A system for diffraction of an electromagnetic wave, comprising: a substrate , set in a space rife of a first medium and made of a second medium; a transmission unit , disposed on the substrate and including a plurality of transmission lines , each said transmission line having a transmission line length that is associated with a first medium operation wavelength that is associated with an operation frequency, and the transmission lines being connected successively; and a plurality of antennas , disposed on the substrate , close to at least some of the transmission lines at positions configured such that the phases of the electromagnetic wave propagating through the corresponding transmission lines at the positions of the antennas are approximate by having a phase difference that is equal to or smaller than 30 degrees, so that each said antenna is able to feed the electromagnetic wave it receives at the operation frequency to corresponding said transmission lines for transmission, and is able to radiate the electromagnetic wave transmitted in corresponding said transmission lines outward at the operation frequency; a plurality of insulating members , wherein the antennas are arranged on the transmission lines , respectively, and the insulating members are disposed between the transmission lines and the antennas , in which each said insulating member is made of an electrically non-conductive material; wherein each antenna is arranged on a respective transmission line through one insulating member arranged at a first end of the antenna and another insulating member arranged at a second end of the antenna . a substrate , set in a space rife of a first medium and made of a second medium; a transmission unit , disposed on the substrate and including a plurality of transmission lines , each said transmission line having a transmission line length that is associated with a first medium operation wavelength that is associated with an operation frequency, and the transmission lines being connected successively; and a plurality of antennas , disposed on the substrate , close to at least some of the transmission lines at positions configured such that the phases of the electromagnetic wave propagating through the corresponding transmission lines at the positions of the antennas are approximate by having a phase difference that is equal to or smaller than 30 degrees, so that each said antenna is able to feed the electromagnetic wave it receives at the operation frequency to corresponding said transmission lines for transmission, and is able to radiate the electromagnetic wave transmitted in corresponding said transmission lines outward at the operation frequency; a plurality of insulating members , wherein the antennas are arranged on the transmission lines , respectively, and the insulating members are disposed between the transmission lines and the antennas , in which each said insulating member is made of an electrically non-conductive material; wherein each antenna is arranged on a respective transmission line through one insulating member arranged at a first end of the antenna and another insulating member arranged at a second end of the antenna . <EOS>