Design of multistage rectifiers with low-cost impedance matching for passive RFID tags

The paper presents analysis of the input impedance, as well as the input capacitance and output resistance of diode doublers and multistage rectifiers. Tradeoffs between device sizes and the number of rectification stages are presented with an emphasis on low cost impedance matching. As a result, it is possible to achieve higher efficiency in RF to DC conversion with low cost impedance matching by using just a strap inductor between the antenna and the rectifier IC. Four diode doublers and three multistage rectifiers have been designed and fabricated using a 0.13mum CMOS process with EEPROM. Measurement results are in agreement with the analysis