Design and performance analysis of a planar antenna for near-field UHF-RFID desktop readers

A near-field UHF (865-928MHz) RFID desktop reader antenna is designed by means of a traveling wave antenna. Since the detection of a tagged item in an arbitrary position and orientation is desirable, a meandered coplanar waveguide (CPW) line is properly designed, getting an homogeneous magnetic field amplitude. The main parameters of the RFID reader antenna (reflection coefficient, gain, effective isotropic field factor) are presented and discussed. Furthermore, the simulated and measured H-field distribution are compared, resulting in a good agreement. Finally, the overall RFID system performance is evaluated in terms of tag detection, considering short-range and long-range commercial RFID tags.