The effect of lossy dielectric objects on a UHF RFID meander line antenna

Meander line antennas placed on various objects suffer a shift in resonant frequency. Numerical modeling demonstrated that the frequency increases with wire diameter and object conductivity, and decreases with increasing permittivity. This contrasts with a linear dipole where an increase in wire diameter results in a decrease in resonant frequency. A 4% bandwidth is sufficient for conductivity (σ) values up to 0.01 S/m and small changes in permittivity. This has implications for RFID antennas designed for placement on a wide variety of materials.