A compact RF/analog front-end for microwave RFID transponders

This paper deals with the design and implementation of a flexible, very compact RF Analog Front-End (AFE) for RFID transponders working in the UHF and microwave frequency ranges. The AFE is part of a complex SOC providing long-range RFID-based communications in combination with on-chip sensors for temperature and humidity as well as other mixed-signal modules like ADCs, DACs and signal conditioning circuitry. The RFID-based AFE is one important piece of a modular platform technology employed in the quick implementation of customized applications. The entire front-end comprises an area of 0.3 sq. mm and delivers over 100W of power at a readout distance of 3m with a 3 dBi dipole antenna an a RFID-reader nominally radiating 3W at 868 MHz.