The invention discloses a low-RCS antenna, which comprises an artificial surface plasmon coupling medium and a feeding structure, the feeding structure comprises a monopole antenna and a ground plane,and the monopole antenna is arranged on the ground plane; the artificial surface plasmon coupling medium is arranged on the ground plane; and the artificial surface plasmon coupling medium comprisesa periodic metal cell array and a dielectric substrate, and the periodic metal cell array is arranged on the surface of the dielectric substrate. Thus, the low-RCS antenna provide by the embodiment ofthe present invention adjusts and controls the strong-weak dispersion region in the artificial surface plasmon dispersion curve, so that when the antenna is in the weak dispersion region, electromagnetic waves can be efficiently transmitted and radiated along the coupling medium; and when the antenna is in the strong dispersion region, the electromagnetic waves are strongly absorbed. The antennais simple in structure, adopts a printed circuit board technology to process, and is low in cost and easy to be conformal, and on the premise of ensuring the efficient receiving/transmitting performance, an RCS reduction effect is obvious, and a good RCS reduction effect is achieved even in a relatively large angular domain.