Delta RCS of UHF RFID taking into account the shunt resistance in the tag model

This paper deals with UHF RFID tag modeling. Recent electrical models present theory and measurements of backscattering by load modulation in RFID systems. These models fit with measurements in far field conditions. Load modulation and loading effect are based on the same physical phenomenon: the antenna current is modified by the load impedance. In far field, we can assume that the load modulation is made by switching between two impedances which are frequency dependent. These models neglect the shunt resistance which can deeply affect the load impedance and may produce failures in the communication system.