121 of the feeding side contact 12. The sum of the sum and the sum is defined as the loop length L11 of the first conductor 2, which is the sum of the lengths of the first to fifth parts 21 to 25.

The loop length L11 of the first conductor is preferably set as shown in the following equation (1).
0.9 * αλ ≤ L11 ≤ 1.3 * αλ (1)
Here, λ is the wavelength of the ITS radio wave, and α is the wavelength shortening rate of the glass plate. The wavelength shortening rate α of the glass plate varies depending on the composition of the glass plate and the like, but is, for example, about 0.5 to 0.7. The meanings of the above parameters are the same in the equations described later.

By setting the loop length L11 of the first conductor 2 in this way, the sensitivity of transmitting and receiving radio waves can be improved. The loop length L11 of the first conductor 2 is more preferably 0.95 * αλ or more and 1.25 * αλ or less.

Further, the maximum length of the first conductor 2 in the vertical direction, that is, in this example, the length Y11 of the second portion 22 is preferably set as shown in the following formula (2).
0.01 * αλ ≤ Y11 ≤ 0.2 * αλ (2)

<2-3. Second conductor>
The second conductor 3 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The second conductor 3 is formed by six portions 31 to 36. That is, the first portion 31 extending horizontally to the left from the third corner portion 113 of the ground contact side contact 11, the second portion 32 extending downward from the left end portion of the first portion 31, and the lower end to the right of the second portion 32. A third part 33 extending horizontally in the direction, a fourth part 34 extending upward from the right end of the third part 33, a fifth part 35 extending horizontally from the upper end of the fourth part 34 to the left, and a fifth part thereof. It is formed by a sixth portion 36 that extends slightly upward from the right end portion of the portion 35 and is connected to the third corner portion 123 of the power feeding side contact 12.

As shown in FIG. 2, the first portion 31 is common to a part of the first portion 21 of the first conductor 2, and the area from the right end portion to the vicinity of the center of the first portion 21 of the first conductor 2 is formed. It also serves as the first portion 31 of the second conductor 3. The third portion 33 extends in the vertical direction below the ground contact side contact 11, and the upper end portion of the third portion 33 is close to the ground contact side contact 11. The right end of the fifth portion 35 extends below the third corner portion 123 of the power feeding side contact 12.

As described above, the width X12 in the horizontal direction of the second conductor 3 is shorter than the width X11 of the first conductor 2, and the width Y12 in the vertical direction is longer than the width Y11 of the first conductor 2. .. Further, the second conductor 3 is arranged so as to pass below the connection terminal 1.

Here, the loop length L12 of the second conductor 3 will be described. The loop length L12 referred to here includes the total length of the first to sixth portions 31 to 36 of the second conductor 3, as well as the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the third corner 123 of the power feeding side contact 12 is shown, and the lengths of the first to sixth parts 31 to 36 are added to this. Is defined as the loop length L12 of the second conductor.

The loop length L12 of the second conductor is preferably set as shown in the following equation (3).
0.5 * αλ ≤ L12 ≤ 0.9 * αλ (3)

By setting the loop length L12 of the second conductor 3 in this way, the impedance matching characteristic can be improved. The loop length L12 of the second conductor is more preferably 0.6 * αλ or more and 0.8 * αλ or less.

Further, the maximum length of the second conductor 3 in the vertical direction, that is, in this example, the length Y12 of the second portion 32 is preferably set as shown in the following formula (4).
0.01 * αλ ≤ Y12 ≤ 0.2 * αλ (4)

<3. 2nd glass antenna ＞
Next, the second glass antenna 102 will be described with reference to FIG. Since the second glass antenna 102 has the same configuration of the connection terminal 1 as the first glass antenna 101, the description thereof will be omitted. Therefore, in the following, these conductors will be mainly described.

<3-1. First conductor>
The first conductor 4 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The first conductor 4 is formed by five portions 41 to 45. That is, from the first portion 41 extending horizontally to the left from the second corner portion 112 of the ground contact side contact 11, the second portion 42 extending slightly upward from the left end portion of the first portion 41, and the upper end of the second portion 42. A third portion 43 extending horizontally to the right, a fourth portion 44 extending slightly downward from the right end of the third portion 43, and a fourth portion 44 extending horizontally from the lower end of the fourth portion 44 to the left, and the feeding side contact 12 It is formed by a fifth portion 45 connected to the first corner portion 121.

As shown in FIG. 3, the third portion 43 extends horizontally above both the contacts 11 and 12, and extends to the right beyond the feeding side contact 12.

As described above, the first conductor 4 of the second glass antenna 102 has the same width in the horizontal direction as the first conductor 2 of the first glass antenna 101, but is formed to have a shorter width in the vertical direction. There is.

