Yijun Feng

Nanjing University | NJU · School of Electronic Science & Engineering

Metasurfaces enable a new paradigm of controlling electromagnetic waves by manipulating subwavelength artificial structures within just a fraction of wavelength. Despite the rapid growth, simultaneously achieving low-dimensionality, high transmission efficiency, real-time continuous reconfigurability, and a wide variety of re-programmable functions...

Janus monolayers, a class of two‐faced 2D materials, have received significant attention in electronics, due to their unusual conduction properties stemming from their inherent out‐of‐plane asymmetry. Their photonic counterparts recently allowed for the control of hydrogenation/dehydrogenation processes, yielding drastically different responses for...

Polarization control is paramount in tailoring light‐matter interactions; hence, its versatile manipulation plays an important role in science and technology. Metasurfaces have recently enacted diverse electromagnetic manipulations in polarization optics. However, they only support one or a few polarization functions in a single design. Here, an ar...

Reconfigurable metasurfaces have emerged as a versatile platform for reshaping the wireless environment into a desirable form at low cost. Despite the rapid growth, most of the existing metasurfaces only support reflection operation or transmission operation, only providing service coverage of backward or forward half‐space when they are used for w...

Since the discovery of wireless telegraphy in 1897, wireless communication via electromagnetic (EM) signals has become a standard solution to address increasing demand for information transfer in modern society. With the rapid growth of EM wave manipulation technique, programmable metasurface (PM) has emerged as a new type of wireless transmitter b...

Airy beams, accelerating optical beams with exotic properties of self-bending, self-healing and non-diffraction, are essential for a wide range of photonics applications. Recently, metasurfaces have provided an efficient platform for generating desired Airy beams within a thin thickness, but they suffer from the narrow bandwidth, especially for two...

The asymmetric transmission of electromagnetic waves can be flexibly manipulated by chiral metamaterials hybridized with tunable materials or active components. Here, we propose the concept of a direction-reversible tunable asymmetric transmission effect realized by chiral metamaterials. As the proof-of-concept, twisted metallic meta-sheets consist...

In this paper, a cascaded metasurface (MS) with circular-polarization-selective properties is proposed which can achieve high reflection for left-handed circular polarization (LCP) and high transmission for right-handed circular polarization (RCP). Such MS, constructed by cascading two kinds of MS sheets, can conduct decoupled geometric phase modul...

Polarization is one of the key characteristics of light; hence its versatile manipulation plays a pivotal role in wave‐matter interaction, communication, detection, etc. Although metasurfaces have emerged as a promising platform for polarization optics, most of them only support limited polarization controls even in reconfigurable fashion. Here, an...

Paper-based metamaterial is one kind of metamaterial based on the paper substrate, recently drawing a lot of attention due to its fascinating features. This paper proposes another fabrication solution to realize paper-based metamaterials by directly drawing instead of inkjet printing. The drawing tools we used included mechanical pencils, conductiv...

The concept of dual-polarized reconfigurable reflectarray (RRA) featuring dual-polarized beam control is proposed and demonstrated using a dual-channel programmable metasurface. The p-i-n diodes are incorporated into each metasurface element as the active components to provide independent phase control in two orthogonal polarization channels. By al...

A novel high-efficiency polarization-selective bifunctional metasurface (MS) is proposed, which can realize cross-polarized focusing transmission for left-handed circular polarization (LHCP) incidence and co-polarized specular reflection for right-handed circular polarization (RHCP) incidence. As an example of its practical application, the designe...

The independent tailoring of electromagnetic waves with different circular-polarized (CP) wavefront in both reflection and transmission channels is of broad scientific and technical interest, offering ultimate degrees of freedom in designing advanced devices with the merits of functionality integration and spatial exploitation. However, most metasu...

In this article, a single-sheet metasurface (MS) for independently manipulating the transmissive phase and amplitude of linearly polarized electromagnetic (EM) wave is proposed. The amplitude modulation is achieved via imposing a rotation angle to flexibly control the ratio of polarization conversion, while the phase modulation is realized by tunin...

Metasurfaces have provided a new paradigm to control electromagnetic waves by manipulating the spatially varying distribution of subwavelength artificial structures across the interface. Directional metasurfaces, a kind of metasurface with direction-dependent properties, possess different wave functionalities upon the incidence wave coming from opp...

