Active frequency selective surface for time-domain UWB RFID applications

An ultra-wideband radio identification (RFID) system based on modulating an actively controlled frequency selective surface (FSS) is proposed. The tag modulates its backscattered time-domain response to an input ultra-wide band pulse. This is achieved by changing the radar cross section (RCS) of the FSS which is loaded with switching PIN diodes. The operation theory of the system is described. A low-power ultra-wideband radar is used as the reader. Experimental results of a proof of concept tag are presented.