The loop length L21 of the first conductor 4 is calculated in the same manner as the first glass antenna 101, and includes the total length of the first to fifth portions 41 to 45 and the distance between the contacts 11 and 12. The distance between the contacts 11 and 12 is the length from the second corner 112 of the ground contact 11 to the first corner 121 of the power feeding side contact 12, and the first to fifth parts 41 to 45. Is defined as the loop length L21 of the first conductor 4.

Then, the loop length L21 of the first conductor 4 is preferably set by the above-mentioned equation (1) in the same manner as L11 (in the equation (1), L21 is applied instead of L11). Further, a more preferable range is also set in the same manner. This point is the same for the vertical length Y21 of the first conductor 4, and can be applied to the formula (2).

<3-2. Second conductor>
The second conductor 5 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The second conductor 5 is formed by four portions 51 to 54. That is, from the first portion 51 extending horizontally to the left from the third corner portion 113 of the ground contact side contact 11, the second portion 52 extending slightly downward from the left end portion of the first portion 51, and the lower end of the second portion 52. It is formed by a third portion 53 extending horizontally to the right and a fourth portion 54 extending upward from the right end portion of the third portion 53 and connected to the third corner portion 123 of the power feeding side contact 12.

As shown in FIG. 3, the first portion 51 is formed shorter than the first portion 41 of the first conductor 4. The third portion 53 extends beyond the ground side contact 11 and further extends below the third corner portion 123 of the power feeding side contact 12.

As described above, the width X22 in the horizontal direction of the second conductor 5 is shorter than that of the first conductor 4, and the width Y22 in the vertical direction is formed to be slightly longer than that of the first conductor 4.

Here, the loop length L22 of the second conductor 5 will be described. The loop length L22 referred to here includes the total length of the first to fourth portions 51 to 54 of the second conductor 5, as well as the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the third corner 123 of the power feeding side contact 12 plus the lengths of the first to fourth parts 51 to 54 is added. It is defined as the loop length L22 of the second conductor 5.

Then, the loop length L22 of the second conductor 5 is preferably set by the above-mentioned formula (3) as in the case of L12 (in the formula (3), L22 is applied instead of L12). Further, a more preferable range is also set in the same manner. This point is the same for the length Y22 of the second conductor 5 in the vertical direction, and can be applied to the formula (4).

<4. 3rd glass antenna ＞
Next, the third glass antenna 103 will be described with reference to FIG. Since the third glass antenna 103 has the same configuration of the connection terminal 1 as the first glass antenna 101, the description thereof will be omitted. Therefore, in the following, these conductors 6 and 7 will be mainly described.

<4-1. First conductor>
The first conductor 6 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The first conductor 6 is formed by six portions 61 to 66. That is, from the first portion 61 extending downward from the third corner portion 113 of the ground contact side contact 11, the second portion 62 extending horizontally from the lower end portion of the first portion 61 to the left, and the left end portion of the second portion 62. A third part 63 extending upward, a fourth part 64 extending horizontally from the upper end of the third part 63 to the right, a fifth part 65 extending slightly downward from the right end of the fourth part 64, and a fifth part. It is formed by a sixth portion 66 extending horizontally from the lower end portion of 65 to the left and connected to the first corner portion 121 of the power feeding side contact 12.

As shown in FIG. 4, the upper end of the third portion 63 is arranged above both contacts 11 and 12, whereby the fourth portion 64 extends horizontally above both contacts 11 and 12. .. Further, the fourth portion 64 extends to the right side beyond the feeding side contact 12.

As described above, the first conductor 6 is formed so that the width X31 in the horizontal direction is long and the width Y31 in the vertical direction is short. Further, the first conductor 6 is mainly arranged so as to pass above the connection terminal 1.

Here, the loop length L31 of the first conductor 6 will be described. The loop length L31 referred to here includes the total length of the first to sixth portions 61 to 66 of the first conductor 6, as well as the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the fourth corner 124 of the power feeding side contact 12 and the length from the fourth corner 124 to the first corner 121 of the feeding side contact 12. The sum of the sum and the lengths of the first to sixth parts 61 to 66 is defined as the loop length L31 of the first conductor 6.

Then, the loop length L31 of the first conductor 6 is preferably set by the above-mentioned formula (1) as in the case of L11 (in the formula (1), L31 is applied instead of L11). Further, a more preferable range is also set in the same manner. This point is the same for the length Y31 of the first conductor 6 in the vertical direction, and can be applied to the formula (2).

<4-2. Second conductor>
The second conductor 7 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The second conductor 7 is formed by seven portions. That is, from the first portion 71 extending downward from the third corner portion 113 of the ground contact side contact 11, the second portion 72 extending horizontally from the lower end portion of the first portion 71 to the left, and the left end portion of the second portion 72. A third part 73 extending downward, a fourth part 74 extending horizontally from the lower end of the third part 73 to the right, a fifth part 75 extending upward from the right end of the fourth part 74, and a fifth part 75. It is formed by a sixth portion 76 extending horizontally from the upper end portion of the sixth portion to the right, and a seventh portion 77 extending upward from the right end portion of the sixth portion 76 and connected to the lower side of the power feeding side contact 12.

