A mobile communication device comprising an antenna structure, the antenna structure comprising: a grounding element, comprising a main ground and a protruded ground, wherein the protruded ground is electrically connected to an edge of the main ground; and an antenna element, disposed on a substrate, the antenna element comprising: a feeding portion, comprising: a feeding point, electrically connected to a signal source being disposed on the grounding element; and a first strip and a second strip, wherein the first strip and the second strip are both connected to the feeding point, open ends of the first strip and the second strip are extended toward opposite directions, a projection is generated by projecting the feeding portion onto a plane where the grounding element is located, and the projection comprises a partial section of the protruded ground; and a radiating portion, comprising: a shorting point, electrically connected to the protruded ground by a short-circuiting strip; and a first open end and a second open end; wherein there is a first coupling gap between the first strip and a first section of the radiating portion having the first open end, and there is a second coupling gap between the second strip and a second section of the radiating portion having the second open end; wherein the main ground and the protruded ground are located on a first plane, the substrate comprises a first partial section and a second partial section forming an L shape, the first partial section of the substrate having the short-circuiting strip is located on a second plane perpendicular to the first plane, and the second partial section of the substrate having the antenna element is located on a third plane parallel to the first plane. a grounding element, comprising a main ground and a protruded ground, wherein the protruded ground is electrically connected to an edge of the main ground; and an antenna element, disposed on a substrate, the antenna element comprising: a feeding portion, comprising: a feeding point, electrically connected to a signal source being disposed on the grounding element; and a first strip and a second strip, wherein the first strip and the second strip are both connected to the feeding point, open ends of the first strip and the second strip are extended toward opposite directions, a projection is generated by projecting the feeding portion onto a plane where the grounding element is located, and the projection comprises a partial section of the protruded ground; and a radiating portion, comprising: a shorting point, electrically connected to the protruded ground by a short-circuiting strip; and a first open end and a second open end; wherein there is a first coupling gap between the first strip and a first section of the radiating portion having the first open end, and there is a second coupling gap between the second strip and a second section of the radiating portion having the second open end; wherein the main ground and the protruded ground are located on a first plane, the substrate comprises a first partial section and a second partial section forming an L shape, the first partial section of the substrate having the short-circuiting strip is located on a second plane perpendicular to the first plane, and the second partial section of the substrate having the antenna element is located on a third plane parallel to the first plane. a feeding portion, comprising: a feeding point, electrically connected to a signal source being disposed on the grounding element; and a first strip and a second strip, wherein the first strip and the second strip are both connected to the feeding point, open ends of the first strip and the second strip are extended toward opposite directions, a projection is generated by projecting the feeding portion onto a plane where the grounding element is located, and the projection comprises a partial section of the protruded ground; and a feeding point, electrically connected to a signal source being disposed on the grounding element; and a first strip and a second strip, wherein the first strip and the second strip are both connected to the feeding point, open ends of the first strip and the second strip are extended toward opposite directions, a projection is generated by projecting the feeding portion onto a plane where the grounding element is located, and the projection comprises a partial section of the protruded ground; and a radiating portion, comprising: a shorting point, electrically connected to the protruded ground by a short-circuiting strip; and a first open end and a second open end; a shorting point, electrically connected to the protruded ground by a short-circuiting strip; and a first open end and a second open end; wherein there is a first coupling gap between the first strip and a first section of the radiating portion having the first open end, and there is a second coupling gap between the second strip and a second section of the radiating portion having the second open end; wherein the main ground and the protruded ground are located on a first plane, the substrate comprises a first partial section and a second partial section forming an L shape, the first partial section of the substrate having the short-circuiting strip is located on a second plane perpendicular to the first plane, and the second partial section of the substrate having the antenna element is located on a third plane parallel to the first plane.