Fabrication and assembly of a novel high-efficiency UHF RFID tag on flexible LCP substrate

Abstract

In this paper, design, fabrication, assembly and testing of unique high read-range high-efficiency (95%) radio frequency identification (RFID) antenna for the 915 MHZ UHF band are discussed. The exceptional characteristics of the RFID are investigated in terms of antenna-IC matching and radiation efficiency. The 915 MHz passive tag is a 3" times 3" omnidirectional tag and yielded a read range of 31 feet compared to a 4" times 4" leading commercial design of 26 feet tested range in lab. This tag also possesses higher read power range (-7dBm to 30 dBm) than the leading commercial design (-5dBm to 30 dBm). The proposed RFID antenna was fabricated on 50 micron thick liquid crystal polymer (LCP) substrate and the read range of the proposed RFID tags was experimentally verified. A large format LCP sheet (300 mm times 300 mm) was used for antenna fabrication and the assembly of the IC was done using low temperature lead free solder alloys that are compatible with the heat distortion temperature of the LCP