As shown in FIG. 4, the first portion 71 is common to the first portion 61 of the first conductor 6. Further, the second portion 72 is partly in common with the second portion 62 of the first conductor 6, and the portion from the right end portion to the vicinity of the center of the second portion 62 of the first conductor 6 is the second conductor 7. It also serves as the second part 72. The fifth portion 75 extends in the vertical direction below the ground contact side contact 11, and the upper end portion of the fifth portion 75 is close to the ground side contact 11. The right end of the sixth portion 76 extends below the third corner portion 123 of the power feeding side contact 12.

As described above, the width X32 in the horizontal direction of the second conductor 7 is shorter than that of the first conductor 6, and the width Y32 in the vertical direction is longer than that of the first conductor 7. Further, the second conductor 7 is arranged so as to pass below the connection terminal 1.

Here, the loop length L32 of the second conductor 7 will be described. The loop length L32 referred to here includes the total length of the first to seventh portions 71 to 77 of the second conductor 7, as well as the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the upper end of the seventh portion connected to the lower side of the power feeding side contact 12 is the length of the first to seventh portions 71 to 74. Is defined as the loop length L32 of the second conductor 7.

Then, the loop length L32 of the second conductor 7 is preferably set by the above-mentioned formula (3) as in the case of L12 (in the formula (3), L32 is applied instead of L12). Further, a more preferable range is also set in the same manner. This point also applies to the vertical length Y32 of the second conductor 7, and can be applied to the equation (4).

In the third glass antenna 103, for example, as shown in FIG. 5, the length of the third portion 63 of the first conductor 6 is set to substantially the same length as that of the second portion 62, and the length is adjusted accordingly. It is also possible to adjust the length of the fifth portion 75 of the second conductor 7. Further, the third portion 73 extends slightly to the right of the example of FIG. 4, that is, downward from substantially the center of the second portion 62 of the first conductor 6.

Further, as shown in FIG. 6, in addition to the first and second conductors 6 and 7, a third conductor 60 may be provided.

As shown in FIG. 6, the third conductor 60 is formed by arranging linear conductors in an L shape and is formed by two portions 67 and 68. That is, it is formed by a first portion 67 extending horizontally to the left from the third corner portion 113 of the ground contact side contact 11, and a second portion 68 extending downward from the left end portion of the first portion 67. The first portion 67 has the same length as the second portion 72 of the second conductor 7, and the lower end portion of the second portion 68 is connected to the left end portion of the second portion 72 of the second conductor 7. .. In this way, the third conductor 60 is connected to both the first conductor 6 and the second conductor 7.

<5. 4th glass antenna ＞
Next, the fourth glass antenna 104 will be described with reference to FIG. 7. Since the configuration of the connection terminal 1 of the fourth glass antenna 104 is the same as that of the first glass antenna 101, the description thereof will be omitted. Therefore, in the following, these conductors 8 and 9 will be mainly described.

<5-1. First conductor>
The first conductor 8 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The first conductor 8 is formed by six portions 81-86. That is, from the first portion 81 extending downward from the third corner portion 113 of the ground contact side contact 11, the second portion 82 extending horizontally from the lower end portion of the first portion 81 to the left, and the left end portion of the second portion 82. A third part 83 extending upward, a fourth part 84 extending horizontally to the right from the upper end of the third part 83, a fifth part 85 extending slightly downward from the right end of the fourth part 84, and a fifth part. It is formed by a sixth portion 86 extending horizontally from the lower end portion of the 85 to the left and connected to the first corner portion 121 of the power feeding side contact 12.

As shown in FIG. 7, the upper end of the third portion 83 is arranged above both contacts 11 and 12, whereby the fourth portion 84 extends horizontally above both contacts 11 and 12. .. Further, the fourth portion 84 extends to the right side beyond the feeding side contact 12.

As described above, the first conductor 8 is formed so that the width X41 in the horizontal direction is long and the width Y41 in the vertical direction is short. Further, the first conductor 8 is mainly arranged so as to pass above the connection terminal 1.

Here, the loop length L41 of the first conductor 8 will be described. The loop length L31 referred to here includes not only the total length of the first to sixth portions 81 to 86 of the first conductor 8 but also the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the fourth corner 124 of the power feeding side contact 12 and the length from the fourth corner 124 to the first corner 121 of the feeding side contact 12. The sum of the sum and the lengths of the first to sixth parts 81 to 86 is defined as the loop length L41 of the first conductor 8.

Then, the loop length L41 of the first conductor 8 is preferably set by the above-mentioned formula (1) in the same manner as L11 (in the formula (1), L41 is applied instead of L11). Further, a more preferable range is also set in the same manner. This point is the same for the length Y41 in the vertical direction of the first conductor 8, and can be applied to the formula (2).

