On the read zone analysis of radio frequency identification systems with transponders oriented in arbitrary directions

One of the most important characteristics of a Radio Frequency IDentification (RFID) system is its "read zone", which is defined as the volume inside which the base station can communicate with the transponders (or, tags). This paper presents a systematic approach to analyzing the read zone of an RFID system where the base station antennas are a pair of switchable circularly polarized antennas and the transponder antennas are linearly-polarized and oriented in arbitrary directions.