Development of Metal-Compatible Dipole Antenna for RFID

Abstract

We developed a metal-compatible RFID dipole antenna. The antenna consists of three layers, including the top metal, dielectric substrate, and bottom metal, with the top metal and bottom metal of the dipole antenna shorted at the side edges of the antenna. In order to accurately measure the gain and reflection coefficient (|S11|) of the antenna in the desired frequency band, an impedance matching circuit was created using an open stub around the feeding section of the antenna. The simulation and measurement results of the |S11| and antenna’s realized gain are presented in this paper. The measured |S11| has similar characteristics to the design results at around 915–940 MHz. The size of the proposed antenna is 70 mm × 50 mm × 1.636 mm. In addition, the antenna can be bent at 0, 3, or 5 divisions to fit curved metal objects such as lithium-ion batteries (LIBs). This antenna structure is a fundamental area of study for future application to flexible substrates. Conductive adhesive tape (copper tape) was used to connect each section. The surface of the copper tape was fixed with adhesive to prevent it from peeling off. In the simulation and measurement, it was confirmed that our proposed antenna could operate around the desired frequency band. In the future, we plan to install an IC chip in the antenna input section and work towards implementing it in society.