Circuit board

1. A circuit board comprising:

a substrate;

a first power feed line disposed so as to be close to a plurality of radiating elements provided on a surface of the substrate and to extend in a first direction;

a first connection conductor extending in a second direction orthogonal to the first direction and orthogonal to the surface of the substrate, one end of the first connection conductor being connected to the first power feed line substantially at a central portion of the first power feed line in the first direction; and

a second power feed line that has a first line part extending in a third direction orthogonal to the second direction, the first line part connecting to another end of the first connection conductor, and also has a second line part branching from the first line part, the second line part connecting to the another end along the third direction.

2. The circuit board according to claim 1 , wherein a line length of the second line part is determined according to an integer multiple of an effective wavelength of an alternate current to be supplied to the first line part.

3. The circuit board according to claim 2 , further comprising a stub positioned within a distance equal to a half of the effective wavelength from a node located between the first line part and the second line part, the stub being provided on the first line part.

4. The circuit board according to claim 1 , wherein a thickness of the substrate in the second direction is at least a half of an effective wavelength of an alternate current to be supplied to the first line part.

5. The circuit board according to claim 1 , wherein at least the first power feed line and the first line part of the second power feed line are each a linear conductor.

6. The circuit board according to claim 1 , further comprising a ground layer.

7. The circuit board according to claim 1 , wherein the first direction and the third direction are essentially the same direction.

8. The circuit board according to claim 1 , wherein the first connection conductor is manufactured by plating a through-hole.

9. The circuit board according to claim 1 , wherein a line width of the second line part is larger than a line width of the first line part.

10. The circuit board according to claim 1 , further comprising wiring layers and second connection conductors, which are formed so as to be substantially symmetric with respect to a plane perpendicular to both the first power feed line and the second power feed line, which are linked together by the first connection conductor.

11. The circuit board according to claim 1 , wherein the first direction is a direction along which the plurality of radiating elements are arranged.

12. The circuit board according to claim 1 , wherein the first power feed line is disposed on the surface of the substrate.

13. The circuit board according to claim 1 , wherein the second line part connects to the another end along the third direction from a side opposite from a side of the first line part.

14. The circuit board according to claim 13 , wherein the second line part curves around the another end and connects to the another end from the side opposite from the side of the first line part.

15. The circuit board according to claim 1 , further comprising:

wiring layers, and

one or more second connection conductors extending in the second direction to connect between the wiring layers.

16. The circuit board according to claim 15 , wherein the wiring layers are ground layers.