Design of UHF Semi-active Tag Antenna

Ultra-high frequence radio frequence identification tag adopts the way of actively transmitting electromagnetic waves by read-write antenna and passively backscattering by tag antenna, which has the characteristics of high communication data rate and long reading distance. It can support the identification of multiple targets and moving targets at the same time. According to the complexity of structure and application scope, it can be divided into three categories: passive tags, semiactive tags and active tags. Semi-active tags have attracted more and more attention as a new field between passive tags and active tags. Because they carry batteries, the problem of energy supply required for chip operation is solved, which greatly reduces the requirements of tags on the power intensity of input RF signals. Compared with passive tags, the read-write distance and recognition efficiency of tags are greatly improved. According to the latest development trend in Ultra-high frequence(UHF) identification field, a semi-active tag with power supply circuit system with wake-up circuit and amplification circuit is designed in this paper, which not only realizes long-distance effective reading in UHF(915MHz) band, but also greatly reduces standby power consumption.