Patent Grant
11563263
The present invention relates to a glass antenna for receiving a circularly polarized wave in a frequency range from 1 GHz to 2 GHz.
In vehicles such as automobiles, satellite positioning systems typified by GPS have been used. The satellite positioning system requires an antenna capable of receiving, from GPS satellites, circularly polarized waves in the L1 (1.575 GHz) frequency band. As an example of the antenna for receiving such circularly polarized waves, there is known a glass antenna which has a rectangular shape as a whole and includes a loop-shaped antenna element, a parasitic element and a conductor arranged surrounding these elements as disclosed in Patent Document 1.
Furthermore, the use of multiple satellite positioning systems, that is, the use of circularly polarized waves in multiple frequency bands have recently been proposed to implement a higher-precision positioning system. For example, Patent Document 2 discloses a system unit which has an antenna adapted to a first positioning mode using a GPS satellite and an antenna adapted to a second positioning mode using a GLONASS satellite.
Patent Document 1: Japanese Laid-Open Patent Publication No. 2009-118268
Patent Document 2: Japanese Laid-Open Patent Publication No. 2016-205881
In the case where a satellite positioning system unit using circularly polarized waves in multiple frequency bands is implemented in a vehicle, it is not practical to provide antennas adapted to the respective frequency bands because of the limited installation space for the antennas in the vehicle. In order to implement such a satellite positioning system unit in the vehicle, it is useful to provide a glass antenna capable of receiving multiple circularly polarized waves in a frequency range from 1 GHz to 2 GHz.
In view of the foregoing, it is an object of the present invention to provide a glass antenna with an improved circularly polarized wave reception bandwidth so as to receive circularly polarized waves in multiple arbitrary frequency bands within a frequency range of 1 GHz to 2 GHz.
According to one aspect of the present invention, there is provided a glass antenna for receiving a circularly polarized wave in an arbitrary frequency band within a frequency range from 1 GHz to 2 GHz, the glass antenna being configured for mounting to a window glass of a vehicle and comprising a metal body part of the vehicle as an antenna element, the glass antenna comprising:
a core-side feeding part;
a ground-side feeding part arranged adjacent to the core-side feeding part;
a first element extending from the ground-side feeding part; and
a parasitic element including a first wire, a second wire arranged parallel to or substantially parallel to the first wire and a third wire connecting the first wire and the second wire to each other,
wherein the parasitic element is disposed to surround the core-side and ground-side feeding parts at a position between an edge of the metal body part located adjacent to the core-side and ground-side feeding parts and the third wire,
wherein the core-side feeding part is disposed in an area surrounded by the first wire, the third wire, the first element, the ground-side feeding part and the edge of the metal body part,
wherein a blank portion is provided between the parasitic element and the first element such that the parasitic element and the first element allows resonance with a radio wave in any arbitrary frequency band within the frequency range, and
wherein, when the window glass is mounted to the vehicle,
This glass antenna attains at least three routes for reception of circularly polarized waves.
The first route is as follows: the ground-side feeding part→the first element→the blank portion between the first element and the parasitic element→the parasitic element→the blank portion between the first end of the parasitic element and the metal body part→the metal body part→the blank portion between the metal body part and the ground-side feeding part→the ground-side feeding part.
The second route is as follows: the ground-side feeding part→the first element→the blank portion between the first element and the parasitic element→the parasitic element→the second end of the parasitic element→the metal body part→the blank portion between the metal body part and the ground-side feeding part→the ground-side feeding part.
The third route is as follows: the ground-side feeding part→the blank portion between the metal body part and the ground-side feeding part→the metal body part→the second end of the parasitic element→the parasitic element→the blank portion between the first end of the parasitic element and the metal body part→the metal body part→the blank portion between the metal body part and the ground-side feeding part→the ground-side feeding part.
In the first to third routes, the first end and the metal body part are disposed via the blank portion; and the second end and the metal body part are disposed via the blank portion or are connected directly.
Each of these routes allows flow of electric signals in a forward direction or reverse direction of the arrows (→). Wirings are connected to the ground-side feeding part and the core-side feeding part through a connector etc. The core-side wiring for connection to any equipment for an amplifier, a navigation system etc. is connected to the core-side feeding part. Within the connector, the electric signal is coupled to the core-side element in a high-frequency manner or is coupled from the ground-side feeding part to the core-side feeding part in a high-frequency manner. The electric signal is hence transmitted to the equipment.
The third route is adaptable to lower frequencies than the first and second routes so as to execute radio wave reception in a lower frequency band within the frequency range of 1 to 2 GHz. The first and second routes are adaptable to higher frequencies than the third route so as to execute radio wave reception in a higher frequency band within the frequency range of 1 to 2 GHz.
