A transmission line structure includes a first transmission line having a first and a second extending line segments and a first and a second line segments extending along a first direction and a third line segment extending along a second direction, and a second transmission line having a third and a fourth extending line segments, a fourth and a fifth line segments extending along the first direction and a sixth line segment extending along the second direction. The first and the second extending line segment are connected to ends of the first and the second line segment. The third line segment is connected to sides of the first and the second line segment. The third and the fourth extending line segment are connected to ends of the fourth the fifth line segment. The sixth line segment is connected to sides of the fourth and the fifth line segment.