On-vehicle radar device and vehicle
An on-vehicle radar device includes a mount and an antenna configured to transmit a transmission wave from an inner side of laminated glass, which includes an innermost glass layer, an outermost glass layer, and an intermediate resin layer, and receive a reflected wave. The antenna includes a transmitting antenna. When the mount is mounted on a bracket, the incident angle of the transmission wave on the innermost glass layer is greater than a Brewster angle on the inner surface of the innermost glass layer, and the incident angle of the transmission wave on the outermost glass layer is less than or equal to a Brewster angle between the outermost glass layer and the intermediate resin layer.
1. An on-vehicle radar device comprising:
a mount configured to be mounted on a bracket that is fixed to one of an innermost glass layer of laminated glass, a rear-view mirror placed on an inner side of the innermost glass layer, and a ceiling, the laminated glass including the innermost glass layer, an outermost glass layer, and an intermediate resin layer that is sandwiched between the innermost glass layer and the outermost glass layer; and
an antenna configured to transmit a transmission wave from the inner side of the innermost glass layer to an outer side of the outermost glass layer and to receive a reflected wave that enters from the outer side of the outermost glass layer to the inner side of the innermost glass layer, the transmission wave being a radio wave in a millimeter wave band;
wherein
the antenna includes a transmitting antenna configured to transmit the transmission wave;
a vertical polarization component of the transmission wave relative to the laminated glass is greater than a horizontal polarization component thereof;
when the mount is mounted on the bracket, an incident angle of the transmission wave on the innermost glass layer at a center of a main lobe of the transmitting antenna is greater than a Brewster angle on an inner surface of the innermost glass layer, and an incident angle of the transmission wave on the outermost glass layer at the center of the main lobe is less than or equal to a Brewster angle between the outermost glass layer and the intermediate resin layer; and
a difference between the Brewster angle and the incident angle of the transmission wave on the innermost glass layer at the center of the main lobe of the transmitting antenna is less than or equal to about 25% of a difference between 90 degrees and the Brewster angle.
2. The on-vehicle radar device according to claim 1 , wherein
the antenna includes another transmitting antenna configured to transmit another transmission wave that has a different radiation pattern from a radiation pattern of the transmission wave; and
when the mount is mounted on the bracket, an incident angle of the another transmission wave on the innermost glass layer at a center of a main lobe of the another transmitting antenna is greater than the Brewster angle on the inner surface of the innermost glass layer, and an incident angle of the another transmission wave on the outermost glass layer at the center of the main lobe is less than or equal to the Brewster angle between the outermost glass layer and the intermediate resin layer.
3. The on-vehicle radar device according to claim 1 , wherein the intermediate resin layer is made of polyvinyl butyral.
4. The on-vehicle radar device according to claim 2 , wherein the intermediate resin layer is made of polyvinyl butyral.
5. The on-vehicle radar device according to claim 1 , wherein the antenna includes at least one of a horn antenna, a lens antenna, a printed antenna, a microstrip antenna, and a slit antenna.
6. The on-vehicle radar device according to claim 1 , wherein the antenna is a horn antenna.
7. The on-vehicle radar device according to claim 1 , further comprising:
a camera configured to observe an outside from an inner side of the laminated glass; and
a cover that is configured to cover the antenna and the camera.
8. The on-vehicle radar device according to claim 2 , further comprising:
a camera configured to observe an outside from an inner side of the laminated glass; and
a cover that is configured to cover the antenna and the camera.
9. The on-vehicle radar device according to claim 3 , further comprising:
a camera configured to observe an outside from an inner side of the laminated glass; and
a cover that is configured to cover the antenna and the camera.
10. The on-vehicle radar device according to claim 4 , further comprising:
a camera configured to observe an outside from an inner side of the laminated glass; and
a cover that is configured to cover the antenna and the camera.
11. A vehicle comprising:
a vehicle body;
a drive mechanism configured to move the vehicle body;
laminated glass that is fixed to the vehicle body and located between a vehicle interior and a vehicle exterior; and
an on-vehicle radar device that is fixed directly or indirectly to one of an inner surface of the laminated glass, a rear-view mirror that is placed on an inner side of the inner surface, and a ceiling; wherein
the laminated glass includes an innermost glass layer, an outermost glass layer, and an intermediate resin layer that is sandwiched between the innermost glass layer and the outermost glass layer;
the on-vehicle radar device includes an antenna configured to transmit a transmission wave from an inner side of the innermost glass layer to an outer side of the outermost glass layer and receive a reflected wave that enters from the outer side of the outermost glass layer to the inner side of the innermost glass layer, the transmission wave being a radio wave in a millimeter wave band;
the antenna includes a transmitting antenna configured to transmit the transmission wave;
a vertical polarization component of the transmission wave relative to the laminated glass is greater than a horizontal polarization component thereof;
an incident angle of the transmission wave on the innermost glass layer at a center of a main lobe of the transmitting antenna is greater than a Brewster angle on an inner surface of the innermost glass layer, and an incident angle of the transmission wave on the outermost glass layer at the center of the main lobe is less than or equal to a Brewster angle between the outermost glass layer and the intermediate resin layer; and
a difference between the Brewster angle and the incident angle of the transmission wave on the innermost glass layer at the center of the main love of the transmitting antenna is less than or equal to about 25% of a difference between 90 degrees and the Brewster angle.
12. The vehicle according to claim 11 , wherein
the antenna includes another transmitting antenna configured to transmit another transmission wave that has a different radiation pattern from a radiation pattern of the transmission wave;
an incident angle of the another transmission wave on the innermost glass layer at a center of a main lobe of the another transmitting antenna is greater than the Brewster angle on the inner surface of the innermost glass layer, and an incident angle of the another transmission wave on the outermost glass layer at the center of the main lobe is less than or equal to the Brewster angle between the outermost glass layer and the intermediate resin layer; and
the intermediate resin layer is made of polyvinyl butyral.