In order to reduce cost of tags in traditional RFID system and increase coding capacity without significantly increasing label area

a single surface compact and completely printed chipless tag is presented based on the natural resonance of conductor. The tag is composed of multiple equilateral triangle slot ring resonators nest. By adding or missing triangular slot with different lengths on the conductive material

it can effectively encode information and get various coded tag. The back scattering signal of the tag is obtained by using the plane electromagnetic wave to illuminate the tag

and then the coded information is extracted by using the radar cross section（ RCS）. The RCS can be increased by placing 4 same ID tags on the substrate symmetrically. The coding capacity of 12 bit can be achieved on the 24 mm × 22 mm Taconic TLX-0 substrate. The feasibility of the tag structure is verified by simulation

and the reading of the tag data is independent of the polarization direction of the incident wave.