Dual-band RFID tag antenna using coplanar inverted-F/L structure

In this paper, we introduced a new antenna topology for RFID tag that could be implemented simultaneously to support the UHF band of Europe (866 MHz-868 MHz), the UHF band of North America (902 MHz-928 MHz), and the microwave band for ISM (2.4 GHz to 2.45 GHz). The antenna proposed herein was composed of a planar inverted-F and a parasitic inverted-L, both of which formed a small, simple and cost effective architecture which was especially tailored for the standard tag size as a credit card with of 85 mm in length and 54 mm in width. The antenna was fabricated on the polyethylene substrate (ε
_r
=2.35, tan δ =0.002), providing the return loss less than -10 dB over all bands of interest. Besides, study in this paper also referred to the impedance characteristics and the radiation patterns, revealing good impedance consistency and Omni-directional far field patterns over all the concerned frequency bands.