Defected ground structure with shielding effect

A defected ground structure with a shielding effect, comprising:

• a dielectric layer, having a first surface and a second surface opposite to the first surface;
• a defected metal layer, disposed in the dielectric layer and located between the first surface and the second surface, and having a line-shaped opening;
• a grounded metal layer, disposed on the second surface;
• and
• at least one conductive mushroom-like structure, disposed between the defected metal layer and the grounded metal layer, arranged along an extending direction of the line-shaped opening periodically, and the conductive mushroom-like structure comprising:
• a fungating part, parallel to the defected metal layer, and a distance being maintained between the fungating part and the defected metal layer, wherein a projection area of the fungating part on the defected metal layer covers a portion of the line-shaped opening corresponding to the projection area of the fungating part;
• and
• a stipe part, connecting the fungating part and the grounded metal layer.