A Miniaturized Tag Antenna for UHF RFID Metallic Objects

Abstract

A very simple and compact metal-mountable structure is proposed as a tag antenna in UHF RFID systems. Two shorting vias are adopted to connect the ground plane and to reduce the tag size. Some folded meander strips are introduced to further miniaturize the tag size, achieving a compact tag antenna size of 10×30×1.5 mm3, The input impedance of this tag antenna can be easily matched to the complex conjugate of a chip's impedance by using a double T-match network. The measured maximum read distance can reach 4.5 m at the resonant frequency of 912 MHz.