In each route, the blank portion sets some spacing that allows resonance with a desired radio wave in the frequency range of 1 to 2 GHz. With such spacing, the design for reception of circularly polarized waves in multiple arbitrary frequency bands is made easy. The glass antenna thus achieves a high reception sensitivity for circularly polarized waves in multiple arbitrary frequency bands.
It is considered from the above reasons that the glass antenna according to one aspect of the present invention efficiently receives circularly polarized waves in multiple frequency bands.
In view of this, it is preferable that both of the first and second ends are in a positional relationship with the metal body part so as to allow resonance with a radio wave in any arbitrary frequency band within the frequency range, that is, the blank portions are respectively provided between the first end and the metal body part and between the second end and the metal body part in the in-plane direction of the vehicle window glass.
According to another aspect of the present invention, there is provided a window glass structure for a vehicle, comprising: the above-mentioned glass antenna.
More specifically, the vehicle window glass structure is provided with the vehicle window glass, the metal body part and the glass antenna. The glass structure is formed in which a peripheral edge portion of the window glass is bonded to the metal body part by an adhesive.
The glass antenna according to the present invention has an improved bandwidth for reception of circularly polarized waves in the frequency range from 1 GHz to 2 GHz, and thus can suitably be applied to a vehicular positioning system unit using multiple satellite positioning systems. In particular, the glass antenna according to the present invention can suitably be applied to a vehicular positioning system unit using multiple satellite positioning systems associated with GPS satellites in the L1 frequency band because the glass antenna easily receives circularly polarized waves in the 1.575 GHz frequency band with good sensitivity.
A glass antenna 1 according to one embodiment of the present invention will be described in detail below with reference to the drawings.
The glass antenna 1 is configured to receive circularly polarized waves in a frequency range of 1 to 2 GHz by being mounted to the vehicle window glass 2. The glass antenna 1 has the metal body part 7 as an antenna element, and also has a core-side feeding part 3, a ground-side feeding part 4 arranged adjacent to the core-side feeding part 3, a first element 5 extending from the ground-side feeding part 4 and a parasitic element 6 including a first wire 61, a second wire 62 extending parallel to or substantially parallel to the first wire 61 and a third wire 63 connecting the first wire 61 and the second wire 62 to each other. The parasitic element 6 is disposed to surround the core-side and ground-side feeding parts 3 and 4 at a position between the edge of the metal body part 7 located adjacent to the core-side and ground-side feeding parts 3 and 4 and the third wire 63. The core-side feeding part 3 is disposed in an area surrounded by the first wire, the third wire, the first element, the earth-side feeding part and the edge 71 of the metal body part. In
As to the relationship of the core-side feeding part 3 and the ground-side feeding part 4, the wording “adjacent” means that there is a distance at which core-side and ground-side terminals of a connector can be respectively connected to the corresponding feeding parts 3 and 4 or there is a distance at which an electric signal passing through the glass antenna 1 can be coupled from one feeding part to the other feeding part in a high-frequency manner. In the case where each of the core-side feeding part 3 and the ground-side feeding part 4 has an area of 15 to 100 mm2, for example, the spacing between these feeding parts may be 3 mm to 10 mm. Further, the arrangement direction of the core-side feeding part 3 and the ground-side feeding part 4 may be parallel to or substantially parallel to the edge 71.
A blank portion 94 is provided between the first element 5 and the parasitic element 6 such that the first element 5 and the parasitic element 6 are in a positional relationship that allows resonance with any arbitrary radio wave in the above-mentioned frequency range. For high-frequency coupling, it is preferable that the blank portion 94 is defined by a free end 511 of the first element 5 and the parasitic element 6. A length of the blank portion 94 can be adjusted within the range of 1 mm to λ(1)×0.5×α (where λ(1) is an arbitrary wavelength in a free space within the above-mentioned frequency range; and α is a wavelength shortening coefficient of glass and is taken as 0.7) so as to allow resonance with any radio wave in the above-mentioned frequency range.
Herein, the definition of a blank portion in the glass antenna according to the present embodiment will be explained below with reference to
It is preferable that the first element 5 is arranged extending toward the third wire 63. In such an arrangement, it becomes easy to distinguish the difference between the distance of the first/second route and the distance of the third route. This contributes to an improvement in the bandwidth for reception of circularly polarized waves in the frequency range of 1 GHz to 2 GHz.
In a state that the window glass 2 is mounted to the vehicle, the core-side feeding part 3 and the ground-side feeding part 4 are disposed between the edge 71 of the metal body part 7 located adjacent to these feeding parts and the third wire 63. A blank portion 93 is provided between the metal body part 7 and the ground-side feeding part 4 such that the ground-side feeding part 4 and the metal body part 7 are in a positional relationship that allows resonance with any arbitrary radio wave in the above-mentioned frequency range. A length of the blank portion 93 can be adjusted within the range of e.g. 5 mm to λ(1)×0.5 so as to allow resonance with any radio wave in the above-mentioned frequency range. In terms of improvement in the reception sensitivity for circularly polarized waves, it is preferable that the third wire 63 is arranged parallel to or substantially parallel to the edge 71 of the metal body part 7 located adjacent to the core-side and ground-side feeding parts 3 and 4.