<5-2. Second conductor>
The second conductor 9 is formed by arranging linear conductors in a loop shape, and both ends thereof are connected to the ground side contact 11 and the power supply side contact 12, respectively. The second conductor 9 is formed by seven portions. That is, from the first portion 91 extending downward from the third corner portion 113 of the ground contact side contact 11, the second portion 92 extending horizontally from the lower end portion of the first portion 91 to the left, and the left end portion of the second portion 92. A third part 93 extending downward, a fourth part 94 extending horizontally from the lower end of the third part 93 to the right, a fifth part 95 extending upward from the right end of the fourth part 94, and a fifth part 95. It is formed by a sixth portion 96 extending horizontally from the upper end portion of the sixth portion 96 and a seventh portion 97 extending upward from the right end portion of the sixth portion 96 and connected to the third corner portion 123 of the power feeding side contact 12. There is.

As shown in FIG. 7, the first portion 91 is common to the first portion 81 of the first conductor 8. Further, the second portion 92 is also common to the second portion 82 of the first conductor 8. Therefore, the third portion 93 extends below the right end portion of the second portion 82 of the first conductor 8. Further, the fifth portion 95 extends in the vertical direction below the ground contact side contact 11, and the upper end portion of the fifth portion 95 is close to the ground side contact 11. The right end of the sixth portion 96 extends below the third corner portion 123 of the power feeding side contact 12.

As described above, the width X42 in the horizontal direction of the second conductor 9 is shorter than that of the first conductor 8, and the width Y42 in the vertical direction is formed to be slightly longer than that of the first conductor 8. Further, the second conductor 9 is arranged so as to pass below the connection terminal 1.

Here, the loop length L42 of the second conductor 9 will be described. The loop length L42 referred to here includes the total length of the first to seventh portions 91 to 97 of the second conductor 9, as well as the distance between the contacts 11 and 12. Specifically, the length from the third corner 113 of the ground contact 11 to the third corner 123 of the power feeding side contact 12 plus the lengths of the first to seventh parts 91 to 97 is added. It is defined as the loop length L42 of the second conductor 9.

Then, the loop length L42 of the second conductor 7 is preferably set by the above-mentioned formula (3) as in the case of L12 (in the formula (3), L42 is applied instead of L12). Further, a more preferable range is also set in the same manner. This point also applies to the vertical length Y42 of the second conductor 9, and can be applied to the equation (4).

<6. Material>
The conductors 2 to 9 as described above are formed by combining wire rods, and these are formed by laminating a conductive material having conductivity on the surface of the window glass 200 so as to have a predetermined pattern. can do. Examples of such a material may have conductivity, and examples thereof include silver, gold, and platinum. Specifically, for example, it can be formed by printing a conductive silver paste containing silver powder, glass frit, etc. on the surface of the window glass 200 and firing it.

<7. Features>
As described above, according to the present embodiment, the following effects can be obtained.
(1) Since each of the glass antennas includes two conductors, that is, loop-shaped first conductors 2, 4, 6, 8 and second conductors 3, 5, 7, 9, it depends on the antenna. The sensitivity of transmission and reception can be improved.

(2) For example, the first conductors 2, 4, 6, and 8 have a length in the horizontal direction longer than that of the first conductor, and thus contribute to improving the sensitivity of transmission and reception. In particular, when the loop lengths L11, L21, L31, and L41 of the first conductors 2, 4, 6, and 8 are set so as to satisfy the equation (1), the reception sensitivity is further improved.

(3) When the lengths of both conductors 2 to 9 in the vertical direction are set so as to satisfy the equations (2) and (4), the sensitivity of transmission and reception of the antenna can be improved.

(4) In each of the glass antennas 101 to 105, the connection terminal 1 is deviated from the center of the glass antennas 101 to 105 in the horizontal direction, which can improve the sensitivity.

(5) As shown in FIG. 1, the glass antennas 101 to 105 can be arranged within 50 mm downward from the upper end of the window glass 200. Thereby, for example, when the mask layer is formed of ceramics or the like on the peripheral edge of the glass plate, the glass antennas 101 to 105 can be arranged on the mask layer, and the glass antennas 101 to 105 can be prevented from being seen from the outside of the vehicle. can do.

(6) The present inventor has no impedance when a conductive member (for example, a connection terminal) is arranged in addition to the coaxial cable in the transmission line between the connection terminal 1 and the transmitter / receiver. It was found that matching occurs and the sensitivity decreases. On the other hand, it has been found that when the second conductor is provided as in the present embodiment, the impedance matching characteristic is improved and the decrease in sensitivity can be suppressed. This point is verified in Example 13 described later. Therefore, for example, the first conductors 2, 4, 6, and 8 affect the improvement of the transmission / reception sensitivity of the antenna, and the second conductors 3, 5, 7, and 9 are expected to improve the impedance matching characteristics. it can. Further, as described above, it is considered that adjusting the shape of the second conductor (for example, satisfying the equation (2)) contributes to the improvement of the impedance matching characteristic.

