Antenna system and mobile terminal

An antenna system applied to a mobile terminal, the mobile terminal comprising:

• a back shell having a metal frame;
• a main board received in the back shell;
• and
• an antenna unit provided between the back shell and the main board,
• wherein the main board comprises a front surface facing right towards the antenna unit and a back surface arranged opposite to and spaced apart from the front surface,
• the mobile terminal further comprises a first metal ground layer and a first electrode plate that are provided on the front surface, and a second metal ground layer and a second electrode plate that are provided on the back surface, the first electrode plate is spaced apart from the first metal ground layer and connected to the antenna unit, the second electrode plate is spaced apart from the second metal ground layer and connected to the metal frame, the first electrode plate and the second electrode plate are arranged opposite to and spaced apart from each other to form a capacitor structure, and the first electrode plate is provided with a feeding point that communicates with an external power source.