At frequencies below 1 GHz, conventional microwave absorbers are limited by their large thickness or narrow absorption bandwidth; therefore, new techniques for efficient absorption for the lower microwave band are highly demanded. Here, we propose and fabricate an ultrathin tunable metamaterial absorber combining magnetic nanomaterials and metamate...

In this paper, a high-efficiency multifunctional full-space metasurface is proposed to independently control the reflection and transmission wavefront. As a proof of concept, a broadband reflect-transmit-array antenna with bidirectional high-gain beams is designed in the 5G millimeter-wave band around 26.8 GHz. The finally assembled antenna achieve...

Metasurfaces, the artificially planar electromagnetic structures, have exhibited strong potential for arbitrary electromagnetic wave-scattering control; however, most of the existing low-scattering metasurfaces are based on spatial phase redistributions to generate diffusive backscattering, leaving time dimension unexploited. The time-modulated mec...

During the past decade, metasurfaces have provided a versatile platform for controlling the amplitude, phase, and polarization of electromagnetic waves, thus showing great potential for developing compact photonic devices. However, compact and broadband terahertz (THz) components are still scarce for high‐speed communication and spectroscopy analys...

A three-dimensional lightweight metamaterial (MM) with ultra-wideband microwave absorption is proposed in this paper. Based on the concept of MMs, periodically arranged resistive films are introduced into the standing frame to form a standing lossy structure, which can introduce electric resonances in the gap between adjacent sub-wavelength unit ce...

Optical and microwave communication classically focus more on the magnitude manipulation of electromagnetic carriers. Recently, a multiplexing method utilizing orbital angular momentum (OAM) is developed, which has been an important study of communication art. Based on OAM multiplexing, a communication method that introduces Berry‐phase carriers is...

Kirigami technique, a method to reconfigure structures via mechanical approaches, has received much attention in material science, due to its versatile and unconventional structural transformations. The counterparts in the electromagnetic metamaterial field has recently allowed for the tunable control of electromagnetic responses. However, they are...

Reconfigurable Gradient Metasurfaces Kirigami, the ancient art of paper cutting, has recently been widely studied in modern science and technology. In article number 2107699, Ke Chen, Yijun Feng, and co‐workers use 3D kirigami configurations to achieve reconfigurable gradient metasurfaces. This concept combines continuous functional variation with...

Controlling the polarization and wavefront of light is essential for compact photonic systems in modern science and technology. This may be achieved by metasurfaces, a new platform that has radically changed the way people engineer wave–matter interactions. However, it still remains very challenging to generate versatile beams with independent wave...

In this paper, an active metamaterial (MM) absorber loaded with PIN diodes is proposed. By adjusting the bias currents of PIN diodes to change the value of the introduced equivalent resistance, the Q factors of multiple resonances of the whole structure are altered. Therefore, multiple broadband absorption states with moderate absorption performanc...

In this letter, an anisotropic metasurface is proposed for independent phase control upon orthogonal linearly-polarized waves, and is then applied to implement a low-profile wideband dual-polarized reflectarray antenna (RA) operating in Ku-band by integrating the metasurface with two Vivaldi feed sources. This RA can collimate both primary beams in...

Multichannel devices, which can manipulate multiple distinguished wavefronts like a kaleidoscope, are preferably desired for compact systems with higher integration and smaller footprint. Particularly, multiband metasurfaces are one of the intuitive and effective approaches to expand the number of the operation channels in meta-devices. In this wor...

Metasurface retroreflectors, which scatter the incident electromagnetic wave back to incoming direction, have received significant attention due to their compelling advantages of low profile and light weight compared with conventional bulky retroreflection devices. However, the current metasurface retroreflectors still have limitations in wide-angl...

Thin-thickness metasurfaces used for reducing radar cross section (RCS) have attracted much attention due to their promising prospects in many applications, like stealth techniques, antenna radomes, etc. One of the major challenges for antenna radome applications is to achieve inter-band high transmission in addition to broadband RCS reduction by a...

Active metasurfaces with dynamically switchable functionalities are highly in demands in various practical applications. In this paper, we experimentally present an active metasurface based on PIN diodes which can realize nearly perfect reflection, transmission and absorption in a single design. Such switchable functionalities are accomplished by c...