A distance and sizes of the ground-side feeding part 4 and the core-side feeding part 3 are set according to the shape of the corrector connected to these feeding parts. The distance of the feeding parts may be set to 5 mm to 30 mm. The size of the feeding part may be set to 25 mm2 to 360 mm2. The distance between the core-side feeding part 3 and the edge 71 of the metal body part 7 located adjacent to the core-side feeding part 3 can be the same as the length of the blank portion 93.
In the present embodiment of
Preferably, the glass antenna 1 has a second element 8 extending from the core-side feeding part 3. The second element 8 is in a positional relationship with the parasitic element and the metal body part so as not to allow resonance with a radio wave in the above-mentioned frequency range. For example, the second element 8 can be of linear shape, L-shape or the like. The arrangement of such a second element 8 enables fine adjustment of the reception band. A length of the second element 8 can be adjusted within the range of 5 mm to 50 mm.
In the parasitic element 6, it is preferable that: a minimum distance (III) between a first connection point 612 at which the first wire 61 and the third wire 63 are connected to each other and a second connection point 622 at which the second wire 62 and the third wire 63 are connected to each other is in the range of ±25% of (0.5×λ(2)×α)×A; and a minimum distance (I) between the first connection point 612 and the edge 71 of the metal body part 7 and a minimum distance (II) between the second connection point 622 and the edge 71 of the metal body part 7 are each in the range of (0.25×λ(2)×α) to (0.5×λ(1)×α) (where λ(2) is an arbitrary wavelength in a free space within the above-mentioned frequency range and satisfies a relationship of λ(1)>λ(2); and A is an integer of 1 to 3). When the lengths of the respective element parts of the parasitic element 6 and the positional relationship between the parasitic element 6 and the edge 71 of the metal body part 7 are adjusted to satisfy the above ranges, it is possible to easily improve the appearance shape of the glass antenna 1 and the bandwidth for reception of circularly polarized waves in the frequency range of 1 GHz to 2 GHz.
Further, it is preferable that the minimum distance (III) between the first connection point 612 and the second connection point 622, the minimum distance (I) between the first connection point 612 and the edge 71 of the metal body part 7 and the minimum distance (II) between the second connection point 622 and the edge 71 of the metal body part 7 are in a relationship of (I)+(II)>(III). By satisfaction of such a relationship, the lengths of long and short axes of the electromagnetic field generated in the glass antenna 1 are made closer to each other so that it is possible to easily improve the reception sensitivity for circularly polarized wave.
Furthermore, it is preferable that the parasitic element 6 includes at least one bent-shaped detour wire 64 arranged in an area surrounded by the first wire 61, the second wire 62 and the third wire 63 as shown as a derivative example of the parasitic element in
In the case where the parasitic element 6 has a detour wire 64, it is preferable in terms of appearance improvement that the detour wire 64 is formed to make a detour in a direction perpendicular to a line from which any of the first wire 61, the second wire 62 and the third wire 63 starts and on a side where the feeding parts 3 and 4 are surrounded by the parasitic element 6.
It is also preferable that: starting and end points 951 and 952 of the detour wire (provided that the starting point is an end of the detour wire closer to the connection point 612, 622) are disposed on a route of the minimum distance (III) between the first connection point and the second connection point, the minimum distance (I′) between the first connection point and the first end and the minimum distance (II′) between the second connection point and the second end; and the starting and end points 951 and 952 of the detour wire 64 are in a positional relationship that allows resonance with any radio wave in the above-mentioned frequency range. A length of the spacing between these starting and end points along the minimum distance route can be adjusted within the range of 1 mm to λ(1)×0.5×α. When the parasitic element 6 has such a configuration, it is possible to widen the width of the reception band. In terms of appearance, the connection point 612, 622 and the starting point 951 are preferably located close to each other. For example, the distance between the connection point and the starting point may be adjusted within the range of 3 mm to 20 mm.
The respective elements and feeding parts can be formed on a surface of the vehicle window glass 2 by using a conductive ceramic paste or the like. The ceramic paste is patterned onto the surface of the window glass by screen printing etc. and fired by a heating furnace or the like so that the ceramic pattern is fixed as the pattern of the glass antenna. Alternatively, a light-transparent resin film on which the antenna elements are formed may be adhered to the glass surface. Among the elements of the glass antenna, the width of the linear element may be adjusted to about 0.5 mm to 1 mm.
