Three-frequency-band multiple-input-multiple-output (MIMO) antenna for 5G and 6G

The invention relates to a three-frequency-band multiple-input-multiple-output (MIMO) antenna for 5G and 6G, which is characterized in that two metal radiation units in mirror symmetry are printed at the top of a cuboid dielectric substrate, and each radiation unit is in axial symmetry and consists of a circular radiation sheet with a cut-out circular ring, an X-shaped microstrip line, a U-shaped microstrip line and a rectangular microstrip line; the antenna is characterized in that the bottom of the substrate is of an axisymmetric fence-shaped metal structure, a T-shaped branch is directly connected to a rectangular structure on the ground, three I-shaped slit structures with different sizes are loaded on the T-shaped branch, and two pairs of small rectangles which are symmetrical in pairs are additionally arranged on the two sides of the T-shaped branch; two symmetrical inverted-T-shaped branches are additionally arranged on the upper side of a rectangle on the ground, two symmetrical L-shaped branches are