Antenna and wireless communication unit

1. An antenna, comprising:

a first resonator extending in a length direction between two ends thereof, the two ends of the first resonator being a first end and a second end, the first end being an open end;

a second resonator extending in a length direction between two ends thereof, the two ends of the second resonator being a third end and a fourth end, the third end being an open end, the first resonator and the second resonator being disposed substantially parallel with each other, such that the length directions of the first and second resonator are substantially parallel with each other, the first end and the third end being at a same side in the substantially parallel length directions and facing each other, the second end and the fourth end being at a same side in the substantially parallel length directions and facing each other; and

a first capacitor connected between the first end and the third end.

2. The antenna according to claim 1 , wherein each of the first resonator and the second resonator allows a signal to propagate based on a resonance mode in which a current direction in the first resonator is opposite to that in the second resonator.

3. The antenna according to claim 1 , wherein each of the first resonator and the second resonator is a planar waveguide type resonator having a conductor line, the first capacitor is configured with a pair of conductor electrode patterns each provided at a respective one of the first end and the third end.

4. The antenna according to claim 1 , wherein the first capacitor is a capacitor device which is, as a discrete component, independent from the first resonator and the second resonator.

5. The antenna according to claim 1 , further comprising a second capacitor,

wherein

the first resonator is a first half-wavelength resonator,

the second resonator is a second half-wavelength resonator,

the second end is an open end,

the fourth end is an open and, and

the second capacitor is connected between the second end and the fourth end.

6. The antenna according to claim 5 , wherein the first half-wavelength resonator is connected, at a position, to a first end of a signal source, the position being away from a resonance center position of the first half-wavelength resonator by a predetermined distance, and the signal source being grounded at a second end thereof.

7. The antenna according to claim 5 , wherein the first half-wavelength resonator is connected, at a position, to a first end of a signal source, the position being away from a resonance center position of the first half-wavelength resonator by a predetermined distance, and the signal source being connected to the second half-wavelength resonator at a resonance center position thereof.

8. The antenna according to claim 1 , wherein

the first resonator is a first quarter-wavelength resonator and the second end being a short-circuit end, and

the second resonator is a second quarter-wavelength resonator and the fourth end being a short-circuit end.

9. The antenna according to claim 8 , wherein the first quarter-wavelength resonator is connected, at a position, to a first end of a signal source, the position being away from the short-circuit end of the first quarter-wavelength resonator by a predetermined distance, and the signal source being grounded at a second end thereof.

10. A wireless communication unit, comprising:

a first antenna transmitting a signal; and

a second antenna receiving the signal transmitted from the first antenna,

the first antenna including:

a first resonator extending in a length direction between two ends thereof, the two ends of the first resonator being a first end and a second end, the first end being an open end;

a second resonator extending in a length direction between two ends thereof, the two ends of the second resonator being a third end and a fourth end, the third end being an open end, the first resonator and the second resonator being disposed substantially parallel with each other such that the length directions of the first and second resonator are substantially parallel with each other, the first end and the third end being at a same side in the substantially parallel length directions and facing each other, the second end and the fourth end being at a same side in the substantially parallel length directions and facing each other; and

a first capacitor connected between the first end and the third end.

11. The wireless communication unit according to claim 10 , wherein the second antenna includes:

a third resonator extending in a length direction between two ends thereof, the two ends of the third resonator being a fifth end and a sixth end, the fifth end being an open end;

a fourth resonator extending in a length direction between two ends thereof, the two ends of the fourth resonator being a seventh end and a eighth end, the seventh end being an open end, the third resonator and the fourth resonator being disposed substantially parallel with each other such that the length directions of the third and fourth resonators are substantially parallel with each other, the fifth end and the seventh end being at a same side in the substantially parallel length directions and facing each other, the sixth end the eighth end being at a same side in the substantially parallel length directions and facing each other; and

a third capacitor connected between the fifth end and the seventh end,

the first antenna receiving a signal transmitted from the second antenna, the second antenna transmitting the signal to the first antenna, thereby performing a bidirectional communication through transmitting-receiving the signal between the first antenna and the second antenna.