On the basic of fractal theory and folded technique, a miniature antenna for 2.45 GHz Radio Frequency IDentification (RFID) tag applications is designed and analyzed in the present paper. In order to realize the miniaturization of tag antenna, a Hilbert fractal structure is used. Impedance matching between antenna and IC chip is of great importance for improving tag performances. A folded technique is employed to achieve impedance matching flexibly. The value of input impedance of tag antenna can be varied readily only by tuning the high of folded line.