Any or each of the elements of the glass antenna may be formed on a black frame of a peripheral edge portion of the vehicle window glass 2.
A curved, trapezoidal or rectangular glass plate is used as the vehicle window glass 2. The glass plate can be of either single plate glass or laminated glass. Further, the glass plate can be of either strengthened glass or non-strengthened glass. As the window glass 2, usable is a glass plate formed of soda-lime silicate glass by a float method according to ISO 16293-1 and generally used as a glass plate for a vehicle. The glass plate may be colorless or colored
A glass antenna 1 shown in
<Core-Side Elements>
Size of core-side feeding part 3: 12 mm×10 mm
Second element 8: linear shape of 5 mm in length
<Ground-Side Elements>
Size of ground-side feeding part 4: 12 mm×10 mm
The core-side feeding part 3 and the ground-side feeding part 4 were arranged to maintain a parallel positional relationship with the edge 71 of the metal body part 7.
Length of blank portion 93: 10 mm
First Element 5:
The first element was arranged to extend at an angle of 45 degrees with respect to the third wire 63 of the parasitic element 6; and the length of the first element was set to 27 mm.
Length of blank portion 94: 4 mm
<Parasitic Element>
First wire 61: linear shape of 25 mm in length
Second wire 62: linear shape of 25 mm in length
Third wire 63: linear shape of 80 mm in length
The first wire 61 and the second wire 62 were arranged parallel to each other; and the third wire 63 was arranged parallel to the edge 71 of the metal body part 7. The parasitic element was thus formed in a U-shape where the core-side feeding part 3 and the ground-side feeding part 4 were surrounded by the first, second and third wires. The minimum distance between the first connection point 611 and the second connection point 622 was set to 80 mm.
Length of blank portion 91: 20 mm
The minimum distance between the first connection point 611 and the edge 71 of the metal body part 7 was set to 45 mm.
Length of blank portion 92: 20 mm
The minimum distance between the second connection point 622 and the edge 71 of the metal body part 7 was set to 45 mm.
A glass antenna having the same pattern structure as that of Example 1 was prepared, except that: the length of the second wire 62 was set to 45 mm; and the blank portion 92 was not provided.
A glass antenna having the same pattern structure as that of Example was prepared, except that: the parasitic element 6 was configured in the form of the derivative example shown in
A glass antenna having the same pattern structure as that of Example 1 was prepared, except that: the length of the first element 5 was set to 33 mm; and the blank portion 94 was no provided.
A glass antenna having the same pattern structure as that of Example 1 was prepared, except that: the length of the first wire 61 was set to 45 mm; and the blank portion 91 was not provided.
A glass antenna having the same pattern structure as that of Example 1 was prepared, except that: the length of the first wire 61 and the length of the second wire 62 were both set to 45 mm; and the blank portions 91 and 92 were not provided.
The axial ratios of polarized waves received in the range of 1 GHz to 2 GHz in the respective Examples and Comparative Examples are shown in
It has thus been shown that the glass antenna according to the above-mentioned embodiment of the present invention has an improved bandwidth for reception of circularly polarized waves in the frequency range from 1 GHz to 2 GHz.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2018-100104 | May 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/018480 | 5/9/2019 | WO |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2019/225321 | 11/28/2019 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20070080876 | Kagaya et al. | Apr 2007 | A1 |
| 20100231468 | Ogino | Sep 2010 | A1 |
| 20160306050 | Shingyoji | Oct 2016 | A1 |
| 20190312341 | Tonoe et al. | Oct 2019 | A1 |
| 20190319334 | Dai | Oct 2019 | A1 |
| Number | Date | Country |
|---|---|---|
| 3 611 795 | Feb 2019 | EP |
| 2007-124630 | May 2007 | JP |
| 2009-118268 | May 2009 | JP |
| 2011-151624 | Aug 2011 | JP |
| 2013-198090 | Sep 2013 | JP |
| 2016-205881 | Dec 2016 | JP |
| 10-2011-0105724 | Sep 2011 | KR |
| WO-02056412 | Jul 2002 | WO |
| Entry |
|---|
| Takeyasu et al. (JP 2013/198090), machine translation. (Year: 2013). |
| Supplementary European Search Report issued in European Application No. 19806458.6 dated Jun. 25, 2021 (fourteen (14) pages). |
| International Search Report (PCT/ISA/210) issued in PCT Application No. PCT/JP2019/018480 dated Jun. 18, 2019 with English translation (two (2) pages). |
| Japanese-language Written Opinion (PCT/ISA/237) issued in PCT Application No. PCT/JP2019/018480 dated Jun. 18, 2019 (three (3) pages). |
| Number | Date | Country | |
|---|---|---|---|
| 20210203055 A1 | Jul 2021 | US |