<8. Modification example>
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. The following modifications can be combined as appropriate.

The shape of the glass antenna can be various, and is not limited to the above embodiment.
(1) The shape of the loop of the first conductor and the second conductor is not particularly limited. However, it is preferable that the width of the first conductor in the horizontal direction is longer than that of the second conductor. Further, it is preferable that the width of the second conductor in the vertical direction is longer than that of the first conductor. The wording "loop-shaped" in the present invention extends so that the conductors connecting the two contacts 11 and 12 are not connected in a straight line but form a space surrounded by the conductors. It means that it is. Since the shape of the space is not particularly limited, each conductor can be composed of a line including at least one of a straight line and a curved line. Further, since both contacts 11 and 12 are separated from each other, the loop shape does not mean a closed line.

(2) A part of the first conductor and the second conductor may be shared as in the first, third and fourth glass antennas 101, 103 and 104.

(3) As in the modified example of the third glass antenna 103 shown in FIG. 6, at least one additional conductor connected to the first conductor and the second conductor may be provided.

(4) The first conductor does not have to be formed in a loop shape. For example, as shown in FIG. 8, the first conductor is formed by the linear antenna elements 81 and 82 extending from the contacts 11 and 12. 80 can be formed. In this case, as shown in FIG. 6, it is preferable that the two antenna elements 81 and 82 extend so as to be separated from each other. The antenna length (corresponding to the loop length) of the first conductor in the example of FIG. 8 is X51. Further, the antenna elements 81 and 82 constituting the first conductor may be formed in a shape other than a straight line, and may be formed in an L shape as shown in FIG. 9, for example. The antenna length of the first conductor in the example of FIG. 9 is X51 + Y51 * 2.

(5) As shown in the glass antenna 107 shown in FIG. 10, an antenna in which the antenna element 81 connected to the ground side contact 11 of the first conductor 810 is formed in a T shape and is connected to the power feeding side contact 12. The element 82 can also be formed in an L shape. The antenna element 81 has a first portion 811 extending upward from the ground contact 11 and a second portion 812 extending horizontally from the upper end of the first portion 811. Here, as shown in FIG. 10, when the first portion 811 is lengthened, a work space for connection such as connection of a connector can be secured between the ground contact side contact 11 and the upper edge 201 of the glass plate 200. it can. On the other hand, the antenna element 82 connected to the feeding side contact 12 has a first portion 821 extending horizontally from the feeding side contact 12 and a second portion 822 extending upward from the end of the first portion 821. Although it is L-shaped, its orientation is different from that of the antenna element 82 shown in FIG.

Like the glass antenna 108 shown in FIG. 11, of the first conductor 810, the antenna element 81 connected to the ground side contact 11 is linearly formed, and the antenna element 82 connected to the power feeding side contact 12 is L. It can also be formed in a character shape. However, the antenna element 82 connected to the power feeding side contact 12 has a first portion 821 extending downward from the feeding side contact 12 and a second portion 822 extending to the left from the lower end portion of the first portion 821. Although it is L-shaped, its orientation is different from that of the antenna element 82 shown in FIGS. 9 and 10. As shown in FIGS. 8 to 11 above, when the first conductors 80 and 810 are composed of two antenna elements, the shape and orientation of each antenna element can be appropriately changed. For example, FIG. ~ Any of the antenna elements 81 and 82 shown in FIG. 11 can be appropriately combined.

(6) Compared to the glass antennas described so far, the glass antenna 109 shown in FIG. 12 is mainly arranged so as to be inclined in the plane direction with respect to the glass plate 200, and the second conductor 3 is the first conductor. The difference is that it is located above the body 800. More specifically, in the glass antenna 109 of FIG. 12, the second conductor 82 extends obliquely with respect to the corner portion 203 where the upper edge 201 and the side edge 202 of the glass plate 200 intersect, and the glass plate 200 It is arranged so as to form a triangular gap near the corner of the. The ground side contact 11 and the power supply side contact 12 are formed in a rectangular loop shape extending diagonally by the first part 31, the second part 32, the third part 33, the fourth part 34, and the fifth part 35. It is connected by a second conductor 3. On the other hand, the first conductor 800 is formed by two antenna elements 81 and 82, and the antenna element 81 connected to the feeding side contact 12 is formed in an L shape. Further, the antenna element 82 connected to the ground contact 11 is formed in a U shape.

