| The cost of RFID tags is the main reason for restricting its widespread application. Chipless tags can greatly reduce the cost. The existing chipless tags about anti metal surface are still relatively poor. This paper studies chipless tags about anti-metal surface.Firstly, according to the FSS and HIS characteristics, we designed three tags based on multiresonant HIS, including Patch-ring type, Slot-half ring type, Patch-cross type. We analyze each of these three types of tags from feasibility, the angle of incidence, the angle of polarization. Then compared and concluded that the Patch-ring structure is polarization independent, compact and stable, realizing 10-bit data encoding, or even higher. These can be used on metallic objects. The study provides a new way of thinking about chipless tags.Secondly, we analyze C resonator unit structure which can be printable. These tags can’t be applied to the metal surface, and sensitive to the polarization angle. By analyzing its RCS, we improve the frequency encoding method commonly used in the past. We designed the structure by using hybrid coding and frequency shift coding. At last, we briefly summarize different encoding methods.Finally, due to the influence of the reflected wave from the metal platform, the depth of resonance with Co-polarization RCS will be damaged. So we study a new coding method, cross polarization coding, which is based on cross-polarization component of RCS. This coding method can resist the influence of the metal platform. Using SEM and MPM to extract the poles of these tags we designed, in order to achieve detection and identification tag structure. |
