Improvement of radiation efficiency of radio frequency identification tag antenna for metallic objects printed on lossy substrate

A new antenna design method is proposed for radio frequency identification tags on metallic surfaces, using a low-cost, high-loss substrate such as FR4. The proposed method significantly reduces the dielectric loss of the substrate and so improves the radiation efficiency of the tag antenna by almost double compared with a conventional planar inverted-F antenna. The equivalent circuit model of the antenna designed is established and its characteristics analysed systematically. The superiority of the proposed design method is demonstrated and verified by fabricating a prototype antenna and presenting experimental results of the measurements obtained.