The present invention relates to the technical field of
microwave antennas and discloses a circular
polarizer with switchable polarization. The circular
polarizer comprises an upper structure and a lower structure. According to the lower structure,
metal grids are formed by arranging a plurality of
metal lines with gaps, the
metal grids are printed on
dielectric plates, and the
dielectric plates are bonded to foam
layers. According to the upper structure, metal
meander line structures are formed by arranging multiple metal
meander lines with gaps, the metal
meander line structures are printedon three
layers of
dielectric plates, and the three dielectric plates and two foam
layers are bonded to each other. Both the upper structure and the lower structure are coaxial disk structures, and the upper structure can rotate around an axis relative to the lower structure. By rotating the structure of the
polarizer, the arbitrary conversion of a linearly polarized wave to left and right circularly polarized
waves is achieved, or the polarization form of an original electromagnetic wave is not changed. In addition, according to the design of the two-layer structure, the interaction between the antenna structure and
meander line circular polarizer is eliminated, the shaft ratio performance of an antenna is improved, and the polarization conversion efficiency is improved.