Multi-resonant antenna
View Patent ↗A multi-resonant antenna is provided with a main antenna and an additional radiation element. The main antenna is provided with a main portion, which forms a split ring, and a feeding portion, which branches off from the main portion. The additional radiation element extends outward of the main antenna from the main antenna.
1. A multi-resonant antenna comprising:
a substrate having a pattern formed thereon;
a main antenna; and
an additional radiation element,
wherein:
the main antenna comprises a main portion, which forms a split ring, and a feeding portion, which branches off from the main portion;
the additional radiation element extends outward of the main antenna from the main antenna;
the main antenna forms a first resonance portion;
the first resonance portion comprises an LC resonance circuit;
the additional radiation element forms at least a part of a second resonance portion different from the first resonance portion;
the main portion of the main antenna is formed of a combination of (i) at least one part of the pattern formed on the substrate and (ii) a metal member which is distinct from the substrate and mounted on the substrate, at least one portion of the metal member being separated from the substrate.
2. The multi-resonant antenna as recited in claim 1 , wherein:
the multi-resonant antenna comprises a ground portion; and
the additional radiation element does not overlap with the ground portion in a plan view.
3. The multi-resonant antenna as recited in claim 2 , wherein:
the additional radiation element has a first extension portion extending in a first predetermined direction; and
the ground portion has a second extension portion which is apart from the first extension portion in a second predetermined direction perpendicular to the first predetermined direction and which extends in the first predetermined direction.
4. The multi-resonant antenna as recited in claim 3 , wherein:
the ground portion has a third extension portion extending from the second extension portion in the second predetermined direction; and
the first extension portion of the additional radiation element has a tip which is apart from and faces the third extension portion in the first predetermined direction.
5. The multi-resonant antenna as recited in claim 1 , wherein the additional radiation element extends from the main portion of the main antenna.
6. The multi-resonant antenna as recited in claim 1 , wherein the additional radiation element is formed of at least another part of the pattern formed on the substrate.
7. The multi-resonant antenna as recited in claim 1 , wherein:
the main portion of the main antenna has a first end portion and a second end portion;
the feeding portion branches off from the main portion of the main antenna at a position closer to the first end portion than to the second end portion; and
the additional radiation element extends from the main portion of the main antenna at a position closer to the first end portion than to the second end portion, or extends from the feeding portion.
8. The multi-resonant antenna as recited in claim 2 , wherein the ground portion is integrally formed with the main portion of the main antenna.
9. The multi-resonant antenna as recited in claim 2 , wherein the ground portion is formed of at least one part of the pattern formed on the substrate.