Antenna having radiation patch

An antenna, comprising:

• a dielectric substrate, and a radiation patch and a waveguide feed structure, which are respectively disposed on two opposite sides of the dielectric substrate, wherein
• an orthographic projection of a first transmission port of the waveguide feed structure on the dielectric substrate at least partially overlaps an orthographic projection of the radiation patch on the dielectric substrate;
• and
• the radiation patch is configured to convert a linearly polarized radiation signal transmitted via the first transmission port into a circularly polarized radiation signal,
• wherein the radiation patch comprises a first patch and a second patch, which are connected to each other and disposed in the same layer;
• the first patch is configured to decompose the linearly polarized radiation signal transmitted via the first transmission port into a first linearly polarized sub-signal and a second linearly polarized sub-signal which are orthogonal and have no phase difference;
• and the second patch is configured to form the circularly polarized radiation signal from the first linearly polarized sub-signal and the second linearly polarized sub-signal, and
• wherein the second patch is configured to change the phase difference between the first linearly polarized sub-signal and the second linearly polarized sub-signal to 90° or 270°.