More specifically, the antenna element 81 connected to the power feeding side contact 12 has a first portion 811 that extends horizontally to the left from the connecting portion between the first portion 31 and the second portion 32 of the second conductor 3. It has a second portion 812 extending downward from the end of the first portion 811. The second portion 812 extends over the entire vertical direction of the glass antenna 109 and extends parallel to the pillar 500 of the vehicle body arranged along the side edge 202 of the glass plate 200. However, the angle of the second portion 812 can be adjusted with respect to the pillar 500, and for example, the angle α with respect to the pillar 500 can be set to 0 to 45 degrees. By adjusting the angle of the second part 812 in this way, the second part 812 can easily obtain the effect as a reflective member of the pillar 500, whereby the antenna is installed on the arrow X side (passenger seat side). If so, the sensitivity on the driver's side) can be improved. Further, since the glass antenna 109 is arranged near the corner portion 300 of the glass plate 200, it is easy to hide it in a mask layer having a large width particularly near the corner portion 300. Since the antenna element 81 is connected in the middle of the second conductor 3, it can be said that a part of the antenna element 81 is shared with the second conductor 3. This point is the same for the other antenna element 82.

On the other hand, the antenna element 82 connected to the ground contact 11 is parallel to the first portion 821 extending downward from the fifth portion 35 of the second conductor 3 and the pillar 500 from the lower end portion of the first portion 821. It has a second portion 822 extending in parallel to the left side and a third portion 823 extending parallel to the left side from the lower end portion of the second portion 822.

Further, it is preferable that the glass antenna 109 is arranged in a range of about 100 mm in the horizontal direction and about 100 mm in the vertical direction from the corner of the glass plate (see FIG. 23). This point is the same for other glass antennas.

(7) The glass antenna 110 shown in FIG. 13 has a shape similar to the example shown in FIG. 12, but as compared with FIG. 12, the second portion 812 of the antenna element 81 connected to the feeding side contact 12 is It is short, and the third portion 823 of the antenna element 82 connected to the ground contact 11 is long. In particular, the third portion 823 extends over the entire left-right direction of the glass antenna 110 and extends parallel to the roof 600 of the vehicle body arranged along the upper edge 201 of the glass plate 200. However, the angle of the third portion 823 can be adjusted with respect to the roof 600, and for example, the angle β with respect to the roof 600 can be set to 0 to 45 degrees. By adjusting the angle of the third part 823 in this way, the third part 823 can easily obtain the effect as a reflective member of the roof 600, thereby improving the sensitivity on the arrow Y side (front side of the vehicle). Can be made to.

From the examples of FIGS. 12 and 13, the rotational position of the glass plate 200 in the plane direction of the glass antenna is not particularly limited. Further, the second conductor can be arranged above the first conductor. Further, if an antenna element extending in the vertical direction or the horizontal direction of the glass antenna is provided at the end of the first conductor, the effect as a reflecting member of the pillar or the roof can be easily obtained, and the sensitivity is improved. be able to.

(8) The position where the glass antenna is provided is not particularly limited, and the glass antenna can be provided at any position of the window glass 200. Therefore, it can be provided at a position 50 mm away from the upper end of the window glass 200.

Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples.

<A. Examination of the presence or absence of the second conductor>
In the following, the loop length of the glass antenna according to the above embodiment will be examined. In examining the following reception performance, three-dimensional electromagnetic field simulation software was used. In this simulation, a glass plate was modeled assuming a general tempered glass with a thickness of 3.1 mm. Further, the line width of the glass antenna was 1 mm, and the shortening rate α of the glass plate was 0.61 as a model assuming a radio wave having a frequency of 760 MHz. The simulation procedure is as follows: (1) Model the vehicle, dielectric, antenna, etc., set the material, (2) Set the appropriate mesh for the vehicle, dielectric, antenna, etc., and then execute the simulation. did. The setting and execution of such a simulation is common to the examination of all the examples and comparative examples shown below.

なお、表１のループ長は、α＊λ（１波長）に対する割合を示している。 The glass antennas according to Examples 1 and 3 have the shapes shown in FIGS. 2 and 4 as shown below. In the second embodiment, Y21 and Y22 in FIG. 3 have the same length. Further, the length of the third portion of the first conductor was shortened, and the fourth portion was directly connected to the first corner portion of the power feeding side contact. That is, the fifth part was lost. Further, in the fourth embodiment, the upper end of the third portion 93 of the second conductor 9 in FIG. 7 is connected to the vicinity of the center of the second portion 82 of the first conductor 8. The glass antenna shown in FIG. 14 according to the comparative example has only the loop-shaped first conductor 6. Then, the loop length of each glass antenna was set as follows.

The loop length in Table 1 shows the ratio to α * λ (1 wavelength).

The simulation used the moment method. A voltage was applied by connecting the feeding units 11 and 12 with 50Ω, and the radiation pattern of the antenna having an elevation angle of 0 degrees was calculated. In addition, the impedance was calculated to obtain the transmission loss. Since the radiation pattern is calculated every time, 360 data are obtained around the entire vehicle. The value obtained by averaging this data and subtracting the transmission loss was taken as the average sensitivity. The polarization was vertical polarization.

