An antenna module includes a hollow cylindrical conductor structure. The hollow cylindrical conductor structure includes a cylinder wall, at least one first slot, and a first feed point. The at least one first slot and the first feed point are located on the cylinder wall. The cylinder wall includes a first end edge and a second end edge opposite to each other. The at least one first slot extends from an internal position of the cylinder wall to the first end edge, and forms a first closed path together with the first end edge. The first feed point is located beside the at least one first slot. The antenna module is adapted to excite a first frequency band through the first closed path.