High gain design of small axial mode helical antenna over a cylindrical cavity for RFID applications

Abstract

Increasing the range of Radio Frequency Identification (RFID) system without parasitic tag reading is a challenging problem. A small helix antenna with high gain for RFID reader covering UHF band of 860MHz-960MHz is presented in this article. We show that using a cylindrical shaped ground plane can increase the gain of helix antennas in several UHF RFID frequency bands. The cylindrical ground plane geometry has been simulated and optimized with HFSS software. The optimal structure has a total size of 680×680×300mm3 and exhibits a constant realized gain around 13.8dBic over a large bandwidth with a good axial ratio (less than 2dB).