Antenna device

1. An antenna device, comprising:

a first antenna, comprising:

a first insulating layer;

a first signal-feeding line, disposed on a first surface of the first insulating layer; and

two first grounding lines, disposed on a second surface of the first insulating layer, wherein the first surface and the second surface of the first insulating layer are opposite to each other, and the first grounding lines are symmetrical with respect to a first axis on the first insulating layer;

a second antenna, comprising:

a second insulating layer;

a second signal-feeding line, disposed on a first surface of the second insulating layer; and

two second grounding lines, disposed on a second surface of the second insulating layer, wherein the first surface and the second surface of the second insulating layer are opposite to each other, and the second grounding lines are symmetrical with respect to a second axis on the second insulating layer; and

a circuit board;

wherein the first insulating layer and the second insulating layer intersect at about 90 degrees, the first antenna and the second antenna are disposed on a top surface of the circuit board, and the first axis and the second axis are adjacent and substantially parallel to each other.

2. The antenna device according to claim 1 , wherein the first axis and the second axis substantially coincide.

3. The antenna device according to claim 2 , wherein the first signal-feeding line comprises a first end and a second end, each of the first grounding lines comprises a first end and a second end, the first end of the first signal-feeding line is for wireless signal reception matching with the first end of each of the first grounding lines in a first frequency band, and the second end of the first signal-feeding line is for wireless signal reception matching with the second end of each of the first grounding lines in a second frequency band.

4. The antenna device according to claim 3 , wherein the first insulating layer has a side surface that is away from the circuit board and connects the first surface and the second surface of the first insulating layer, the first end of the first signal-feeding line is adjacent to the side surface of the first insulating layer, the second end of the first signal-feeding line is adjacent to the side surface of the first insulating layer, and the second end of the first signal-feeding line is more adjacent to the side surface of the first insulating layer than the first end of the first signal-feeding line.

5. The antenna device according to claim 4 , wherein a distance between the first end of the first signal-feeding line and the side surface of the first insulating layer is smaller than ⅓ of a distance between the side surface of the first insulating layer and the circuit board, and a distance between the second end of the first signal-feeding line and the side surface of the first insulating layer is smaller than ⅓ of the distance between the side surface of the first insulating layer and the circuit board.

6. The antenna device according to claim 3 , wherein the second signal-feeding line comprises a first end and a second end, each of the second grounding lines comprises a first end and a second end, the first end of the second signal-feeding line is for wireless signal reception matching with the first end of each of the second grounding lines in the first frequency band, and the second end of the second signal-feeding line is for matching with the second end of each of the second grounding lines in the second frequency band.

7. The antenna device according to claim 6 , wherein the second insulating layer has a side surface that is away from the circuit board and connects the first surface and the second surface of the second insulating layer, the first end of the second signal-feeding line is adjacent to the side surface of the second insulating layer, the second end of the second signal-feeding line is adjacent to the side surface of the second insulating layer, and the second end of the second signal-feeding line is more adjacent to the side surface of the second insulating layer than the first end of the second signal-feeding line.

8. The antenna device according to claim 7 , wherein a distance between the first end of the second signal-feeding line and the side surface of the second insulating layer is smaller than ⅓ of a distance between the side surface of the second insulating layer and the circuit board, and a distance between the second end of the second signal-feeding line and the side surface of the second insulating layer is smaller than ⅓ of the distance between the side surface of the second insulating layer and the circuit board.

9. The antenna device according to claim 1 , wherein a shortest distance between the first grounding lines is between 0 and 10 mm.

10. The antenna device according to claim 1 , wherein a shortest distance between the second grounding lines is between 0 and 10 mm.

11. The antenna device according to claim 1 , wherein the first axis and the second axis are substantially perpendicular to the first surface of the circuit board.

12. The antenna device according to claim 1 , further comprising a reflecting board, disposed on a second surface of the circuit board, wherein the first surface and the second surface of the circuit board are opposite to each other.

13. The antenna device according to claim 1 , wherein a shape and a location of the first signal-feeding line on the first insulating layer are respectively similar to a shape and a location of the second signal-feeding line on the second insulating layer, and a shape and a location of the first grounding lines on the first insulating layer are respectively similar to a shape and a location of the second grounding lines on the second insulating layer.