Development of 900MHz band one-sided directional antenna on flexible substrate

In this paper, we designed a planar one-sided directional slot antenna on flexible substrate for UHF Radio Frequency Identification (RFID). Our proposed planar antenna has the impedance matching circuit composed of coplanar waveguide (CPW) transmission line and interdigital gap, and a top metal layer and a bottom metal layer (floating ground). In order to realize the one-sided directional properties, the length of the top metal layer is adjusted, and at that time, the bottom metal layer is adjusted to the length that doesn´t resonate. The final antenna size for the UHF band RFID applications is 67 mm × 61 mm × 1.3mm. In order to observe the radiation characteristics of the proposed antenna on the flexible substrate, we fabricated the one-sided directional slot antenna using dielectric substrate that can be bent a little, and results of measurements are compared with that of simulation.