Metasurfaces are artificially structured thin films with unusual properties on demand. Different from metamaterials, the metasurfaces change the electromagnetic waves mainly by exploiting the boundary conditions, rath...Metasurfaces are artificially structured thin films with unusual properties on demand. Different from metamaterials, the metasurfaces change the electromagnetic waves mainly by exploiting the boundary conditions, rather than the constitutive parameters in three dimensional(3D) spaces. Despite the intrinsic similarities in the operational principles, there is not a universal theory available for the understanding and design of metasurface-based devices. In this article, we propose the concept of metasurface waves(M-waves) and provide a general theory to describe the principles of them. Most importantly, it is shown that the M-waves share some fundamental properties such as extremely short wavelength, abrupt phase change and strong chromatic dispersion, which make them different from traditional bulk waves. It is shown that these properties can enable many important applications such as subwavelength imaging and lithography, planar optical devices, broadband anti-reflection, absorption and polarization conversion. Our results demonstrated unambiguously that traditional laws of diffraction, refraction, reflection and absorption should be revised by using the novel properties of M-waves. The theory provided here may pave the way for the design of new electromagnetic devices and further improvement of metasurfaces. The exotic properties of metasurfaces may also form the foundations for two new sub-disciplines called "subwavelength surface electromagnetics" and "subwavelength electromagnetics".展开更多
Wide field-of-view(FOV)optics are essential components in many optical systems,with applications spanning imaging,display,sensing,and beam steering.Conventional refractive wide FOV optics often involve multiple stacke...Wide field-of-view(FOV)optics are essential components in many optical systems,with applications spanning imaging,display,sensing,and beam steering.Conventional refractive wide FOV optics often involve multiple stacked lenses,resulting in large size and weight as well as high cost.Metasurface lenses or metalenses promise a viable solution to realizing wide FOV optics without complex lens assembly.We review the various architectures of wide FOV metalenses,elucidate their fundamental operating principles and design trade-offs,and quantitatively evaluate and contrast their imaging performances.Emerging applications enabled by wide FOV metasurface optics are also discussed.展开更多
Circularly polarized （CP） lens antenna has been applied to numerous wireless communication systems based on its unique advantages such as high antenna gain, low manufacturing cost, especially stable data transmissio...Circularly polarized （CP） lens antenna has been applied to numerous wireless communication systems based on its unique advantages such as high antenna gain, low manufacturing cost, especially stable data transmission between the transmitter and the receiver. Unfortunately, current available CP lens antennas mostly suffer from high profile, low aperture efficiency as well as complex design. In this paper, we propose an ultra-thin CP lens antenna based on the designed single- layered Pancharatnam-Berry （PB） transparent metasurface with focusing property. The PB metasurface exhibits a high transmissivity, which ensures a high efficiency of the focusing property. Launched the metasurface with a CP patch antenna at its focal point, a low-profile lens antenna is simulated and measured. The experimental results show that our lens antenna exhibits a series of advantages including high radiation gain of 20.7 dB, aperture efficiency better than 41.3%, and also narrow half power beam width （HPBW） of 13°at about 14GHz. Our finding opens a door to realize ultra-thin transparent metasurface with other functionalities or at other working frequencies.展开更多
利用不同厚度的亚波长介质块实现0~2π的相位变化,并基于惠更斯人工电磁表面原理设计了工作于28 GHz通信频段的全介质电磁透镜,该电磁透镜的焦距与口径比（F/D）为0.15。通过3D打印制备该电磁透镜,并将其与基片集成波导（SIW）贴片天线...利用不同厚度的亚波长介质块实现0~2π的相位变化,并基于惠更斯人工电磁表面原理设计了工作于28 GHz通信频段的全介质电磁透镜,该电磁透镜的焦距与口径比（F/D）为0.15。通过3D打印制备该电磁透镜,并将其与基片集成波导（SIW）贴片天线进行集成,构造了超低剖面的宽带透镜天线。全波分析与实验测量结果显示该电磁透镜能够将原SIW贴片天线的增益提高7 d B左右,而将3 d B波束宽度减小到10°左右,同时该透镜天线系统还具有良好的低副瓣。展开更多
A metasurface unit is designed operating at 2–20 GHz to enhance the gain and radiation performance of an antipodal Vivaldi antenna(AVA).The unit has a simple structure,stable ultra-wideband performance,high permittiv...A metasurface unit is designed operating at 2–20 GHz to enhance the gain and radiation performance of an antipodal Vivaldi antenna(AVA).The unit has a simple structure,stable ultra-wideband performance,high permittivity,and can independently modulate two polarization modes electromagnetic waves.We analyze the current distribution on the unit and extract equivalent characteristic parameters to verify the ability of independent modulation on two polarization modes electromagnetic waves.The designed metasurface unit is integrated into the aperture of the AVA and forms the metasurface lens(ML)for guiding the propagation of electromagnetic waves.Two types of ML are proposed and integrated into the AVA to design antennas Ant1 and Ant2.The modulation effect of the lens on the electromagnetic wave is analyzed from the perspective of electric field amplitude and phase,and the final design is obtained.From the optimized design results,the AVA and the proposed Ant2 are fabricated and measured,and the measurement results are in good agreement with the simulation ones.The impedance bandwidth measured by Ant2 basically covers the 2–18 GHz frequency band.Compared with the conventional AVA,the gain of the proposed Ant2 is increased by 0.6–3.7 d B,the sidelobe level is significantly reduced,and the directivity has also been clearly improved.展开更多
