The Isolation Technique Of Antennas With Linear Polarization For RFID Reader

Radio Frequency Identification(RFID) technology is an automatic identification technology using radio waves carrying information stored about the identified object or commands to identify objects via space coupling, such as inductive coupling or electromagnetic wave propagation. It uses non-contact radio frequency two-way communication in order to achieve automatic target recognition and access to relevant data and has many other advantages, such as high accuracy, strong ability to be adapt to the environment, strong anti-interference, quick operation.RFID reader antenna with high isolation is required in order to make label achieve a better identifiy by readers, successful transmit information and reduce the interference of receiving antenna. With the development of dual-polarization, it is taking an important role on the improvement of antenna's isolation, such as the probe fed, double H-slot coupled fed, RP H-slot coupled fed, multi-media fed and mixed fed, etc.This paper details the application of RFID systems and their development prospects at first. Then, based on dual-polarized microstrip antenna research,at first the design of a simple thin orthogonal dual-polarized microstrip antenna fed by probe directly at 915MHz is presented as well as simulation and analysis of its performance; Second, the design of a dual-polarized microstrip antenna fed by L-shaped probe is presented;At last,based on the work before, the final design of a improved orthogonal dual-polarized microstrip antenna fed by L-probe is reached.Further, eleetromagnetic simulation is proeessed by using HFSS, and meanwhile the impact of the key dimensions for the antennas to the performance are summarized to be adapt to RFID reader.In addtion, the paper also relates to the basis parameters introduction of antena as well as the description of antenna measurement.