Design of RFID antenna

Abstract

In this report, the design of an inductively-coupled feed for an RFID tag antenna is modified to realize a platform-tolerant characteristic. Based on the previous design, a new feeding network is used for the tag antenna as a larger inductance can be produced to compensate a larger chip capacitance. In the new feed, parts of the feed line are connected directly to the radiating element to realize a platform-tolerant RFID tag antenna, which comprises a microstrip patch. Since there is a ground plane underneath the patch and the feedline, the performance of the tag is essentially independent of the surface upon which the tag is mounted. This desirable feature of the tag is confirmed by the measured results presented herein. In addition, the RFID tag antenna is designed by using FR-4 substrate in order to reduce the production cost. Hence, the method of measuring FR-4 loss tangent and dielectric constant is introduced.