BALUN FILTER

A Balun filter is disposed on a circuit board, and includes a first wire, a second wire, a third wire and a ground plane. The first wire has one end for disposing a first feeding point. The second wire has one end for disposing a second feeding point. The third wire is configured for disposing a third feeding point and includes a first coupling section, a second coupling section, a first central section and a second central section. The third feeding point is located between the first central section and the second central section, and the first coupling section, the first central section, the second central section and the second coupling section are electrically connected in sequence. In a parallel direction of the first wire, the first feeding point and the second feeding point are located in two opposite directions, respectively, relative to the third feeding point.