scispace - formally typeset
Search or ask a question
Author

Haipeng Li

Bio: Haipeng Li is an academic researcher from National University of Defense Technology. The author has contributed to research in topics: Antenna (radio) & Polarization (waves). The author has an hindex of 13, co-authored 27 publications receiving 667 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a high-gain transmitting lens antenna by employing layered phase-gradient metasurface (MS) was proposed to focus the propagating plane wave to a point with high efficiency.
Abstract: We propose a high-gain transmitting lens antenna by employing layered phase-gradient metasurface (MS). The MS is engineered to focus the propagating plane wave to a point with high efficiency. An X-band patch antenna is placed at the focal point of the MS as a feed source, and then the quasi-spherical wave emitted by the source is transformed to plane wave. Due to the successful conversion of quasi-spherical wave to plane wave, the beam width of the patch antenna has been decreased 66° and the gain has been enhanced 11.6 dB. The proposed lens antenna not only opens up a new route for the applications of phase-gradient MS in microwave band, but also affords an alternative for high-gain antenna.

189 citations

Journal ArticleDOI
TL;DR: A tunable metasurface incorporating diodes as active elements can dynamically control the reflection phase of EM waves, and thus exhibits unprecedented capabilities to manipulate the helicity of incident circular-polarized (CP) EM wave.
Abstract: Manipulating the polarization states of electromagnetic (EM) waves, a fundamental issue in optics, attracted intensive attention recently. However, most of the devices realized so far are either too bulky in size, and/or are passive with only specific functionalities. Here we combine theory and experiment to demonstrate that, a tunable metasurface incorporating diodes as active elements can dynamically control the reflection phase of EM waves, and thus exhibits unprecedented capabilities to manipulate the helicity of incident circular-polarized (CP) EM wave. By controlling the bias voltages imparted on the embedded diodes, we demonstrate that the device can work in two distinct states. Whereas in the “On” state, the metasurface functions as a helicity convertor and a helicity hybridizer within two separate frequency bands, it behaves as a helicity keeper within an ultra-wide frequency band in the “Off” state. Our findings pave the way to realize functionality-switchable devices related to phase control, such as frequency-tunable subwavelength cavities, anomalous reflectors and even holograms.

114 citations

Journal ArticleDOI
TL;DR: In this paper, phase and amplitude control reflected metasurface (MS) antennas have been proposed to simultaneously manipulate the antenna's main lobe and sidelobes, achieving a high gain of 20.7 dB at 10 GHz.
Abstract: The metasurface (MS) antenna is an important microwave component in the communication system due to its unique beam radiation capability. However, current studies mainly pay attention to improve the performance of the main lobe of the MS antenna, leaving the sidelobe unexplored although it is also essential in some practical applications. In this paper, several phase- and amplitude-control reflected MSs have been proposed to simultaneously manipulate the antenna’s main lobe and sidelobes. The MSs consist of modified I-shaped particles which can independently manipulate the phases and amplitudes of the cross-polarization waves by changing the split size and orientation, respectively. A focusing phase distribution and different Taylor amplitude distributions have been fixed on the MSs. By illuminating the MSs with a self-made antenna, we have successfully designed four MS antennas. For the first antenna, we solely pay attention to improve the main lobe and achieve a high gain of 20.7 dB at 10 GHz. For the other three antennas, we also aim to manipulate their sidelobes. The resultant sidelobe levels (SLLs) are about −25 dB in the $xoz$ plane for the second antenna, −29 dB in the $yoz$ plane for the third antenna, and both of the former two characteristics for the fourth antenna. Compared with the first MS antenna, the last three antennas suffer from gain reductions of 2, 1.7, and 3 dB, respectively. These proposed MS antennas provide a new way to manipulate both main-lobe levels and SLLs and also greatly promote the integration of MSs and antennas.

102 citations

Journal ArticleDOI
TL;DR: In this paper, a single-layer focusing gradient metasurface (MS) built by one element group is proposed, which can focus the propagating plane wave on a point and a patch antenna is placed at its focus to build a high-gain planar lens antenna.
Abstract: A single-layer focusing gradient metasurface (MS) built by one element-group is proposed. The element-group is designed by well connecting the phase shift range of two similar single-layer elements under the condition of transmitting efficiencies over 0.7. The proposed MS can focus the propagating plane wave on a point and a patch antenna is placed at its focus to build a high-gain planar lens antenna. This lens antenna achieves pencil-shaped far-field radiation pattern with a simulation peak gain of 16.7 dB at 10 GHz. The single-layer structure makes it easy to fabricate the MS with low profile and satisfying performances. Finally, the MS and the patch antenna are fabricated, assembled, and measured. The measured results are in good agreement with the simulations.

101 citations

Journal ArticleDOI
TL;DR: In this paper, a compound meta-atom can control the transmitted phase by modulating the gap size of a modified I-shaped structure, and can set the transmitted amplitude by rotating the structure between outer gratings.
Abstract: Metasurfaces continue to drawn significant attention for manipulating light waves, but most to date have controlled either the phase profile or the amplitude profile of the output light---not both. This study proposes a strategy to control the transmitted phase and amplitude, over a wide band. A compound meta-atom can control the transmitted phase by modulating the gap size of a modified I-shaped structure, and can set the transmitted amplitude by rotating the structure between outer gratings. A proof-of-concept experiment points to the possibility of realizing arbitrary beam shapes.

