In this paper, a new type of terahertz (THz) metamaterial (MM) modulator has been presented with bifunctional properties based on vanadium dioxide (VO₂). The design consists of a VO₂ resonator, polyimide substrate, frequency selective surface (FSS) layer, and VO₂ film. Based on the metal-insulator transition (MIT) of VO₂, this structure integrated with VO₂ material can achieve the dynamic modulation on both transmission and reflection waves at 2.5 THz by varying the electrical conductivity value of VO₂. Meanwhile, it also exhibits adjustable absorption performance across the whole band from 0.5–7 THz. At the lower conductivity ($\sigma$ = 25 S/m), this structure can act as a bandpass FSS, and, at the high conductivity ($\sigma$ = 2 × 10⁵ S/m), it behaves like a wideband absorber covering 2.52–6.06 THz with absorption A > 0.9, which realizes asymmetric transmission. The surface electric field distributions are illustrated to provide some insight into the physical mechanism of dynamic modulation. From the simulated results, it can be observed that this design has the capability of controlling tunable manipulation on both transmission/reflection responses at a wide frequency band. This proposed design may pave a novel pathway towards thermal imaging, terahertz detection, active modulators, etc.

Flexible metamaterial absorber manufactured with layer-by-layer screen overprinting methodology has been theoretically and experimentally studied in this wok. The effective absorption of the absorber is in X band (8.3GHz to 10.9GHz) and its working principle have been verified and analyzed. Benefiting from the elimination of the parasitic effect brought by package-free and direct-contacted planar resistors, high agreement between simulations and measurements has been achieved. The working frequency band can be easily tuned by replacing different supporting and covering layers, to fit various purposes. Mechanical flexibility of the absorber enables its conformal coverage to aiming objects for RCS reduction, and is experimentally confirmed on metallic cylinders with different diameters. It has been clearly demonstrated that the high-efficiency and cost-effective automatic screen-overprinting method matches perfectly for large-size flexible absorber and its industrial applications.

The design of an optically transparent and flexible metamaterial absorber was presented and fabricated. For this purpose, we use two different patterned silver nanowire films separated by the space layer, forming a transparent sandwiched structure with an ultrathin thickness. By analyzing the equivalent circuit model and distribution of electric field and current, the absorption physical mechanism has been theoretically investigated. The results show that the structure can achieve above 0.8 absorptions from 6 GHz to 18 GHz, and at the same time, this absorber also can obtain wide-angle property. The optical transmittance of the fabricated absorber exceeds 82% in the visible band. The results demonstrate that transparency and flexibility are the additional benefits that make the proposed absorber suitable for various potential applications.