Measurements of UWB Antennas Backscattering Characteristics for RFID Systems

A measurement technique, which is carried out in indoor non-anechoic-chamber environment and can be employed to extract the backscattering characteristics of ultra-wideband (UWB) antennas for radio frequency identification (RFID) systems, is developed and presented in this paper. To validate the measurement technique, a type of UWB antenna, i.e., printed circular-disc monopole antenna (PCDMA), is simulated, fabricated, and measured. Backscattering characteristics of the PCDMA with three different kinds of terminations (i.e., open-circuit, short-circuit, and matched-load), including radar cross section (RCS) and UWB impulse response, are then extracted by the measurement technique. The measured results are theoretically verified by using the finite-difference time-domain (FDTD) method with Berenger´s perfectly matched layer absorbing boundary condition (PML-ABC).