Linearly-tapered RFID tag antenna with 40% material reduction for ultra-low-cost applications

The development of RFID technology are requiring high performance and low cost tag antennas than ever before. To meet these demands, linear tapering technique is firstly proposed in the design of planar tag antennas. With this strategy, the current distribution along antenna arms is effectively assigned by varying the antenna line width. Compared with conventional ones, the tapered antennas can reduce the material cost by over 40% not only for PCB (Printed Circuit Board) processed, but also for ink-jet printing produced dipole and meander line antennas, while they still maintain comparable performance. With an identical volume of conducting material, the tapered antennas can achieve better radiation performance than non-tapered ones on antenna gains and radiation efficiencies. The method has been successfully verified by applying it onto 869 MHz and 2.45 GHz antennas. The influence of the tapering technique on antenna bandwidth is also investigated.