An antenna comprises: a circuit board; an antenna radiator, wherein the antenna radiator is provided with a first gap, a second gap, a first grounding piece, a second grounding piece and a feed piece, the first gap and the second gap forming a first inverted-F antenna connected to the first grounding piece and a second inverted-F antenna connected to the second grounding piece on the antenna radiator, and the feed piece being respectively connected to the first inverted-F antenna and the second inverted-F antenna; and an antenna frequency reconstruction system, wherein the antenna frequency reconstruction system is provided on the circuit board, the antenna frequency reconstruction system is respectively connected to the first grounding piece and the second grounding piece and is grounded, and the antenna frequency reconstruction system switches one of the first grounding piece and the second grounding piece to be grounded. Also provided are an antenna radiator and a mobile terminal.