ANTENNA DEVICE

1 . An antenna device mounted on a vehicle configured to communicate between the vehicle and another vehicle, between a road and the vehicle, or between a pedestrian and the vehicle via at least one antenna, the antenna device comprising:

a memory; and

a processor coupled to the memory and configured to:

detect at least one of a traveling place, a traveling state, and a communication history of the vehicle; and

set a transmission range of a radio wave transmitted from the antenna based on a detection result.

2 . The antenna device according to claim 1 , wherein

the processor is configured to:

detect a road type of the road on which the vehicle is traveling; and

set the transmission range of the radio wave transmitted from the antenna to a range according to the road type.

3 . The antenna device according to claim 1 , wherein

the processor is configured to:

detect a road line shape or a road incidental item of the road on which the vehicle is traveling; and

set the transmission range of the radio wave transmitted from the antenna to a range according to the road line shape or the road incidental item.

4 . The antenna device according to claim 1 , wherein

the processor is configured to:

detect a vehicle speed of the vehicle; and

set the transmission range of the radio wave transmitted from the antenna to be narrower when the vehicle speed is equal to or higher than a threshold value than when the vehicle speed is less than the threshold value.

5 . The antenna device according to claim 1 , wherein

the processor is configured to:

detect an inclination of the vehicle in a front-rear direction that does not depend on a road shape; and

set the transmission range of the radio wave transmitted from the antenna to form a predetermined angle with respect to a road surface of the road when the inclination is equal to or larger than a predetermined value.

6 . The antenna device according to claim 1 , wherein

the processor is configured to:

detect a communication history of the vehicle; and

set the transmission range of the radio wave transmitted from the antenna based on a transmission range of a radio wave when the vehicle has performed communication around a same position in past.

7 . The antenna device according to claim 1 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.

8 . The antenna device according to claim 2 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.

9 . The antenna device according to claim 3 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.

10 . The antenna device according to claim 4 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.

11 . The antenna device according to claim 5 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.

12 . The antenna device according to claim 6 , wherein

the processor is configured to:

further detect whether communication has been established with an outside of the vehicle; and

direct, in response to detecting that the communication has been established, a transmission direction of the radio wave transmitted from the antenna to a direction in which the communication has been established.