A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface（GPGM）.With an accuracy control of the transmiss...A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface（GPGM）.With an accuracy control of the transmission phase and also the high transmission amplitude,the GPGM is capable of manipulating an electromagnetic wave arbitrarily.A focusing transmission lens working at Ku band is well optimized with the F /D of 0.32.A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation.For further application,an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration,simple structure,and low cost.Numerical and experimental results coincide well,indicating the advantages of the antenna system,such as a high gain of 17.6 d B,the axis ratio better than 2 d B,a high aperture efficiency of 41%,and also a simple fabrication process based on the convenient print circuit board technology.The good performance of the proposed antenna indicates promising applications in portable communication systems.展开更多
An isotropic electromagnetic （EM） lens based on Huygens＇ metasurface is proposed for 28.0 GHz lens antenna design. The lens consists of a series of non-resonant and subwavelength metallic patterns etched on both si...An isotropic electromagnetic （EM） lens based on Huygens＇ metasurface is proposed for 28.0 GHz lens antenna design. The lens consists of a series of non-resonant and subwavelength metallic patterns etched on both sides of an ultrathin dielectric substrate. Both electric and magnetic responses are introduced to realize desired abrupt phase change and high-efficiency transmission for the secondary wavelets in the incident wavefront. Then, a substrate-integrated waveguide （SIW） fed patch antenna is combined with the lens as the primary feed to form a low-profile lens antenna system. The simulated and measured results coincide with each other, and demonstrate that the prototype realizes 8.8 dB-12.6 dB gain increment and low side-lobe levels over the bandwidth of 26.7 GHz-30.0 GHz. The novel design leads to a low-profile, light weight, and low-cost antenna solution in a wireless communication system.展开更多
基金supported by the National Program on Key Basic Research Project(Grant No.2013CBA01700)the National Natural Science Foundation of China(Grant No.61138002)
文摘Metasurfaces are artificially structured thin films with unusual properties on demand. Different from metamaterials, the metasurfaces change the electromagnetic waves mainly by exploiting the boundary conditions, rather than the constitutive parameters in three dimensional(3D) spaces. Despite the intrinsic similarities in the operational principles, there is not a universal theory available for the understanding and design of metasurface-based devices. In this article, we propose the concept of metasurface waves(M-waves) and provide a general theory to describe the principles of them. Most importantly, it is shown that the M-waves share some fundamental properties such as extremely short wavelength, abrupt phase change and strong chromatic dispersion, which make them different from traditional bulk waves. It is shown that these properties can enable many important applications such as subwavelength imaging and lithography, planar optical devices, broadband anti-reflection, absorption and polarization conversion. Our results demonstrated unambiguously that traditional laws of diffraction, refraction, reflection and absorption should be revised by using the novel properties of M-waves. The theory provided here may pave the way for the design of new electromagnetic devices and further improvement of metasurfaces. The exotic properties of metasurfaces may also form the foundations for two new sub-disciplines called "subwavelength surface electromagnetics" and "subwavelength electromagnetics".
基金Funding support was provided by the Defense Advanced Research Projects Agency,the Defense Sciences Office(DSO)Programs:EXTREME Optics and Imaging(EXTREME)under Agreement No.HR00111720029the Enhanced Night Vision in Eyeglass Form(ENVision)under Agreement No.HR001121S0013.
文摘Wide field-of-view(FOV)optics are essential components in many optical systems,with applications spanning imaging,display,sensing,and beam steering.Conventional refractive wide FOV optics often involve multiple stacked lenses,resulting in large size and weight as well as high cost.Metasurface lenses or metalenses promise a viable solution to realizing wide FOV optics without complex lens assembly.We review the various architectures of wide FOV metalenses,elucidate their fundamental operating principles and design trade-offs,and quantitatively evaluate and contrast their imaging performances.Emerging applications enabled by wide FOV metasurface optics are also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.61372034)
文摘Circularly polarized （CP） lens antenna has been applied to numerous wireless communication systems based on its unique advantages such as high antenna gain, low manufacturing cost, especially stable data transmission between the transmitter and the receiver. Unfortunately, current available CP lens antennas mostly suffer from high profile, low aperture efficiency as well as complex design. In this paper, we propose an ultra-thin CP lens antenna based on the designed single- layered Pancharatnam-Berry （PB） transparent metasurface with focusing property. The PB metasurface exhibits a high transmissivity, which ensures a high efficiency of the focusing property. Launched the metasurface with a CP patch antenna at its focal point, a low-profile lens antenna is simulated and measured. The experimental results show that our lens antenna exhibits a series of advantages including high radiation gain of 20.7 dB, aperture efficiency better than 41.3%, and also narrow half power beam width （HPBW） of 13°at about 14GHz. Our finding opens a door to realize ultra-thin transparent metasurface with other functionalities or at other working frequencies.
