A novel antenna achieving null-less magnetic field distribution for near-field UHF RFID

In this paper, an antenna which can generate large, strong, and uniform magnetic field distribution is proposed for the near field magnetic coupling UHF RFID system. The antenna is composed of two elements and a feeding network. By feeding the two elements at different phases, their dead zones can be compensated by each other. Consequently, a uniform magnetic field distribution is achieved, which will be helpful in designing item level RFID system. And the perimeter of the interrogation zone is up to 5.4λ at 920MHz.