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This letter proposes a miniature radio frequency identification (RFID) tag antenna design for metallic objects application. The antenna structure consists of two rectangular patches electrically connected through vias to the ground plane and a nonconnected interconductive layer to form an RFID tag antenna that is suitable for mounting on metallic objects. The miniature design is achieved by inserting a conductive layer into the antenna structure to increase the capacitive reactance of the antenna. This causes the self-resonant frequency of the proposed antenna to approach low frequency; therefore, the high imaginary part of the antenna impedance can be obtained with a small-size RFID tag antenna. The experimental tests show that the maximum read range of RFID tag placed on a metallic object is about 1.5 m, and the overall size is 32 times 18 times 3.2 mm3. Simulation and measurement results of the proposed RFID tag antenna are also presented in this letter.