Coupler and electronic apparatus

1. A card device capable of being inserted into a card slot in a housing of an electronic apparatus, the card device comprising a coupler for transmitting and receiving an electromagnetic wave by electromagnetic coupling between the coupler and another coupler, the coupler being configured to be used for close proximity wireless transfer, the coupler comprising:

a line-shaped coupling element comprising a first open end and a second open end, wherein each of the first open end and the second open end is not connected to any conductive member;

a ground plane;

a feeding element connecting the coupling element and a feed point, the feeding element comprising

a first end connected to an intermediate point of the coupling element between the first open end and the second open end, wherein a length between the intermediate point and the first open end is equal to a length between the intermediate point and the second open end, and

a second end connected to the feed point; and

a first short circuiting element connecting the feeding element and the ground plane, the first short circuiting element comprising

a third end between the first end and the second end of the feeding element, and

a fourth end connected to a short circuiting point on the ground plane

wherein a shape of the coupling element is symmetric with respect to the intermediate point of the coupling element,

wherein the card device is capable of being removably inserted into the card slot from outside the housing, the card slot having an opening on the housing, the card slot being based on a specific general purpose card standard,

wherein the card device comprises one end at which a connector configured to interface with the electronic apparatus is arranged and another end, and

wherein the coupling element is positioned on a side of other end of the card device such that the coupling element is positioned on a side of the opening of the card slot when the card device is inserted into the card slot.

2. The card device of claim 1 , wherein an electric length from the feed point to each of the first open end and the second open end is ¼ of a wavelength corresponding to a center frequency of the electromagnetic wave.

3. The card device of claim 1 , wherein the coupler further comprises a substrate,

wherein the coupling element is in a first area on a first surface of the substrate, and

wherein the ground plane is in a second area on the first surface of the substrate or in a third area on a second surface of the substrate, the third area on the second surface being distinct from the first area of the first surface when the third area of the second surface and the first area of the first surface are projected onto a single plane.

4. A card device capable of being inserted into a card slot in a housing of an electronic apparatus, the card device comprising a coupler for transmitting and receiving an electromagnetic wave by electromagnetic coupling between the coupler and another coupler, the coupler being configured to be used for close proximity wireless transfer, the coupler comprising:

a substrate;

a line-shaped coupling element in a first area on a first surface of the substrate, the coupling element comprising a first open end and a second open end, wherein each of the first open end and the second open end is not connected to any conductive member;

a ground plane in a second area on the first surface of the substrate or in a third area on a second surface of the substrate, the third area on the second surface being distinct from the first area of the first surface when the third area of the second surface and the first area of the first surface are projected onto a single plane;

a feeding element on the substrate connecting the coupling element and a feed point, the feeding element comprising

a first end connected to an intermediate point of the coupling element between the first open end and the second open end, wherein a length between the intermediate point and the first open end is equal to a length between the intermediate point and the second open end, and

a second end connected to the feed point; and

a first short circuiting element on the substrate connecting the feeding element and the ground plane, the first short circuiting element comprising

a third end between the first end and the second end of the feeding element, and

a fourth end connected to a short circuiting point on the ground plane,

wherein a shape of the coupling element is symmetric with respect to the intermediate point of the coupling element,

wherein the card device is capable of being removably inserted into the card slot from outside the housing, the card slot having an opening on the housing, the card slot being based on a specific general purpose card standard,

wherein the card device comprises one end at which a connector configured to interface with the electronic apparatus is arranged and other end, and

wherein the coupling element is positioned on a side of the other end of the card device such that the coupling element is positioned on a side of the opening of the card slot when the card device is inserted into the card slot.

5. The card device of claim 4 , wherein an electric length from the feed point to each of the first open end and the second open end is ¼ of a wavelength corresponding to a center frequency of the electromagnetic wave.

6. The card device of claim 4 ,

further comprising a communication module electrically connected to the coupler,

wherein the communication module is provided on the substrate of the coupler.

7. An electronic apparatus comprising:

a housing comprising a card slot therein;

a card device capable of being inserted into the card slot, the card device comprising a coupler for transmitting and receiving an electromagnetic wave by electromagnetic coupling between the coupler and another coupler, the coupler being configured to be used for close proximity wireless transfer;

a communication module in the housing or the card device, the communication module being electrically connected to the coupler; and

a processor in the housing, configured to execute an application for performing communication control using the communication module;

wherein the coupler comprises:

a substrate;

a line-shaped coupling element in a first area on a first surface of the substrate, the coupling element including a first open end and a second open end, wherein each of the first open end and the second open end is not connected to any conductive member;

a ground plane arranged in a second area on the first surface of the substrate or in a third area on a second surface of the substrate, the third area on the second surface being distinct from the first area of the first surface when the third area of the second surface and the first area of the first surface are projected onto a single plane;

a feeding element on the substrate connecting the coupling element and a feed point, the feeding element comprising

a first end connected to an intermediate point of the coupling element between the first open end and the second open end, wherein a length between the intermediate point and the first open end is equal to a length between the intermediate point and the second open end, and

a second end connected to the feed point; and

a first short circuiting element on the substrate connecting the feeding element and the ground plane, the first short circuiting element comprising

a third end between the first end and the second end of the feeding element, and

a fourth end connected to a short circuiting point on the ground plane

wherein a shape of the coupling element is symmetric with respect to the intermediate point of the coupling element,

wherein the card device is capable of being removably inserted into the card slot from outside the housing, the card slot having an opening on the housing, the card slot being based on a specific general purpose card standard,

wherein the card device comprises one end at which a connector configured to interface with the electronic apparatus is arranged and other end, and

wherein the coupling element is positioned on a side of the other end of the card device such that the coupling element is positioned on a side of the opening of the card slot when the card device is inserted into the card slot.

8. The electronic apparatus of claim 7 , wherein the communication module is on the substrate in the card device.

9. The electronic apparatus of claim 7 , wherein the card device comprises one end at which a connector is arranged and other end, and

wherein the coupler is arranged in the card device such that the coupling element is positioned on a side of the other end of the card device.

10. The card device of claim 1 , wherein the coupler further comprises

a second short circuiting element connecting the feeding element and the ground plane, the second short circuiting element comprising

a fifth end, and

a sixth end, wherein the fifth end is connected to the third end and the sixth end is connected to the ground plane and the second short circuiting element is on an opposite side of the first short circuiting element with respect to the feeding element.

11. The card device of claim 4 , wherein the coupler further comprises

a second short circuiting element connecting the feeding element and the ground plane, the second short circuiting element comprising

a fifth end, and

a sixth end, wherein the fifth end is connected to the third end and the sixth end is connected to the ground plane and the second short circuiting element is on an opposite side of the first short circuiting element with respect to the feeding element.

12. The electronic apparatus of claim 7 , wherein the coupler further comprises a second short circuiting element connecting the feeding element and the ground plane, the second short circuiting element comprising

a fifth end, and

a sixth end, wherein the fifth end is connected to the third end and the sixth end is connected to the ground plane and the second short circuiting element is on an opposite side of the first short circuiting element with respect to the feeding element.