Full-space metasurfaces (MSs) attract significant attention in the field of electromagnetic (EM) wave manipulation due to their advantages of functionality integration, spatial integration and wide applications in modern communication systems. However, almost all reported full-space metasurfaces are realized by multilayer dielectric cascaded structures, which not only has the disadvantages of high cost and complex fabrication but also is inconvenient to device integration. Thus, it is of great interest to achieve high-efficiency full-space metasurfaces through simple design and easy fabrication procedures. Here, we propose a full-space MS that can efficiently manipulate the circularly polarized (CP) waves in dual frequency bands by only using a single substrate layer, the reflection and transmission properties can be independently controlled by rotating the optimized meta-structures on the metasurface. Our full-space metasurface has the potential to design multifunctional devices. To prove the concept, we fabricate the device and measured it in microwave chamber. For the reflection mode, our metasurface can behave as a CP beam splitter at the frequency of f1 = 8.3 GHz and exhibit high efficiencies in the range of 84.1%–84.9%. For the transmission mode, our metasurface acts as a meta-lens at the frequency of f2 = 12.8 GHz for the LCP incidence, and the measured relative efficiency of the meta-lens reaches about 82.7%. Our findings provide an alternative way to design full-space metasurfaces and yield many applications in EM integration systems.

In this paper, we propose an approach to design metasurfaces to realize superior performance for monostatic and bistatic radar cross section (RCS) reduction within a wide bandwidth. By engineering four subarrays to exhibit different hybrid focusing-linear phases within a metasurface, nearly uniform diffusive scattering can be inherently guaranteed. As an illustration, we design and fabricate a proof-of-prototype metasurface and experimentally demonstrate its wave-diffusion performances. Numerical and experimental results both show that the thin metasurface enables a monostatic/bistatic 10 dB RCS reduction over a broad bandwidth ranging from 7.2 to 17.2 GHz. In addition, more than 10 dB RCS reduction performance is preserved within a band of 7.8 ∼ 14.2 GHz even for off-normal incidence up to 60°. Our approach features broadband, polarization insensitive, wide incident angles and easy design without time-consuming optimization, promising great potentials in applications of low-scattering stealth.

Absorbers have high potential application values in the military field, such as electronic screening, radar cross-section reduction and invisible cloaking. However, most methods have the defects of narrow bandwidth, low absorptivity, complex three-dimensional structure and fixed polarizations. In this paper, we realize an ultra-broadband and full-polarization planar metamaterial absorber (PMA) with a three-layer composite structure, which exhibits multi-resonant and impedance matching properties by combining the ultra-light foams and indium tin oxide (ITO) films. The bottom two layers achieve a high-efficiency absorption rate at the low and medium spectrum, while the upper layer realizes a absorption property at a high frequency. Also, an equivalent circuit model is extracted to explain its operating mechanism. The experimental results show that our meta-absorber can achieve great absorber performance of better than 90% within 1-18 GHz for full-polarization incident waves, which is in great agreement with the numerical simulations. Moreover, our device is insensitive to oblique incidences and polarizations and possesses the physical characteristics of an ultralight, weighing 0.6 kg for a square meter, which is only 1/85.0-1/126.7 of the conventional absorbers under the same size. All these excellent performances determine that our research can be a good candidate for military stealth materials.

Metasurfaces attract significant attention and are widely applied in modern communication systems due to their powerful capabilities to control the polarization, amplitude, and phase of electromagnetic waves. However, it is considerably challenging to control polarization and amplitude of incident waves for a passive metasurface. Specifically, we integrate the transmission and reflection functions by loading a middle layer with PIN diodes while the upper and lower structures are used to manipulate the polarizations of incident waves. As a proof of concept, we fabricate a sample having 18  ×  18 meta-atoms. Beam deflectors for the circularly polarized waves dependent on Helicity are realized when the PIN diodes are turned off. A transmissive polarization converter for x-polarization and a reflective polarization keeper for y -polarization are achieved as the PIN diodes are turned on. More importantly, the functionalities exhibit extremely high efficiencies in the range 86.4%–90.3% for reflective functionalities and 75.4% for transmissive functionalities. Our findings provide a new method to design multifunctionalities metasurface via tunable devices and yield many applications in multifunctional systems.

Spoof surface plasmon polariton (SSPP) antennas are of particular importance in communication and radar systems. Currently available SSPP radiation devices are limited to low performance with high side‐lobes because it is extremely challenging to accurately control the wave vector of SSPP and the inherent momentum mismatch between the SSPP and spatial waves. Inspired by the optical principle of reversibility, high‐performance radiation control of SSPP is proposed to be achieved with transmissive phase gradient metasurface (TPGM). The TPGM, placed a meticulously optimized distance above the SSPP propagation structure, can provide an additional opposite wave vector to match the momentum between the SSPP and spatial waves. When the propagating SSPP transmits on the TPGM, it can be decoupled into the free space accurately and flexibly. Numerical results coincide well with the measurements, indicating that the radiation control of SSPP achieves high‐performance and low side‐lobe within 9 to 10.5 GHz with the measured radiation efficiency higher than 50%. The measured maximum efficiency appears at 9.8 GHz for 69%. Thanks to the flexible and accurate manipulation of the dispersion relation of SSPP provided by TPGM, the findings may open an avenue in achieving larger angle scanning antenna.