The average sensitivity of the V polarization of the glass antennas according to Examples 1 to 4 and Comparative Example is as shown in Table 2. The average sensitivity dBi here is the sensitivity based on the omnidirectional antenna.

According to Table 2, it can be seen that Examples 1 to 4 having the second conductor have higher sensitivity than Comparative Examples.

<B. Examination of the length (loop length) of the first conductor>
Next, in Example 2, Examples 5 to 8 in which the loop length of the first conductor was adjusted were prepared as shown in Table 3 below, and evaluated by simulation in the same manner. The length in the vertical direction is the same as that of the first conductor of the second embodiment, but the loop length is different. That is, the lengths in the left-right direction are different. The results are shown in Table 4.

As shown in Table 3, the loop lengths of the first conductors of Examples 6 and 7 satisfy the equation (1), and therefore have higher sensitivity than those of Examples 5 and 8. However, even in Examples 5 and 8 which do not satisfy the formula (1), the sensitivity is higher than that of the comparative example.

<C. Examination of vertical lengths of the first conductor and the second conductor>
Next, Examples 9 and 10 in which the vertical lengths of the first conductor and the second conductor were adjusted were produced as shown in Table 5 below. The glass antenna according to the ninth embodiment has the shape shown in FIG. 15, and the glass antenna according to the tenth embodiment has the shape shown in FIG. That is, the glass antennas according to Examples 9 and 10 both have a shape similar to that of Example 2, and the loop lengths of the respective conductors are the same, but the lengths in the vertical direction are different. Specifically, in the glass antennas according to Examples 9 and 10, the lengths of the conductors in the vertical direction are opposite to each other. The results are shown in Table 6.

According to Table 6, when the lengths of the first conductor and the second conductor in the vertical direction are opposite to each other, the sensitivities are substantially the same, but the lengths of the first conductor in the vertical direction are long. 9 was slightly less sensitive. Even as compared with Example 2 in which the lengths of both conductors in the vertical direction are the same, the sensitivity becomes lower as the length of the first conductor in the vertical direction becomes longer.

<D. Examination of the length of the first conductor and the second conductor in the left-right direction>
Next, Example 11 in which the lengths of the first conductor and the second conductor in the left-right direction were adjusted was produced. The glass antenna according to the eleventh embodiment has the shape shown in FIG. 17, and the first conductor and the second conductor in the second embodiment are interchanged, and further turned upside down and connected to each contact. Therefore, the lengths of the first conductor and the second conductor in the left-right direction are opposite to those of the second embodiment. The results are shown in Table 7.

According to Table 7, it was found that the sensitivities changed significantly when the lengths of the first conductor and the second conductor in the left-right direction were opposite to each other as compared with Example 2. That is, it was found that when the length of the second conductor in the left-right direction is longer than the length of the first conductor in the left-right direction, the sensitivity is greatly reduced.

<E. Examination of contact position>
Subsequently, Example 12 in which the positions of both contacts were arranged near the center of the glass antenna was produced. The glass antenna according to the twelfth embodiment has the shape shown in FIG. 18, and in the second embodiment, the left end of the second conductor is extended to substantially the same position as the left end of the first conductor, and both contacts are further extended. It is moving near the center of the glass antenna in the left-right direction. The results are shown in Table 8.

According to Table 8, it was found that when both contacts were moved to the vicinity of the center in the left-right direction of the glass antenna, the sensitivity was significantly reduced as compared with Example 2.

<F. Examination of transmission line>
According to the present inventor, for example, when a conductive member (for example, another connection terminal, an attachment for a connection terminal, etc.) is arranged in addition to the coaxial cable in the transmission line between the connection terminal and the transmitter / receiver. It has been found that the impedance matching characteristics are reduced, resulting in reduced sensitivity. Regarding this, the present inventor has found that the impedance matching characteristic is improved even in such a case by providing the second conductor. The following will be examined.

Three glass antennas were prepared for this study. First, Comparative Example 1 shown in FIG. 14 was prepared, and a case was simulated in which both the power feeding side contact and the grounding side contact were connected to the transmitter / receiver via a coaxial cable having an impedance of 50Ω. As Comparative Example 2, a connection attachment was prepared between both contacts of Comparative Example 1 and a coaxial cable (impedance of 50 Ω). As Example 13, the same glass antenna as in Example 1 was prepared, and a coaxial cable (impedance of 50 Ω) was connected to both contacts via attachments for connection.

