The invention particularly relates to an antenna for realizing quasi-
diffraction-free
beamforming and scanning, which comprises a phase shift metasurface and a
feed horn antenna, and is characterized in that the
feed horn antenna directly faces the center of the phase shift metasurface; the phase shift metasurface is of a double-layer
dielectric substrate structure with an electromagnetic wave phase shift function, the whole phase shift metasurface is composed of a plurality of phase shift units arranged periodically, and the structure of each phase shift unit comprises an upper layer
metal patch, a middle layer
metal patch, a lower layer
metal patch, an upper layer
dielectric substrate and a lower layer
dielectric substrate; the phase shift unit is equivalent to a low-pass filtering phase shifter with a phase shift effect,
insertion phase shift at different angles can be realized at any position of the phase shift metasurface by setting the sizes of the three
layers of metal patches in each phase shift unit on the phase shift metasurface, and then the
insertion phase shift at different angles can be realized under the
irradiation of the
feed horn antenna. And generating phase distribution meeting the ideal
phasor shift quantity of the quasi-non-
diffraction beam on the outlet surface of the phase shift metasurface so as to generate the quasi-non-
diffraction beam. According to the invention, the problem that the starting point of the non-diffraction region of the quasi-non-diffraction wave beam is uncontrollable is solved.