Vehicle antenna device
A vehicle antenna includes: a vehicle window glass an electronic device provided in a vicinity of a vehicle width direction central portion at or near upper portion of the vehicle window glass; and an antenna attached to the upper portion of the vehicle window glass such that a normal to a radiation surface passes through a principal surface. A vehicle width direction central position of the antenna is separated from a reference position that is a vehicle width direction center of the electronic device.
1 . A vehicle antenna device comprising:
a vehicle window glass attachable to a vehicle so as to configure at least one of a windshield or a rear glass;
an electronic device provided at a vehicle width direction central portion at or near a vehicle up-down direction upper portion of the vehicle window glass when the vehicle window glass has been attached to the vehicle; and
an antenna that is provided with a radiation conductor including a radiation surface for transmitting and receiving radio waves of a prescribed frequency band, the radiation conductor being attached to the upper portion of a principal surface at an interior side of the vehicle window glass such that a normal to the radiation surface passes through the principal surface, wherein:
a vehicle width direction central position of the antenna is separated, by a prescribed distance in the vehicle width direction, from a reference position that is at a vehicle width direction center of the electronic device provided at the central portion at or near the upper portion of the vehicle window glass,
when the vehicle window glass attached to the vehicle is viewed along the vehicle up-down direction, the radiation surface is in a state inclined with respect to the vehicle width direction and a vehicle front-rear direction such that a second end portion of the radiation surface, which is an end portion on an opposite side from a reference position side of the radiation surface, is positioned further toward a lower edge side of the vehicle window glass than a first end portion, which is an end portion on the reference position side of the radiation surface,
a vehicle width direction position of a portion of the electronic device is aligned with a center line passing in the vehicle front-rear direction through a vehicle width direction center of the vehicle; and
(
WA
/
2
)
×
0.2
≤
W
P
≤
(
WA
/
2
)
×
0.8
is
satisfied
,
wherein WA (mm) is a vehicle width of the vehicle at the vehicle width direction central position of the antenna, and WP (mm) is a distance in the vehicle width direction from the center line to the vehicle width direction central position of the antenna; and
the expression
0.5
≤
θ
H
/
{
(
WP
/
(
WA
/
2
)
)
×
100
}
≤
2.
is satisfied, wherein θH(°) is an angle formed between the antenna and the vehicle width direction.
2 . The vehicle antenna device of claim 1 , wherein the electronic device is attached to the principal surface at the interior side of the vehicle.
3 . The vehicle antenna device of claim 1 , wherein the angle θH(°) is from 15° to 60°.
4 . The vehicle antenna device of claim 1 , wherein the distance WP (mm) is from 100 mm to 500 mm.
5 . The vehicle antenna device of claim 1 , wherein a shortest distance between the antenna and a metal body of the vehicle is not less than 20 mm.
6 . The vehicle antenna device of claim 1 , wherein a shortest distance between a portion of the electronic device where radio waves are emitted and a portion of the antenna where radio waves are emitted is not less than 50 mm.
7 . The vehicle antenna device of claim 1 , wherein the antenna is provided at the vehicle window glass such that an angle formed between the radiation surface of the antenna and the vehicle up-down direction does not fall outside ±15° when the vehicle is viewed along a width direction of the antenna.
8 . The vehicle antenna device of claim 1 , wherein there is only a single antenna provided at a single vehicle window glass, and the antenna includes only a single radiation conductor connected to a single feeding portion through a connecting conductor.
9 . The vehicle antenna device of claim 1 , wherein the antenna is a patch antenna.
10 . The vehicle antenna device of claim 1 , wherein the antenna is capable of transmitting and receiving radio waves in a 5.8 GHz band or radio waves in a 5.9 GHz band.
11 . The vehicle antenna device of claim 1 , wherein the vehicle window glass includes the windshield and the rear glass.