Wide-band antenna

A wide-band antenna mounted on a circuit board, comprising:

• an elongated ground plate perpendicularly connected to one side edge of the circuit board;
• an elongated radiating plate perpendicularly connected to the other side edge of the circuit board and facing to the ground plate;
• and
• a planar antenna element disposed on the circuit board, comprising
• a substantially base plate having a first longitudinal edge and a second longitudinal edge opposite to each other, a first transverse edge and a second transverse edge opposite to each other, the first longitudinal edge spaced from and adjacent to the ground plate, the second longitudinal edge connected to an inside of the radiating plate, one end of the first longitudinal edge defining a long gap extending longitudinally to penetrating the second transverse edge, and a longitudinal first coupling portion being correspondingly formed, the base plate defining a longitudinal slot adjacent to the gap and penetrating the second transverse edge, a first strip formed between the gap and the longitudinal slot, a second strip extended perpendicularly to approach to the ground plate from a distal end of the first strip, an inductance portion formed by the first strip and the second strip;
• an extending plate extended outward from a substantially middle portion of the first transverse edge;
• and
• an elongated ground portion extended in the same direction as the extending plate from a distal end of the second strip and connected to an inside of the ground plate, the first coupling portion and the ground portion having a narrow and long interspace to form a capacitive coupling therebetween, a groove being formed among the first strip, the second strip and the ground portion to form a simulation inductance thereamong.