Wideband antenna

A wideband antenna comprising:

• a radiation element symmetric to a reference direction, the radiation element having a top edge, a bottom edge, a first side edge, and a second side edge, wherein a width of the radiation element increases along the reference direction;
• a first extension element and a second extension element respectively extending toward the reference direction from two ends of the top edge, the first extension element and the second extension element being mirror-symmetric to each other with respect to the reference direction, wherein a first bevel edge and a second bevel edge of the first extension element intersect with each other to form a first open end, a third bevel edge and a fourth bevel edge of the second extension element intersect with each other to form a second open end, widths of the first extension element and the second extension element smoothly and gradually decrease along the reference direction, and a length of the top edge is greater than a distance between the first open end and the second open end;
• a first reflection element and a second reflection element respectively opposite to the first side edge and the second side edge, the first reflection element and the second reflection element being mirror-symmetric to each other with respect to the reference direction, wherein the first reflection element and the second reflection element reflect electromagnetic energy radiated by the radiation element;
• and
• a feeding element connected to the bottom edge, the feeding element having a feeding point.