A compact dual-band triple-polarized antenna based on shielded mushroom structures includes a vertically-polarized radiator and a horizontally-polarized radiator. Two parts are fixedly connected in a disc-shaped structure. The vertically-polarized radiator and the horizontally-polarized radiator are both multilayer structures. Each multilayer structure includes a plurality of concentric circles, and the plurality of concentric circles include a plurality of dielectric substrates. The vertically-polarized radiator and horizontally-polarized radiator each include a plurality of shielded mushroom cell structures. Each shielded mushroom cell structure includes at least three metal layers and a metallic shorting pin, and the metallic shorting pin connects at least two of the at least three metal layers. By controlling dispersion properties of the each shielded mushroom cell structure, a multi-frequency pattern diversity device possessing both vertical polarization and dual horizontal polarization radiation characteristics in two pre-defined frequencies is designed.