Wireless Power Transfer for RFID Systems

This chapter discusses the context and some historical facts for the development of wireless systems and their first exploitation for communication and power transmission. Backscatter technique is becoming a topic of great interest, in particular for the implementation of the rapidly emergent internet of things. Voltage at a transponder coil in the range 1–100 MHz, for constant current i1. Comparison between resonant and non-resonant coupling. Modulating the perturbation impedance allows the tag to generate specific responses to the reader. It consists in controlling the load impedance. A simple frequency divider can be used to generate different subcarriers from the communication frequency generated by the reader. The patch antenna is used at the reader side. The major advantage is the easy method to generate circular polarization. Re-radiation process of antennas. When an antenna detects a signal, it generates a current on its metallic part, which turns in new radiation signal.