Shunt Behavior in RFID UHF Tag According to ISO Standards and Manufacturer Requirements

This paper deals with ultra-high-frequency (UHF) radio-frequency identification (RFID) tag modeling. Examples of electrical models and measurements of backscattering by load modulation in RFID systems can be found in scientific literature in far-field conditions. Load modulation and loading effect are based on the same physical phenomenon: the antenna current is modified by switching the load impedance between two impedances which are frequency dependent. All these models neglect the shunt resistance which can deeply affect the load impedance and may produce failures in the communication system.