Design of UHF RFID Passive Tag Antenna Pasted on a Large Metal Structure

摘要

In this paper we present a new design of patch-type antenna using a loop circuit located inside the antenna structure to excite the antenna, which has potential to resolve the problem arising from the situation when the antenna is pasted on a large metal ground. The problem of large metal structures to the RFID tag antenna arises because most of the RFID uses electrical dipole-type antennas. In this case, the presence of large metal structure will short the antenna and reduce the radiation field strength. The proposed antenna structure is a magnetic type. The proposed design concept intends to optimize the field distribution within the substrate between the patch and ground, and therefore may reduce significantly the antenna size. Experimental study showed that the antenna may be used to enhance the reading range to be more than 3 meters.