The present invention relates to an antenna based on a metamaterial and a method for generating an operating wavelength of a metamaterial panel. The antenna comprises a radiation source, and a metamaterial panel capable of converging an electromagnetic wave and operating at a first wavelength. The metamaterial panel is adapted to convert the electromagnetic wave radiated from the radiation source into a plane wave and to enable the antenna to simultaneously operate at a second wavelength and a third wavelength which are smaller than the first wavelength and are different multiples of the first wavelength. The present invention further provides a method for generating an operating wavelength of a metamaterial panel for use in the aforesaid antenna. These improve the convergence performance and reduce the volume and size of the antenna.