FIG. 19 is a graph showing the impedance of each glass antenna. The center of the graph in FIG. 19 shows the impedance of the coaxial cable of 50Ω. In Comparative Example 1 of the transmission line, only the coaxial cable adjusts the impedance according to the coaxial cable, and matches the impedance of the coaxial cable as shown in FIG. On the other hand, in Comparative Example 2 in which an attachment for connection is provided on the transmission line, the impedance is separated from 50Ω due to the influence of the attachment, and the matching characteristic is deteriorated. On the other hand, the thirteenth embodiment having the second conductor eliminates the influence of the attachment and matches the impedance of the coaxial cable.

This point was further examined. FIG. 20 is a calculation of the loss of antenna sensitivity due to the impedance matching characteristics of each glass antenna and the coaxial cable. According to FIG. 20, it can be seen that in Comparative Example 1 and Example 13, the sensitivity loss due to the impedance mismatch is approximately 0 dB. On the other hand, in Comparative Example 2, it can be seen that the sensitivity loss is large due to the influence of the attachment. Therefore, even if an attachment or the like other than the coaxial cable is inserted in the transmission line, the impedance matching characteristic is improved by providing the second conductor as in each embodiment of the present invention including the thirteenth embodiment. As a result, it was found that the decrease in sensitivity was suppressed.

<G. Examination of the shape of the first conductor and the angle of the glass antenna>
21 to 24 are glass antennas according to Examples 14 to 17, respectively. Since these glass antennas are the same as the glass antennas of FIGS. 10 to 13, the description of reference numerals and the like is omitted in FIGS. 21 to 24. Each contact of Example 14 is formed in a square shape of 6 mm × 6 mm, and each contact of Examples 15 to 17 is formed in a rectangular shape of 20 mm × 14 mm. The sensitivities of these Examples 14 to 17 are as follows. Good sensitivity is obtained in each case, and even if the first conductor is not loop-shaped and is composed of two antenna elements, it shows good sensitivity. Further, even if the glass antennas are arranged diagonally as in Examples 16 and 17, the sensitivity is not affected.

Next, Example 15 was further examined. That is, of the first conductor, Example 18 in which the antenna element connected to the ground contact 11 is not provided was produced. Then, for Examples 15 and 18, the sensitivities in three directions were calculated. The results are as follows. As shown in Table 10, it was found that Example 18 having no antenna element connected to the ground contact 11 was inferior in sensitivity to Example 15 in all three directions.

1 Connection terminal 11 Ground side contact 12 Power supply side contact 2, 4, 6, 8 First conductor 3, 5, 7, 9 Second conductor 101-104 Glass antenna 200 Window glass

Claims (13)

A glass antenna installed on the window glass of a vehicle that transmits and receives ITS radio waves.
A connection terminal having a power supply side contact and a ground side contact,
The first conductor connected to the power feeding side contact and the grounding side contact,
A loop-shaped second conductor connecting the power feeding side contact and the grounding side contact,
It has a glass antenna. A glass antenna installed on the window glass of a vehicle that transmits and receives ITS radio waves.
A connection terminal having a power supply side contact and a ground side contact,
The first conductor connected to the power feeding side contact and the grounding side contact,
A loop-shaped second conductor that connects the power feeding side contact and the grounding side contact and shares a part of the first conductor.
It has a glass antenna. The glass antenna according to claim 1 or 2, wherein the first conductor is formed in a loop shape connecting the power feeding side contact and the grounding side contact. The first conductor is configured to adjust the sensitivity of transmitting and receiving the radio waves.
The glass antenna according to any one of claims 1 to 3, wherein the second conductor is configured to adjust impedance matching characteristics. The glass antenna according to claim 3 or 4, wherein the horizontal width of the first conductor is longer than the horizontal width of the second conductor. The glass antenna according to any one of claims 3 to 5, wherein the vertical width of the first conductor is shorter than the vertical width of the second conductor. Claimed that the vertical length of the first conductor and the vertical length of the second conductor are both 0.01 to 0.2 times the wavelength of the radio wave. Item 4. The glass antenna according to any one of Items 3 to 6. The method according to any one of claims 1 to 7, wherein the total length of the second conductor and the distance between the two contacts is a length corresponding to 0.5 to 0.9 times the wavelength of the radio wave. Glass antenna. The method according to any one of claims 1 to 8, wherein the total length of the first conductor and the distance between the two contacts is a length corresponding to 0.9 to 1.3 times the wavelength of the radio wave. Glass antenna. The glass antenna according to any one of claims 1 to 9, which is arranged in a range of 50 mm downward from the upper edge of the window glass. The glass antenna according to any one of claims 1 to 10, wherein the connection terminal is arranged at a position shifted in the horizontal direction from the horizontal center of the first conductor and the second conductor. At least a part of the first conductor is arranged above the connection terminal.
The glass antenna according to any one of claims 1 to 11, wherein at least a part of the second conductor is arranged below the connection terminal. The glass antenna according to any one of claims 1 to 12, wherein the impedance of the transmission line connected to the connection terminal is 40 to 80 Ω.

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