78 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, the authors present an overview on the development of metasurfaces, including both homogeneous and inhomogeneous ones, focusing particularly on their working principles, the fascinating wave-manipulation effects achieved both statically and dynamically, and the representative applications so far realized.
Abstract: Metasurfaces are ultrathin metamaterials consisting of planar electromagnetic (EM) microstructures (e.g., meta-atoms) with pre-determined EM responses arranged in specific sequences. Based on careful structural designs on both meta-atoms and global sequences, one can realize homogenous and inhomogeneous metasurfaces that can possess exceptional capabilities to manipulate EM waves, serving as ideal candidates to realize ultracompact and highly efficient EM devices for next-generation integration-optics applications. In this paper, we present an overview on the development of metasurfaces, including both homogeneous and inhomogeneous ones, focusing particularly on their working principles, the fascinating wave-manipulation effects achieved both statically and dynamically, and the representative applications so far realized. Finally, we also present our own perspectives on possible future directions of this fast-developing research field in the conclusion.

300 citations

Journal ArticleDOI
TL;DR: In this paper, the authors systematically summarized and analyzed the information and digital convolution aspects of metamaterials and metasurfaces with particular emphasis on the information-and-digital convolution aspect.
Abstract: Traditionally, “metamaterials” have been described by effective medium parameters due to the subwavelength nature of unit particles. The continuous nature of medium parameters makes traditional metamaterials behave as analog metamaterials. Recently, the concept of coding metamaterials or “metasurfaces” has been proposed, in which metamaterials are characterized by digital coding particles of “0” and “1” with opposite phase responses. It has been demonstrated that electromagnetic waves can be manipulated by changing the coding sequences of “0” and “1”. The coding particles provide a link between the physical world and digital world, leading to digital metamaterials and even field programmable metamaterials, which can be used to control electromagnetic waves in real time. The digital coding representation of metamaterials or metasurfaces can also allow the concepts and signal processing methods in information science to be introduced to physical metamaterials, thereby realizing extreme control of electromagnetic waves. Such studies have set the foundation of information metamaterials and metasurfaces. In this review article, the coding, digital, and field programmable metamaterials and metasurfaces are systematically summarized and analyzed with particular emphases on the information and digital convolution aspects. The future trend of information metamaterial/metasurface is predicted, including software-defined metamaterials/metasurfaces and cognitive metamaterials/metasurfaces.

287 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review the recent progress in tunable and reconfigurable metasurfaces and metadevices through different active materials deployed together with the different control mechanisms including electrical, thermal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.
Abstract: Metasurfaces, two-dimensional equivalents of metamaterials, are engineered surfaces consisting of deep subwavelength features that have full control of the electromagnetic waves. Metasurfaces are not only being applied to the current devices throughout the electromagnetic spectrum from microwave to optics but also inspiring many new thrilling applications such as programmable on-demand optics and photonics in future. In order to overcome the limits imposed by passive metasurfaces, extensive researches have been put on utilizing different materials and mechanisms to design active metasurfaces. In this paper, we review the recent progress in tunable and reconfigurable metasurfaces and metadevices through the different active materials deployed together with the different control mechanisms including electrical, thermal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.

286 citations

Journal ArticleDOI
TL;DR: Gap-surface plasmon metamaterials have attracted increasing attention in recent years because of the ease of fabrication and unprecedented control over reflected or transmitted light while featuring relatively low losses even at optical wavelengths as mentioned in this paper.
Abstract: Abstract Plasmonic metasurfaces, which can be considered as the two-dimensional analog of metal-based metamaterials, have attracted progressively increasing attention in recent years because of the ease of fabrication and unprecedented control over the reflected or transmitted light while featuring relatively low losses even at optical wavelengths. Among all the different design approaches, gap-surface plasmon metasurfaces – a specific branch of plasmonic metasurfaces – which consist of a subwavelength thin dielectric spacer sandwiched between an optically thick metal film and arrays of metal subwavelength elements arranged in a strictly or quasi-periodic fashion, have gained awareness from researchers working at practically any frequency regime as its realization only requires a single lithographic step, yet with the possibility to fully control the amplitude, phase, and polarization of the reflected light. In this paper, we review the fundamentals, recent developments, and opportunities of gap-surface plasmon metasurfaces. Starting with introducing the concept of gap-surface plasmon metasurfaces, we present three typical gap-surface plasmon resonators, introduce generalized Snell’s law, and explain the concept of Pancharatnam-Berry phase. We then overview the main applications of gap-surface plasmon metasurfaces, including beam-steerers, flat lenses, holograms, absorbers, color printing, polarization control, surface wave couplers, and dynamically reconfigurable metasurfaces. The review is ended with a short summary and outlook on possible future developments.

236 citations