Antenna design for RFID system

Abstract

In recent years, we have found a great impact of Radio frequency identification (RFID) technologies in our daily life. There is a great demand on directional radiating antennas to the readers in RFID systems in the market. In my project, an innovative design of accordion helical antenna is presented. This type of antennas achieved a new feature of circularly polarization with tilted directional radiation that can be operated in the radio frequency of 860MHz to 930MHz. The 3dB axial ratio bandwidth of 10turn accordion helix is found to be around 8% when bending angle is 22.5°. It achieves a comparable low profile characteristic with the traditional helical antenna as the pitch angle of helix is reduced from the optimum 12°[1] to 2°. The half power beamwidth is around 45°65 ° when bending angle is increased from 5° to 30° with 10 turns. The antenna has potential application in RFID systems.