Microfluidic Metasurface with Constant Absorption Efficiency Throughout the Ku Band

Metasurfaces with designable electromagnetic parameters are ideal candidates for broadband and tunable microwave absorbers. Water-based metasurface microwave absorbers have been demonstrated to exhibit ultra-broadband and near-unity absorption. However, a broadband microwave absorber with constant and designable efficiencies remains a challenge due to stringent impedance-matching conditions over a large frequency region. In this work, a design paradigm of microfluidic metasurface absorbers is proposed to regulate absorption efficiency over a wide frequency range. As an example, microfluidic metasurface absorbers are demonstrated with constant absorption efficiency over the Ku band, which is designable from 61.8% to 99.9%. The broadband metasurface absorbers have the advantages of easy fabrication, low cost, and optical transparency, making them highly promising for applications in fields like electromagnetic shielding, active camouflage, electromagnetic pollution control, and wireless communications. A broadband all-dielectric microfluidic metasurface absorber with adjustable absorption efficiency is designed and fabricated. In the Ku band, the absorption efficiency of the microfluidic metasurface absorber can be tuned from 61.8% to 99.9% by designing the structure parameters of the metasurface. Simultaneously, the absorption value remains constant across a wide frequency range. image