Wireless Voltage Regulation for Passive Transponders Using an IF to Communicate

This paper presents a novel architecture for wireless communication systems made up of a base station and a remotely powered transponder. The architecture enables the base station to perform wireless voltage regulation (WVR) of the rectifier´s output voltage in the transponder. This new regulation technique can be embedded in any system, provided that the passive transponder uses an IF to transmit data to the base station. The technique relies on a large scale, wireless feedback loop that includes the base station, and the transponder. The overall power efficiency of the system is improved compared to conventional voltage regulation technique. A small-signal model is derived to gain some insight on the dynamics and on the stability of the feedback loop. Measurements were made on an actual system operating in far field at 866.6 MHz. They demonstrate the efficiency improvement related to the use of WVR. The validity of the small-signal model is discussed according to the measurement results.