RFID tag design approach based on chip multi states impedance

The knowledge of binary RFID chip impedance is exploited for tag antenna design and applied to the NXP G2XL chip. The impedance states are measured with respect to frequency and input power on the chip. An analytical model is used to predict the optimal antenna impedance that corresponds to the maximum backscattered power from the tag. Automated antenna design tool with original shape generation is used to get a tag with optimized modulation efficiency in the UHF RFID frequency band from 860 MHz to 960 MHz. The optimized tag is designed to present good performance on two different environments: free space and above dielectric material. Measurement done in an anechoic chamber shows good performance comparing to the commercial tag NXP FFL 95-8 designed by NXP.