Retrodirective Harmonic Tag Using Van-Atta Array Consisting of Dualband Unidirectional Antennas

We propose a retrodirective harmonic tag using a planar unidirectional dual-frequency antenna in a Van-Atta array. In applying the Van-Atta array to harmonic tags, we address the constraints on element spacing. In the effectiveness evaluation, we demonstrate both computationally and experimentally that the proposed design offers advantages in terms of gain and coverage range compared to a Van-Atta array using single-frequency antennas and an array without retrodirective characteristics.