New properties of UHF RFID transponders on metal with microstrip antennas

RFID technology based on UHF frequency has become the most economical identification method, when pallet- size items are being identified full-automatically, with no active human assistance. When goods are travelling long distances, "smart labels" used in disposable packaging are a good choice. In Europe the amount of returnable transport items (RTI) used in supply chain is significant. Typically the RTI's like containers, trolleys and dolly's are metallic. Even non-metallic RTI's like pallets, boxes and crates often contain metallic objects leading to a need of an RFID transponder that works well on metallic objects.