文摘利用不同厚度的亚波长介质块实现0~2π的相位变化,并基于惠更斯人工电磁表面原理设计了工作于28 GHz通信频段的全介质电磁透镜,该电磁透镜的焦距与口径比（F/D）为0.15。通过3D打印制备该电磁透镜,并将其与基片集成波导（SIW）贴片天线进行集成,构造了超低剖面的宽带透镜天线。全波分析与实验测量结果显示该电磁透镜能够将原SIW贴片天线的增益提高7 d B左右,而将3 d B波束宽度减小到10°左右,同时该透镜天线系统还具有良好的低副瓣。
基金Project supported by the Open Fund for the Key Laboratory of Complex Systems Control and Intelligent Collaborative Technology,China(No.CSCIC191001)。
文摘A metasurface unit is designed operating at 2–20 GHz to enhance the gain and radiation performance of an antipodal Vivaldi antenna(AVA).The unit has a simple structure,stable ultra-wideband performance,high permittivity,and can independently modulate two polarization modes electromagnetic waves.We analyze the current distribution on the unit and extract equivalent characteristic parameters to verify the ability of independent modulation on two polarization modes electromagnetic waves.The designed metasurface unit is integrated into the aperture of the AVA and forms the metasurface lens(ML)for guiding the propagation of electromagnetic waves.Two types of ML are proposed and integrated into the AVA to design antennas Ant1 and Ant2.The modulation effect of the lens on the electromagnetic wave is analyzed from the perspective of electric field amplitude and phase,and the final design is obtained.From the optimized design results,the AVA and the proposed Ant2 are fabricated and measured,and the measurement results are in good agreement with the simulation ones.The impedance bandwidth measured by Ant2 basically covers the 2–18 GHz frequency band.Compared with the conventional AVA,the gain of the proposed Ant2 is increased by 0.6–3.7 d B,the sidelobe level is significantly reduced,and the directivity has also been clearly improved.
基金Project supported by the National Natural Science Foundation of China(Grant No.61372034)
文摘A new method to design an ultra-thin high-gain circularly-polarized antenna system with high efficiency is proposed based on the geometrical phase gradient metasurface（GPGM）.With an accuracy control of the transmission phase and also the high transmission amplitude,the GPGM is capable of manipulating an electromagnetic wave arbitrarily.A focusing transmission lens working at Ku band is well optimized with the F /D of 0.32.A good focusing effect is demonstrated clearly by theoretical calculation and electromagnetic simulation.For further application,an ultra-thin single-layer transmissive lens antenna based on the proposed focusing metasurface operating at 13 GHz is implemented and launched by an original patch antenna from the perspective of high integration,simple structure,and low cost.Numerical and experimental results coincide well,indicating the advantages of the antenna system,such as a high gain of 17.6 d B,the axis ratio better than 2 d B,a high aperture efficiency of 41%,and also a simple fabrication process based on the convenient print circuit board technology.The good performance of the proposed antenna indicates promising applications in portable communication systems.
基金supported by the National Natural Science Foundation of China (61401229)the Science and Technology Project of Jiangsu Province (BE2015002-2)+1 种基金the Open Research Program of the State Key Laboratory of Millimeter Waves (K201616)the Nanjing University of Posts and Telecommunications Scientific Foundation (NY215137)
文摘An isotropic electromagnetic （EM） lens based on Huygens＇ metasurface is proposed for 28.0 GHz lens antenna design. The lens consists of a series of non-resonant and subwavelength metallic patterns etched on both sides of an ultrathin dielectric substrate. Both electric and magnetic responses are introduced to realize desired abrupt phase change and high-efficiency transmission for the secondary wavelets in the incident wavefront. Then, a substrate-integrated waveguide （SIW） fed patch antenna is combined with the lens as the primary feed to form a low-profile lens antenna system. The simulated and measured results coincide with each other, and demonstrate that the prototype realizes 8.8 dB-12.6 dB gain increment and low side-lobe levels over the bandwidth of 26.7 GHz-30.0 GHz. The novel design leads to a low-profile, light weight, and low-cost antenna solution in a wireless communication system.
