Abstract—Thisletterproposesaminiatureradiofrequencyidentification (RFID) tag antenna design for metallic objects application. The antenna structure consists of two rectangular patches electrically connected throughvias to the ground planeand anonconnectedinterconductivelayertoformanRFIDtagantennathat 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 antennaimpedancecanbeobtainedwithasmall-sizeRFIDtagantenna. 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 mm. Simulation and measurement resultsoftheproposedRFIDtagantennaarealsopresentedinthis letter.