Dual-frequency antenna design for RFID application

Abstract

With good read range and fast data rate, UHF Ra- dio Frequency Identi¯cation (RFID) is deployed in the supply chain to identify each item uniquely. However, UHF transmission power is easily absorbed by liquids, such as water. Hence, normally, in a environment with lots of liquid products, an HF RFID system is cho- sen instead. This paper investigates the feasibility in designing a dual-frequency (HF and UHF) RFID an- tenna, with frequency ratio of up to 70, to embrace the bene¯ts o®ered by both the UHF and HF RFID systems. Also, this paper shows that with careful de- sign, a single feed dual-frequency RFID antenna can be achieved. A prototype of the dual-frequency RFID an- tenna is presented in this paper, with valid simulation and measurement results.