Polarization conversion structure and antenna

A polarization conversion structure, comprising a ground structure layer, a first dielectric substrate and a radiation structure layer which are stacked in a direction perpendicular to a plane where the polarization conversion structure is located;

• wherein
• the radiation structure layer comprises at least one radiation unit, the radiation unit comprises a radiation structure, the radiation structure is symmetrical with respect to a first centerline, and the first centerline is a centerline of the radiation structure extending in a fourth direction on a plane parallel to the polarization conversion structure;
• and orthographic projections of the radiation unit and the ground structure layer on the first dielectric substrate are at least partially overlapped,
• wherein the radiation unit further comprises a resonant structure spaced apart from the radiation structure, the resonant structure is located around the radiation structure to form an annular structure, the resonant structure comprises a resonant opening, and the annular structure is disconnected at a position of the resonant opening,
• wherein a shape of an outer contour of the resonant structure is a square, and resonant openings are located at at least one set of opposite corners of the square, or the resonant openings are located at at least one set of opposite sides of the square;
• on a plane parallel to the polarization conversion structure, a set of opposite sides of the resonant structure extend in a first direction and another set of opposite sides of the resonant structure extend in a second direction, the resonant structure is symmetrical with respect to a third centerline and a fourth centerline, wherein the third centerline is a centerline of the resonant structure extending in the first direction and the fourth centerline is a centerline of the resonant structure extending in the second direction, wherein, the first direction, the second direction and the fourth direction intersect with each other,
• wherein a plurality of radiation structures among the plurality of radiation units are arranged in a uniform manner,
• wherein the polarization conversion structure is shaped as a square, the polarization conversion structure comprises a first sub-array to a fourth sub-array defined by a ninth centerline and a tenth centerline, a plurality of radiation structures located in the first sub-array is arranged in a same manner with a plurality of radiation structures located in a third sub-array, a plurality of radiation structures located in a second sub-array is arranged in a same manner with a plurality of radiation structures located in the fourth sub-array, on a plane parallel to the polarization conversion structure, one set of opposite sides of the polarization conversion structure extend in the first direction and another set of opposite sides of the polarization conversion structure extend in the second direction, the ninth centerline is a centerline of the polarization conversion structure extending in the first direction, and the tenth centerline is a centerline of the polarization conversion structure extending in the second direction, wherein the first direction, the second direction, a third direction intersect with the fourth direction,
• wherein the plurality of radiation units are disposed symmetrically with respect to the ninth centerline, the tenth centerline, a seventh centerline, and an eighth centerline, the seventh centerline is a centerline of the polarization conversion structure extending in the third direction and the eighth centerline is a centerline of the polarization conversion structure extending in the fourth direction on a plane parallel to the polarization conversion structure.