A Meander Line UHF RFID Reader Antenna for Near-field Applications
A novel ultrahigh frequency radio frequency identification reader antenna based on electromagnetic coupling between two open-ended microstrip (MS) meander lines for near-field applications is investigated in this paper. The corresponding currents flowing along the two MS meander lines are reversed in phase with approximately identical amplitudes. Meander-line units are introduced to achieve a uniform distribution of strong magnetic and electric fields. The performance of an antenna prototype comprised of six pairs of meander lines is analyzed. The proposed antenna simultaneously exhibits a uniform magnetic field distribution with a reading region of 480 mm $\times200$ mm $\times20$ mm and a uniform linear electric field distribution with a reading region of 480 mm $\times420$ mm $\times300$ mm. The proposed antenna exhibits a low far-field gain, and has a bandwidth from 914 to 929 MHz. Both simulated and measured results have shown a good performance of the antenna.