Research On Impedance Prediction Of Radio Frequency Identification Tag Antenna With Folded Dipole Based On Polynomial

In the process of solving the problem of slow impedance calculation speed in the design of Radio Frequency IDentification (RFID) tag antenna, a method of impedance prediction based on polynomial for folded dipole RFID tag antenna is proposed in view of the complex impedance coupling. Firstly, impedance transformation based on antenna size and linearization assumption are used to establish model hypothesis. Then the data are collected from the antenna structure and the correlation analysis and regression fitting are carried out to verify the validity of the hypothesis. Finally, the accuracy, efficiency and universality of the impedance prediction method compared with computer simulation are verified by experiments. The experimental results show that the predicted impedance can greatly shorten the calculation time while maintaining high prediction accuracy when the proposed method replace computer to calculate the impedance of the folded dipole RFID tag antenna, and the method is still applicable to the RFID tag antenna with different bending times in the frequency band used in China.