A low-power multi-standard frontend for wireless sensor networks

This paper presents a low-power multi-standard frontend for passive wireless RFID based sensor networks. The CMOS only frontend is implemented in a 0.13 μm CMOS technology. It includes a highly efficient rectifier for UHF and HF to supply the digital logic, the integrated sensor interface and the necessary auxiliary circuits like a low-power voltage/current reference and the local oscillator. Furthermore the complete sensor enhanced RFID transponder is able to communicate with a standard EPC HF and UHF RFID reader. The DC power consumption of the analog frontend components is about 3 μA. The measured overall RF-to-DC power conversion efficiency of the complete analog frontend for a DC output power of 10 μW is about 17% at -11 dBm RF input power for UHF. To the authors´ knowledge, this is the highest UHF efficiency achieved by a multi-standard sensor tag. The efficiency of the HF frontend at -4 dBm RF input power and 1 V V_DD is about 10%. The maximum efficiency of the frontend is about 17% at HF.