Liquid crystal-based reflective dual-band sub-terahertz phase shifter.

A terahertz (THz) phase shifter based on a liquid crystal and a single-layer metasurface with a shared aperture for dual-band antennas is proposed. The device achieves phase shifts exceeding 180° in dual-frequency bands, with simulations indicating 236.8-248.

A tunable broadband terahertz MoS absorber using series-parallel hybrid network design.

A method for designing a broadband absorber using a series-parallel hybrid network is proposed. The performance of the broadband absorber is improved by using frequency-selective surface patterns based on a series-parallel hybrid equivalent circuit. The results indicate that the tunable single-layered terahertz MoS absorber has excellent broadband characteristics.

Electrically controllable broadband reflective linear cross-polarization conversion based on liquid crystals.

This paper presents an electrically controllable reflective broadband linear polarization (LP) converter based on liquid crystals (LCs) for cross-polarization conversion (CPC) in the terahertz frequency range. The proposed structure achieves a high polarization conversion ratio (PCR) exceeding 0.9 within the frequency range of 236.

Manipulation of sub-terahertz waves using digital coding metasurfaces based on liquid crystals.

This paper presents a novel sub-terahertz liquid crystal (LC) phase shifter based on digital coding metasurfaces. The proposed structure consists of metal gratings and resonant structures. They are both immersed in LC.

Wideband linear cross-polarization conversion with 3D metamaterial configuration.

In this Letter, a broadband and wide-angle linear polarization (LP) converter based on a 3D resonator for cross-polarization conversion (CPC) is presented. The designed structure performs a CPC with a polarization conversion ratio (PCR) of more than 90% in the frequency range 16.32 to 34.

Electrically active control of terahertz waves in a hybrid metasurface-grating structure with a liquid crystal.

A reflective terahertz phase shifter for wide-range dynamic and continuous phase modulation is proposed. By injecting a tunable liquid crystal between the slotted metasurface and the grating microstructure, the phases of reflected waves can be modulated with different electrically driven methods. Numerical simulations show that the proposed terahertz phase shifter has a phase difference of more than 360° between unbiased and biased states.

Rapid terahertz wave manipulation in a liquid-crystal-integrated metasurface structure.

A terahertz phase shifter based on liquid-crystal-integrated metasurface is proposed, which contains a three-slotted array structure and comb grating. The orientation of the liquid crystal molecules can be completely controlled by the direction of the electric field. From the acquired experimental results, it was demonstrated that the phase shift exceeds 300° in the range of 378.

Liquid crystal-based wide-angle metasurface absorber with large frequency tunability and low voltage.

A tunable metasurface absorber (MA) based on polymer network liquid crystal is introduced in this paper. Despite the well-designed unit cell patterns, the proposed MA can achieve both large frequency tunability and wide-angle stability. Compared with traditional liquid crystal-based metasurfaces, the measured results suggest that the recovery time of the proposed structure was reduced by half.

Active continuous control of terahertz wave based on a reflectarray element-liquid crystal-grating electrode hybrid structure.

In this work, a new and efficient terahertz reflective phase shifter is proposed. The phase shifter is composed of a metal-dielectric-metal structure with a double dipole patch array, as well as copper grating electrodes immersed within the nematic liquid crystal. More specifically, the employed copper grating electrodes consist of two sets of cross-distributed comb grids, whereas at each set of comb grids can be applied an external bias voltage separately.

Enhanced broadband absorption with a twisted multilayer metal-dielectric stacking metamaterial.

This study proposes and experimentally demonstrates enhanced broadband absorption with twisted multilayer metal-dielectric stacking. Compared with the traditional metal-dielectric pyramid, the resonance frequencies of the third-order magnetic resonances in the twisted quadrangular frustum redshifted obviously. Hence, the proposed structure enables an ultra-broadband absorption by combining the third-order magnetic resonances with the fundamental mode.

TM-polarized angle-dispersive metasurface for axisymmetric extension of beam steering angles.

Axisymmetric extension of beam steering angles by metasurfaces is of great interest due to its potential application in extending the angular scan range of existing phased arrays. This angle-multiplexed manipulation functionality requires anti-symmetrically angle-dispersive phase gradient, as well as anti-symmetric angular phase dispersion over continuous incident angles, which is difficult to be implemented by existing metasurfaces. In this work, a series of meta-atoms with asymmetric structures are developed to achieve the required phase response.

An Ultrathin, Triple-Band Metamaterial Absorber with Wide-Incident-Angle Stability for Conformal Applications at X and Ku Frequency Band.

An ultrathin and flexible metamaterial absorber (MA) with triple absorption peaks is presented in this paper. The proposed absorber has been designed in such a way that three absorption peaks are located at 8.5, 13.

Comb-Shaped Graphene Nanoribbon Bandpass Filter.

In this study, a novel comb-shaped graphene nanoribbon wideband bandpass filter for use at midinfrared frequencies is proposed. In addition, numerical investigation was carried outwith finite difference time-domain (FDTD) numerical simulations. The filter includes one graphene nanoribbon (GNR) waveguide laterally coupled to six perpendicular GNRs on each side.

Graphene-based wavelength demultiplexing structure.

A wavelength demultiplexing (WDM) structure based on graphene nanoribbon resonators is proposed and simulated using the finite-difference time-domain (FDTD) method. Based on a simple structure, the demultiplexing wavelength and transmission characteristics of the WDM can be tuned by adjusting the length of the resonator, the nanoribbon width, or the chemical potential of graphene within a relative broadband frequency range. Moreover, the mechanism of the proposed WDM structure is analyzed in detail using the theory of Fabry-Perot (F-P) resonance and temporal coupled-mode theory.

Electrically tunable liquid crystal terahertz device based on double-layer plasmonic metamaterial.

In this paper, a nematic liquid crystal (NLC)-based tunable terahertz (THz) plasmonic metamaterials (MMs) with large modulation depth (MD) and low insertion loss (IL) is designed and experimentally verified at THz frequencies. The proposed structure includes two-layered MM that is immersed in LC. The metal MM is used directly as electrode.

Wideband Metamaterial Absorbers Based on Conductive Plastic with Additive Manufacturing Technology.

This paper proposes a wideband and polarization-insensitive metamaterial absorber (MA) based on tractable conductive plastic, which is compatible with an additive manufacturing technology. We provide the design, fabrication, and measurement result of the proposed absorber and investigate its absorption principle. The performance characteristics of the structure are demonstrated numerically and experimentally.

Antireflection self-reference method based on ultrathin metallic nanofilms for improving terahertz reflection spectroscopy.

We present the potential of an antireflection self-reference method based on ultra-thin tantalum nitride (TaN) nanofilms for improving terahertz (THz) reflection spectroscopy. The antireflection self-reference method is proposed to eliminate mutual interference caused by unwanted reflections, which significantly interferes with the important reflection from the actual sample in THz reflection measurement. The antireflection self-reference model was investigated using a wave-impedance matching approach, and the theoretical model was verified in experimental studies.

Broadband terahertz metamaterial absorber based on tantalum nitride.

A broadband metamaterial absorber with a single layer of tantalum nitride (TaN) frequency selective surface layer, printed on a foam substrate, is presented. The proposed design has been numerically examined at the terahertz region. The results have shown that a wideband absorption with absorptivity greater than 90% was achieved in the frequency range 1.