The invention discloses an ultra-wide-band wave-
trapping antenna which comprises a base plate, a
ground plate located on the back face of the base plate, a reversed-U-shaped parasitic open circuit
branch knot,
antenna radiation patches, antenna feeders and reversed-U-shaped gaps, wherein the
antenna radiation patches, the antenna feeders and the reversed-U-shaped gaps are located on the front face of the base plate. A reversed-U-shaped wide slot is formed in the middle of the
ground plate, the reversed-U-shaped parasitic open circuit
branch knot is arranged inside the reversed-U-shaped wide slot, and
coupling distances are reserved between reversed-U-shaped parasitic open circuit
branch knot and the edges of the reversed-U-shaped wide slot. The antenna feeders are arranged on the middle lower portion of the base plate. The projections of the
antenna radiation patches on the
ground plate are located on the middle lower portion of the reversed-U-shaped wide slot, the reversed-U-shaped gaps are formed in the outer edges of the antenna
radiation patches, and
coupling distances are formed between the reversed-U-shaped gaps and the outer edges of the antenna
radiation patches. A circle where the projections of the antenna
radiation patches and the projections of the arc parts of the reversed-U-shaped gaps on the ground plate locate is concentric with the circle where the reversed-U-shaped wide slot and the arc part of the reversed-U-shaped parasitic open circuit branch knot locate. By loading the reversed-U-shaped gaps and the reversed-U-shaped parasitic open circuit branch knot simultaneously, the ultra-wide-band wave-
trapping antenna has a wave
trapping stop band which is good in rectangular degree, flat in stop band and controllable in
band width.