Antenna device
An antenna device that has a housing formed with a window surface and transmits and receives an electromagnetic wave through a cover member facing the window surface, the antenna device having a length in a direction of transmitting and receiving the electromagnetic wave that is greater than a height thereof, comprises: a circuit board that is provided inside the housing; a reflection plate that is provided inside the housing and faces a board surface of the circuit board; a transmitting antenna that is provided inside the housing and transmits the electromagnetic wave to a side of the reflection plate; and a receiving antenna that is provided inside the housing and receives the electromagnetic wave.
1. An antenna device that includes a housing formed with a window surface and configured to transmit and receive an electromagnetic wave through a cover member facing the window surface, the antenna device having a length in a direction of transmitting and receiving the electromagnetic wave that is greater than a height thereof, comprising:
a circuit board that is provided inside the housing;
a reflector that is provided inside the housing and faces a board surface of the circuit board;
a transmitting antenna that is provided on the board surface and transmits the electromagnetic wave to a side of the reflector; and
a receiving antenna that is provided on the board surface and receives the electromagnetic wave,
wherein a reflection surface of the reflector has convex shape warping in an outside direction extending from right and left sides relative to a position where the transmitting antenna and the receiving antenna are disposed, and
wherein the transmitting antenna and the receiving antenna respectively have a plurality of antenna elements disposed between the right and left sides where the reflector extends.
2. The antenna device according to claim 1 , further comprising:
a radome that covers a direction in which the electromagnetic wave is transmitted and received.
3. The antenna device according to claim 1 , further comprising:
a dielectric lens that is supported forward of the circuit board, narrows a beam of the electromagnetic wave from the reflector to emit the beam outside the antenna device, and collects the electromagnetic wave from outside the antenna device into the reflector.
4. The antenna device according to claim 3 , wherein
the dielectric lens converts the electromagnetic wave transmitted from the transmitting antenna to a plane wave.
5. The antenna device according to claim 4 , wherein
the dielectric lens is composed of a convex lens that has a convex shape in a front surface side.
6. The antenna device according to claim 1 , wherein
the transmitting antenna and the receiving antenna are each composed of a conductor pattern formed on the board surface of the circuit board.
7. The antenna device according to claim 6 , wherein
the transmitting antenna and the receiving antenna are patch antennae.
8. The antenna device according to claim 1 , wherein
the reflector reflects a beam of the electromagnetic wave transmitted from the transmitting antenna so as to narrow a beam width and reflects the electromagnetic wave from a front side such that the electromagnetic wave is collected.
9. The antenna device according to claim 8 , wherein
in at least a vertical direction, the reflection surface of the reflector has a parabolic surface shape having a focal point at which the transmitting antenna and the receiving antenna are disposed.
10. The antenna device according to claim 1 , further comprising:
the housing having a window on a front surface through which the electromagnetic wave passes and stores the circuit board so as to transmit and receive the electromagnetic wave through the window.
11. The antenna device according to claim 10 , wherein
the housing includes a metal.
12. The antenna device according to claim 10 , wherein
when a normal direction of the board surface of the circuit board is regarded as a vertical direction, a length in the vertical direction of the housing is shorter than a length in a front-rear direction of the housing.
13. The antenna device according to claim 10 , wherein
the housing has a connector that thermally bonds with the circuit board or a circuit part mounted on the circuit board.
14. The antenna device according to claim 10 , further comprising:
a bracket that fixes the housing on the cover member arranged to cover a front region of outside the device and defines a direction in which the electromagnetic wave is transmitted outside the device.
15. The antenna device according to claim 14 , wherein
the bracket fixes the housing on the cover member so as to make the direction in which the electromagnetic wave is transmitted outside the device horizontal to a ground.
16. The antenna device according to claim 14 , wherein
the bracket is made of an electromagnetic wave absorber or material containing the electromagnetic wave absorber.
17. The antenna device according to claim 1 , further comprising:
a signal processing unit that estimates an azimuth of a target based on a reflected wave from the target that is a part of the electromagnetic wave transmitted from the transmitting antenna.
18. The antenna device according to claim 17 , wherein
the signal processing unit and the transmitting antenna or the receiving antenna are integrally mounted on the board surface of the circuit board.
19. The antenna device according to claim 1 , wherein
the reflector is made of a metal member or a resin member with a surface coated with metal plating.
20. The antenna device according to claim 1 mounted in a vehicle.