Research And Design Of RFID Reader Antenna

With the development of science and technology,the RFID has been applied more and more widely,and the RFID technology presents a trend of rapid development.Antennas play an important role in RFID system,which determine the realization of the system's function of non-contact identification.The reader antenna determines the working frequency and the performance of the whole system.Therefore,it has a great significance to research the reader antenna.The LF and HF reader antennas show short write distances,which commonly be used in the near field conditions.For the far-field applications,usually require the UHF and microwave bands reader antenna.The main work of this article is to study and design UHF and microwave bands reader antennas,and the article consists of the following three parts:The first part,introduce the background significance,applications and research status of the issue briefly.Then summarize the composition and working principle of the RFID system,focusing on the RFID antenna system.Since,the designed antennas in this paper are all microstrip antennas,the radiation theory and the main parameters of the microstrip antennas are analyzed.Finally,this part proposes the main requirements of the RFID reader antenna design and the plans of the reader antenna design.The second part,design two multi-band reader antennas,which allows a reader to read different bands tags,and the use of the reader become more flexible.The first antenna is a dual-band reader antenna,which can operate at 2.45 GHz and 5.8GHz.Its novel and effective structure provides a guideline for the second antenna design.The second antenna designed in this part is a tri-band reader antenna.This antenna can greatly improve the efficiency and application scope of the reader,which make up for the shortcomings of the several tri-band reader antennas had been proposed now.It can cover the UHF and two microwave bands(2.45 GHz and 5.8GHz band).More importantly,the UHF band of this antenna can cover all countries' UHF bands of RFID system,which is a characteristic that the several existing tri-band reader antennas do not have.Thus,this antenna not only can be used to read the two microwave bands electronic tags,when the UHF tags attached to the objects coming from different countries,which have different UHF band,this antenna but also can read different countries' UHF tags,which makes the reader has a broader range of applications.The third part,in order to further improve the utilization of the reader,make the reader read electronic tags from different directions,and avoid the phenomenon of polarization mismatch,this part propose two circularly polarized reader antennas.By using a single feed point and introducing the perturbation methods to achieve circular polarization antennas.The first circularly polarized antenna designed in this part can operate at 2.45 GHz band,which achieve a good characteristic of circular polarization.To make a reader antenna not only have circular polarization characteristic,but also can read different bands electronic tags,this part designs the second antenna.This antenna can cover the 2.45 GHz and 5.8GHz bands,and it has good performance,which can improve the utilization and flexibility of the reader to a greater extent.