Broadband and wide angle microwave absorption with optically transparent metamaterial

Abstract An optically transparent metamaterial for microwave absorber with wide operation angle, polarization insensitivity, broadband and high absorptivity was demonstrated. The metamaterial is composed of planar indium tin oxide (ITO) structures and low-loss glass substrates. By tailoring the reflection response of ITO patterns and the position of arrayed ITO resonators between quartz glass dielectric substrates, more than 90% absorption in the frequency ranges of 8–20 GHz and within a wide angular range from 0° to 60° is achieved. Meanwhile, by employing transparent substrates, including soda-lime glass and quartz glass, good optical transmittance (80%) is obtained. The dielectric loss of quartz glass is lower than other dielectric substrates, which implies that the high absorptivity was achieved mainly due to the contribution of planar ITO metamaterial structure. The reflectivity of proposed MMAs is simulated and measured experimentally. Both of which demonstrate excellent absorption performance of the metamaterial. The optically transparent broadband metamaterials absorber with high absorptivity and polarization insensitivity opens a horizon of potential applications in many fields.