Antenna device for portable terminal

An antenna device for a portable terminal, the antenna device comprising:

• a circuit board comprising a conductive layer on a surface thereof;
• a slit which is formed by removing a portion of the conductive layer and configured to extend from a side edge of the conductive layer in a direction, an end of the slit is opened to a side edge of the conductive layer and another end of the slit is closed by another portion of the conductive layer;
• a feeding line connected from one side of the slit across the slit to the conductive layer in the other side of the slit and configured to provide a transmission signal from the one side of the slit to the feeding line;
• a connection terminal installed on the conductive layer in the other side of the slit;
• an auxiliary board positioned on the slit to face the surface of the circuit board;
• a connection pattern provided on a surface of the auxiliary board and arranged to contact the connection terminal;
• and
• a radiating element formed on the auxiliary board and electrically connected with the connection pattern,
• wherein the radiating element comprises:
• a first extension portion positioned on the auxiliary board on one side of the slit to extend in parallel with the slit;
• a second extension portion extending from an end of the first extension portion to enclose the closed end of the side of the slit;
• a third extension portion positioned on the auxiliary board on the other side of the slit, at least a portion of which extending from an end of the second extension portion in parallel with the slit;
• a fourth extension portion extending from an end of the third extension portion and parallel to the second extension portion;
• and
• a fifth extension portion extending from an end of the fourth extension portion and parallel to the first and third extension portions, such that a projection of the radiating element on the surface of the circuit board is partially positioned on a circumference of the slit, without covering the slit, when the antenna device is shown on a plane view.