Multiband antenna, multiband antenna array, and wireless communications device

1. An antenna comprising:

a conductor reflection plate;

a first antenna element; and

a second antenna element, wherein

the first antenna element and the second antenna element are disposed above the conductor reflection plate; and

an electromagnetic resonance frequency of the first antenna element and an electromagnetic resonance frequency of the second antenna element are different from each other, and

each of the first antenna element and the second antenna element comprises:

a substantially C-shaped conductor of a shape in which a part of a closed shape is discontinuous by a split;

a conductor feed line; and

a conductor feed section, wherein:

a first of the

conductor feed line is electrically connected to one part out of both parts of the substantially C-shaped conductor opposing each other across the split,

a second end of the conductor feed line is extended toward the conductor reflection plate,

a first end of the conductor feed section is continuously connected to an outer edge of the substantially C-shape conductor,

a second end of the conductor feed section is extended toward the conductor reflection plate, and

the conductor feed line and the conductor feed section are opposed to each other and constitute an electric path for feeding power to the substantially C-shaped conductor.

2. The antenna according to claim 1 , further comprising:

a plurality of the first antenna elements, and

a plurality of the second antenna elements,

wherein the plurality of first antenna elements are arranged so as to be aligned with spacing in both a longitudinal direction and a lateral direction in a projected view on a plane that is parallel with the conductor reflection plate, and adjacent ones of the first antenna elements are in a substantial perpendicular relationship, and a lengthwise direction of either one of the adjacent ones of the first antenna elements is oriented to a vicinity of a center in a lengthwise direction of another, and

the plurality of second antenna elements are arranged so as to be aligned with spacing in both a longitudinal direction and a lateral direction in a projected view on a plane that is parallel with the conductor reflection plate, and adjacent ones of the second antenna elements are in a substantial perpendicular relationship, and a lengthwise direction of either one of the adjacent ones of the second antenna elements is oriented to a vicinity of a center in a lengthwise direction of another.

3. A wireless communications device equipped with the antenna according to claim 1 .

4. The antenna according to the claim 1 ,

wherein a connection point of at least one of the first antenna element and the second

antenna element that connects the substantially C-shaped conductor with the conductor feed section is positioned at around a center of the substantially C-shaped conductor.

5. The antenna according to the claim 1 ,

wherein a connection point of at least one of the first antenna element and the second antenna element is positioned, on each side thereof, within ¼ of a lengthwise size in a view from around a center of the C-shaped conductor.

6. The antenna according to the claim 1 ,

wherein at least one of the first antenna element and the second antenna element comprises:

a connection point , wherein the conductor feed line, and the conductor feed section are positioned in a same layer,

wherein the second end of the conductor feed line of at least one of the first antenna element and the second antenna element is extended through an inner part of a slit of a conductor that is shaped by connecting the C-shaped conductor with the conductor feed section.

7. The antenna according to the claim 1 ,

wherein the whole or parts of the conductor feed line of at least one of the first antenna element and the second antenna element is a core wire of a coaxial cable; and

the whole or parts of the conductor feed section of the at least one of the first antenna element and the second antenna element is an external conductor of a coaxial cable.

8. The antenna according to the claim 1 ,

wherein the second end of the conductor feed line, and the second end of the conductor feed section of at least one of the first antenna element and the second antenna element are extended toward a back side of the conductor reflection plate through a hole of the conductor reflection plate.

9. The antenna according to the claim 1 , further comprising:

two of the first antenna elements, and

two of the second antenna elements,

wherein the two of the first antenna elements are respectively in a substantially perpendicular relationship with each other in a projected view on the conductor reflection plate, and

wherein the two of the second antenna elements are respectively in a substantially perpendicular relationship with each other in a projected view on the conductor reflection plate.

10. The antenna according to the claim 9 ,

wherein pairs of the two first antenna elements are arranged in a shape of a lattice along a plane that is substantially parallel with the conductor reflection plate, at a substantially equal interval of substantially ½ of a wavelength of an electro-magnetic wave at a resonance frequency of the first antenna element, and

wherein pairs of the two of the second antenna elements are arranged in a shape of a lattice along a plane that is substantially parallel with the conductor reflection plate, at a substantially equal interval of substantially ½ of a wavelength of an electro-magnetic wave at a resonance frequency of the second antenna element.