Effects of size and shape of metallic objects on performance of passive radio frequency identification

Passive ultra high frequency (UHF) spectrum radio frequency identification (RFID) systems have numerous applications. Continuous research and development of RFID systems is carried out to study solutions for different challenging cases of identification. Metallic objects set challenges for identification due to the behavior of electromagnetic waves on conductive boundaries. Therefore, novel tag designs have been developed for identification of metallic objects. This article presents a performance comparison of two different metal-mountable tag antennas, which are printed inverted-F antenna (IFA) and microstrip patch antenna with photonic band gap (PBG) ground plane and with regular ground plane. The effects of size and shape of metallic objects on tag antenna performance are studied with read range measurements and compared between the tag antenna types.