Antenna device of mobile terminal

1. An antenna device of a mobile terminal, the antenna device comprising:

an antenna module configured to radiate electric waves comprising:

a body, which is an insulation material, and

a radiation pattern functioning as a first radiator of electric waves, formed in the body toward a front surface of the mobile terminal to radiate electric waves toward the front surface in which a display screen of the mobile terminal is disposed;

an internal case made of a first metal material, the internal case having a first slot in a portion of the first metal material and having a housing space for housing the antenna module; and

an external case comprising a rear case formed at a rear surface of the mobile terminal opposite to the front surface of the mobile terminal in which the display screen of the mobile terminal is disposed, the external case made of a second metal material, having a housing space for housing the internal case, and having a second slot in a portion of the metal material,

wherein the second slot is formed in the rear case, in alignment with the first slot of the internal case, and is electrically coupled to each of the radiation pattern of the antenna module and a ground of the mobile terminal such that the rear case is configured to function as a second radiator of electric waves resonating at frequency different of the radiation pattern of the antenna module and in a direction different from that of the radiation pattern of the antenna module.

2. The antenna device of claim 1 , wherein the display screen is a touch screen.

3. The antenna device of claim 1 , wherein the antenna module is housed in the internal case of the mobile terminal and is housed at a position corresponding to the first slot.

4. The antenna device of claim 1 , wherein the antenna module further comprises a power supply pattern for generating a coupling effect with the radiation pattern by supplying a current from a circuit board provided inside the mobile terminal.

5. The antenna device of claim 1 ,

wherein the case comprises the rear case and a front case formed at the front surface, and

at the front case, a radiation area corresponding to a position at which the radiation pattern is formed is made of a non-metal material through which electric waves radiate toward the front surface.

6. The antenna device of claim 1 ,

wherein the external case is separable from the mobile terminal, and

the internal case is electrically connected to each of the antenna module and the ground of the mobile terminal to operate as a radiator through the first slot.

7. The antenna device of claim 6 , wherein, when the external case is separated from the mobile terminal, the internal case includes a structure in which a battery housed in the mobile terminal is separable from the mobile terminal.

8. The antenna device of claim 7 , wherein the internal case includes a structure having a groove through which the battery passes when being removed or installed.

9. The antenna device of claim 7 , wherein the internal case includes a structure that does not cover the battery.

10. The antenna device of claim 1 , wherein the second slot is formed at an edge of the rear case.

11. The antenna device of claim 1 , wherein the second slot is filled with a non-metal material.

12. The antenna device of claim 11 , wherein the non-metal material has the same color as the metal material.

13. The antenna device of claim 1 , wherein a connector, for electrically connecting an external device to a circuit board provided inside the mobile terminal, is exposed to outside the mobile terminal through the second slot.

14. The antenna device of claim 13 , wherein the connector is a universal serial bus (USB) connector.