Broadband Metamaterial Reflectors for Polarization Manipulation Based on Cross/Ring Resonators

We presented the investigation of broadband metamaterial reflector for polarization manipulation based on cross/ring resonators. It is demonstrated that the meta¬material reflector can convert the linearly polarized inci¬dent wave to its cross polarized wave or circularly polar¬ized wave. Due to the multiple resonances at neighboring frequencies, the proposed reflector presents broadband property and high efficiency. The measured fraction band¬width of cross polarization conversion is 55.5% with effi¬ciency higher than 80%. Furthermore, a broadband circu¬lar polarizer is designed by adjusting the dimension para¬meters and the measured fraction bandwidth exceeds 30%

A C/X Dual-band Wide-angle Reflective Polarization Rotation Metasurface

In this paper, a C/X dual-band wide-angle re¬flective polarization rotation metasurface (PRMS) with high rotation efficiency is proposed and realized. Aiming to miniaturize the size of the unit cell, a metallic flower-like shape ring is selected to extend the current path and the 45 degree slanting stitch along diagonal direction is used to form the asymmetric structure. The simulated results show that the proposed PRMS achieves polarization rotation at 4.61 GHz and 8.67 GHz with high efficiency, at which the linear polarization incident wave is converted into its orthogonal polarization after reflection. Furthermore, the high polarization rotation efficiency of the proposed PRMS is maintained under an oblique incident direction from 0° to 60°. To verify the simulated results, the proposed PRMS is fabricated and measured. The measured results are in good accordance with the simulated ones

A dual-patch polarization rotation reflective surface and its application to ultra-wideband RCS reduction

© 2017 IEEE. An ultra-wideband polarization rotation reflective surface (PRRS) with a high polarization conversion ratio (PCR) is proposed, which can reflect a linearly polarized incident wave with 90° polarization rotation. The unit cell of the proposed PRRS consists of a square and L-shaped patches printed on a substrate, which is covered by a superstrate and backed by a metallic ground. The two patches are connected to the ground using two metallic vias, respectively. Compared with the previously reported PRRS, the polarization rotation bandwidth of the proposed PRRS is enhanced from 49% to 97% with a high PCR of 96%. The frequency responses within the operation frequency band are consistent under oblique incident waves. Furthermore, the designed PRRS is applied to the ultra-wideband radar cross-section (RCS) reduction by forming a checkerboard surface. A 10-dB RCS reduction is achieved over an ultrawideband of 98%. To validate the simulation results, a prototype of the checkerboard surface is fabricated and measured. A good agreement between the experimental and simulation results is obtained

Wideband Cross Polarization Rotation based on Reflective Anisotropic Surfaces

This paper presents a new design to broaden polarization conversion ratio (PCR) bandwidth utilizing reflective surfaces. The proposed design is based on anisotropic surfaces for linearly polarized electromagnetic waves. The combination of a traditional two-corner-cut square patch and a two-layer substrate with defected ground structure contributes to PCR bandwidth expansion and size reduction. The experimental results indicate that PCR fractional bandwidth is higher than 121% in 5.4-22 GHz band for both x- and y-polarized waves and the conversion efficiency is greater than 90%. In addition, the proposed structure is approximately robust under oblique incidences, which verifies the applicability of the structure in a practical environment. The experimental results are in excellent agreement with simulated ones. The reflective surface with wideband PCR can be utilized in various practical applications, such as radiometer, reflector antennas, remote sensors, and imaging sensors

Multifunction full space graphene assisted metasurface

In recent years, there has been notable advancement in programmable metasurfaces, primarily attributed to their cost-effectiveness and capacity to manipulate electromagnetic (EM) waves. Nevertheless, a significant limitation of numerous available metasurfaces is their capability to influence wavefronts only in reflection mode or transmission mode, thus catering to only half of the spatial coverage. To the best of our knowledge and for the first time, a novel graphene-assisted reprogrammable metasurface that offers the unprecedented capability to independently and concurrently manipulate EM waves within both half-spaces has been introduced in the THz frequency band

Wideband RCS reduction based on a simple chessboard metasurface

To avoid being detected by radar, it is necessary to reduce stealthy military platforms' radar cross section (RCS). The operation of overlaying the metasurface (MS) on the targets is a good solution. A simple chessboard MS structure that can achieve low RCS over a large bandwidth is proposed. Only one unit cell is used to construct the MS. First, the unit cell working in 0.5 and 1−λ modes is designed to achieve a stable phase difference of 180° for y- and x-polarized waves. Then, the unit cells and rotated ones are used to form a chessboard structure with different distributions. The compared results show that the chessboard MS with 2 × 2 quadrants can facilitate the widest 10 dB RCS reduction band of 111% and the largest RCS reduction. The proposed structure exhibits excellent RCS reduction even when irradiated by y- and x-polarized waves at an oblique incidence of 30°

A New Coding Metasurface for Wideband RCS Reduction

In this paper, two novel artificial magnetic conductors (AMC) structures are designed to realize 180 degrees of phase difference in a wideband frequency. These two AMC structures are encoded as unit “0”and unit “1”, respectively. By using Simulated Annealing algorithm, the coding sequences of the coding metasurface can be designed, so that the radar cross section (RCS) reduction can be realized as well. Compared with the metallic surface, the simulation and measurement results of this presented coding metasurface indicate that this coding metasurface can significantly realize RCS reduction under normally incident electromagnetic (EM) waves from 7GHz to 20GHz, which is 96.3%, and the RCS under obliquely incident waves also can be dramatically reduced as well, furthermore, the RCS reduction of this coding metasurface is better than that of traditional chessboard surface