Improved radio-over-fiber-based distributed antenna system with antenna diversity for passive UHF RFID

Passive radio frequency identification (RFID) is an automatic identification technology which has been widely used in the field of the Internet of Things (IOT). In this paper, a RoF-based DAS RFID system with antenna diversity is proposed and experimentally demonstrated. The dynamic sensitivity of uplink is specially considered and photonics lantern (PL) is used to reduce the loss of signal combination. In order to verify the ability of the proposed system, we conduct a series of experiments depends on different number of tags and different transmitting power levels with the proposed system and RF switchable system in a typical lab environment. The experimental results show that the new approach improve the tag detection speed by almost 15% over a sparse environment and 10% over a dense environment respectively, compared with a RF switchable RoF DAS RFID system. The new approach is more accurate and faster than the RF switchable system with the same reader transmission power.