Performance of RFID tags with multiple RF ports

In this paper, we concentrate on analysis of read range and orientation sensitivity for RFID tags with multiple RF ports and present experimental data for one- and two-port tags. Passive radio frequency identification (RFID) is an automatic wireless data collection technology where RFID reader transmits a modulated RF signal to the RFID tag consisting of an antenna and an integrated circuit chip. The chip receives power from the antenna and responds by varying its input impedance and thus modulating the backscattered signal with data. Important RFID tag characteristics are maximum range and orientation sensitivity. These characteristics can be improved in the RFID tags with multiple RF ports where each port can be connected to a different antenna. The signals from those ports can be combined to increase maximum tag range and to make it less sensitive to orientation.