Multifunctional Reference Cells for Multistandard RFID Transponders

This paper at first illustrates implementation aspects and measurement results of a subcomponent for a multistandard RF identification (RFID) transponder. It is intended to be a common reference cell, both for basic UHF requirements and advanced application fields like local positioning and wireless sensing. Different single circuit topologies shown in previous studies or literature and their applicability for that RFID system are evaluated. After that, measurement results of two final circuit configurations, including a newly designed RC oscillator with metal-metal capacitors, are discussed and compared. Layout aspects for reducing the process variations and low power consumption are demonstrated. Simulation results show border conditions for the power supply of the transponder on chip level. Moreover, distance measurements with our first complete transponder compliant to the electronic product code protocol are shown. It includes the newly presented reference cells and other necessary transponder components. All chips are designed based on a 0.13-μm CMOS technology.