Radio frequency identification (RFID) is a rapidly developing automatic wireless data collection technology with a long history [1]. First multi-bit functional passive UHF RFID systems with a range of several meters appeared in early 1970’s [2] and continued to evolve through 1980’s [3]. Recently, RFID has experienced a tremendous growth due to developments in integrated circuits and radios, and due to
increased interest from retail industry and government [4]. RFID UHF bands vary in different countries and include frequencies between 860 MHz and 960 MHz. Most popular UHF RFID standards are ISO 18000-6B and recently ratified
EPC Gen2. There have been numerous publications on antennas for RFID tags (see, e.g., bibliography in [5]) but only few works have analyzed tags backscattering and radar cross-section (RCS) [6-ช 8]. At the same time, there have been several publications on RCS of linearly and nonlinearly loaded antennas [9-16] not specifically related to RFID. This paper presents a theory and a measurement methodology for determining the RFID tag RCS. It is an extended version of the conference publication [6].