Theory and Measurement of Delta RCS for RFID Tag on Various Materials

Delta radar cross section (RCS) is an important parameter for the performance of passive UHF RFID tag. It determines the bit error rate (BER) at reader side when the signal which backscattered from the tag is polluted by kinds of noises. But the measurement of delta RCS can't be obtained directly and thus, indirect method must be considered. The paper introduces our measurment methodology for tag's delta RCS, including the National Instruments (NI) RF modular and the LabVIEW based signal analysis programe. This paper also has analyzed two main factors which influence delta RCS seriously, and gotten some test results when tags were attached on various material objects for different transmitted power.