UHF RFID Reader Antenna Design Technology Research

Radio Frequency Identification technology (Radio Frequency Identification, RFID) is a non-contact automatic Identification technology, and bar code and other Identification way in, this technique has high accuracy, speed, distance, environmental adaptation ability etc, in recent years development speed is very fast. And reader antenna of the RFID system is the key part of the performance of antenna directly decide the system validity and reliability, so its research and design become the hot spot in recent years. This paper is mainly aimed at the reader antenna made a detailed research and design.This paper first according to the theoretical analysis, introduces the basic principle of RFID technology, mainly introduces the RFID reader and microstrip antenna as RFID reader antenna has the advantage. Then a detailed study of the microstrip antenna related theory, including the definition of microstrip antenna, the typical structure, radiation principle, size calculation and analysis method, etc.Then, based on the theoretical analysis about microstrip antenna, on the basis of the first design a kind of ultra-high frequency coaxial feed rectangular RFID reader antenna, and using HFSS software simulation calculation, get the initial antenna size of some performance parameters, the center resonance frequency and requirements of the2.45GHz slightly differ from value, and then to the optimization of the antenna, by changing the feeding point coordinate values, obtained in the process of change, impedance and return loss change relations, so as to find the best feeding point, and make other performance meet the design requirements.Finally, on the basis of the previous chapter designed a kind of double frequency coaxial feed rectangular microstrip antenna, the resonant frequency were1.9GHz and2.45GHz, realize the method is by changing the feeding point position, will feed point in front design axis up to the diagonal, get can also produce two kind of resonance frequency of the antenna, then the documentary frequency antenna similar analysis, simulation, optimization method to find the best feeding point, and at the same time make other performance parameters meet the requirements.