Fractal-Shaped Metamaterial Absorbers for Multireflections Mitigation in the UHF Band

A Minkowski fractal geometry is proposed in this letter as miniaturized absorber cell suitable for multipath phenomena mitigation within the European RFID UHF band. The proposed structure is analyzed through the combined use of an equivalent transmission line model and method-of-moments-based full-wave simulations. Very high miniaturization capabilities (about 50% with respect to standard configurations) are demonstrated for an 868 MHz absorber unit cell, characterized by an absorptivity more than 99%, a good angular stability, and a very thin substrate (≤λ0/100). The proposed configuration is appealing for designing compact absorbers useful for multipath reduction in wireless systems operating on restricted indoor environments.