Multi-band and polarization-insensitive electromagnetically-induced transparency based on coupled-resonators in a metamaterial operating at GHz frequencies

Abstract

The analogy of electromagnetically-induced transparency (EIT) has emerged as an intriguing phenomenon in metamaterials research, enabling precise control over electromagnetic wave propagation. In this work, a metamaterial is investigated to achieve polarization-insensitive and multi-band transparency in microwave region. The metamaterial unit-cell consists of three coupled resonators, engineered to exhibit distinct resonance frequencies within the GHz spectrum and their coupling results in transparency windows. The functionality of the metamaterial is validated experimentally, demonstrating dual-band transparency windows at 4.6 and 6.4 GHz. Additionally, under oblique incidence, a third transparency peak arises, and the achieved triple-band EIT peaks can be maintained above 67% up to an incident angle of 60°. Our work contributes a metamaterial platform offering multi-band EIT behavior and polarization insensitivity at GHz frequencies. The proposed structural design leverages coupled-resonator configurations to achieve enhanced control over electromagnetic wave propagation, promising significant advancements in both fundamental research and practical applications. These include advanced signal processing, high-efficiency filters, and sensors operating in GHz communication and radar systems.