Antenna device and electronic apparatus

1. An antenna device comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

the coil antenna includes a first coil opening adjacent to an outer edge of the planar first conductive pattern and a second coil opening located inside the outer edge of the planar first conductive pattern.

2. The antenna device according to claim 1 , wherein the connection conductor includes a planar third conductive pattern disposed on the circuit substrate so as to overlap the coil antenna when the connection conductor is seen in plan view, and connecting the planar first conductive pattern and the planar second conductive pattern.

3. The antenna device according to claim 1 , wherein the connection conductor includes a fourth conductive pattern overlapping a portion of the wiring pattern disposed on the circuit substrate of the wiring pattern such that the fourth conductive pattern and the portion of the wiring pattern are isolated from each other, and connecting the planar first conductive pattern and the planar second conductive pattern.

4. The antenna device according to claim 1 , wherein the feed circuit is provided on the circuit substrate.

5. The antenna device according to claim 1 , wherein each of the planar first conductive pattern and the planar second conductive pattern is a ground conductor.

6. An antenna device comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

the connection conductor includes a planar third conductive pattern disposed on the circuit substrate so as to overlap the coil antenna when the connection conductor is seen in plan view, and connecting the planar first conductive pattern and the planar second conductive pattern.

7. The antenna device according to claim 6 , wherein the connection conductor includes a fourth conductive pattern overlapping a portion of the wiring pattern disposed on the circuit substrate of the wiring pattern such that the fourth conductive pattern and the portion of the wiring pattern are isolated from each other, and connecting the planar first conductive pattern and the planar second conductive pattern.

8. The antenna device according to claim 6 , wherein the feed circuit is provided on the circuit substrate.

9. The antenna device according to claim 6 , wherein each of the planar first conductive pattern and the planar second conductive pattern is a ground conductor.

10. An antenna device comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern, and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

each of the planar first conductive pattern and the planar second conductive pattern is a ground conductor.

11. The antenna device according to claim 10 , wherein the connection conductor includes a fourth conductive pattern overlapping a portion of the wiring pattern disposed on the circuit substrate of the wiring pattern such that the fourth conductive pattern and the portion of the wiring pattern are isolated from each other, and connecting the planar first conductive pattern and the planar second conductive pattern.

12. The antenna device according to claim 10 , wherein the feed circuit is provided on the circuit substrate.

13. An electronic apparatus comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

the coil antenna includes a first coil opening adjacent to an outer edge of the planar first conductive pattern and a second coil opening located inside the outer edge of the planar first conductive pattern.

14. The electronic apparatus according to claim 13 , wherein the connection conductor includes a planar third conductive pattern disposed on the circuit substrate so as to overlap the coil antenna when the connection conductor is seen in plan view, and connecting the planar first conductive pattern and the planar second conductive pattern.

15. The electronic apparatus according to claim 13 , wherein the connection conductor includes a fourth conductive pattern overlapping a portion of the wiring pattern disposed on the circuit substrate of the wiring pattern such that the fourth conductive pattern and the portion of the wiring pattern are isolated from each other, and connecting the planar first conductive pattern and the planar second conductive pattern.

16. The electronic apparatus according to claim 13 , wherein the feed circuit is provided on the circuit substrate.

17. The electronic apparatus according to claim 13 , wherein each of the planar first conductive pattern and the planar second conductive pattern is a ground conductor.

18. An electronic apparatus comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

the connection conductor includes a planar third conductive pattern disposed on the circuit substrate so as to overlap the coil antenna when the connection conductor is seen in plan view, and connecting the planar first conductive pattern and the planar second conductive pattern.

19. The electronic apparatus according to claim 18 , wherein the feed circuit is provided on the circuit substrate.

20. An electronic apparatus comprising:

a circuit substrate;

a feed circuit;

a coil antenna mounted on the circuit substrate;

a wiring pattern disposed on the circuit substrate and connecting the coil antenna and the feed circuit;

a planar first conductive pattern disposed on the circuit substrate and located outside a loop current path defined by the coil antenna, the feed circuit, and the wiring pattern when the circuit substrate is seen in plan view;

a planar second conductive pattern disposed on the circuit substrate and located inside the loop current path when the circuit substrate is seen in plan view; and

a connection conductor connecting the planar first conductive pattern and the planar second conductive pattern and disposed on the circuit substrate; wherein

at least one location of the connection conductor or the wiring pattern includes an interlayer connection conductor; and

each of the planar first conductive pattern and the planar second conductive pattern is a ground conductor.