Conical beams have potential uses in wireless and satellite-based communication. In this study, we propose a method using a transmissive metasurface to achieve full control of the diverging effect of orbital angular momentum (OAM) modes to form the desired conical beam. A patch antenna functioning as the feed source is combined with the transmissiv...

Achieving multiple electromagnetic (EM) functionalities on a shared aperture in dual frequency bands is crucial for many applications; however, existing dual-band metasurfaces are affected by limited channels or narrow bandwidths. Herein, we propose a reflective coding metasurface that empowers four independent EM functionalities in quad-polarizati...

Programmable metasurfaces incorporating with tunable materials or components are emerging as an attractive option to realize reconfigurable manipulations of electromagnetic (EM) behaviors in real-time. Many efforts have been devoted to the realization of active EM manipulations of the metasurface and significant progress has been achieved, showing...

This paper presents an active cylindrical metasurface with spatial reconfigurability to achieve dynamic control of the RCS reduction. The proposed metasurface is designed based on the combination of microwave transmission network and Mie scattering. In particular, by modulating the spatial coding sequence of PIN diodes in meta-atoms, the surface im...

Since the electromagnetic (EM) absorbers have wide uses in many military and civilian applications, much effort has been devoted continuously to broadening the absorption bandwidth while making the thickness as thin as possible. In this paper, we present an ultra-wideband metamaterial absorber composed of periodic stepped-structures of magnetic mat...

Airy beams are essential for photonic applications, owing to their intriguing diffraction‐free, self‐accelerating, and self‐healing properties. Recently, 2D metasurfaces have offered great opportunities for generating Airy beams within subwavelength thickness. However, they suffer from the bottlenecks of low efficiency and narrow bandwidth, which m...

Arbitrarily controlling the reflection/transmission/absorption state of electromagnetic waves, especially their dynamical manipulation, is on high demand due to the growing development of practical optical devices and application systems. In this work, we present a scheme to dynamically manipulating terahertz wave reflection/transmission/absorption...

The recent development of metasurfaces offers a unique technique for the arbitrary control of electromagnetic waves by spatially manipulating their amplitudes and phases. However, real time control in metasurfaces typically depends solely on dynamical phase modulation, but lacks of the amplitude modulation. In this paper, the dynamical amplitude mo...

Controlling spin electromagnetic waves by ultra-thin Pancharatnam-Berry (PB) metasurfaces show promising prospects in the optical and wireless communications. One of the major challenge is to precisely control over the complex wavefronts and spatial power intensity characteristics without relying on massive algorithm optimizations, which requires i...

In this paper, a filtering balun is proposed based on spoof surface plasmon polariton (SSPP) structure which composes of symmetric H-shaped periodic metallic strip, two types of microstrip-slotline cross-coupling structures and the transition structure between them. The SSPP structure is applied to support odd mode propagation with 180° phase diffe...

Achieving independent control of amplitude and phase of electromagnetic (EM) wave by a thin flat device is very important in wireless and photonic communications. However, most of the reported metasurfaces, so far, have only realized simultaneous control of amplitude and phase for linearly polarized EM wave. This article presents a strategy to real...

Although metasurfaces have provided unprecedented control of electromagnetic (EM) waves, it is still challenging for the arbitrary manipulation of spatial radiation modes, energy distribution, and spin state of EM wave especially in microwave frequencies. Here, a cascaded dual‐helicity‐decoupled transmissive metasurface to realize independent modul...

This paper presents a low radar cross section (RCS) holographic antenna with enhanced gain based on a frequency-selective absorber (FSA). The proposed antenna consists of a feed monopole antenna, a holographic metasurface using slotted patches and a two-layered resistive metasurface. Within its operating band, the holographic metasurface manipulate...

Diffuse scatterings of electromagnetic (EM) waves by thin-thickness metasurfaces have promising prospects in many fields due to their abilities of significantly reducing the backward scatterings of targets. One of the major challenges is to further improve the working bandwidth. Here, we propose a binary geometric phase metasurface with high optica...

Artificially engineered metasurfaces provide extraordinary wave control at the subwavelength scale. However, metasurfaces proposed so far suffer due to limited bandwidths. In this paper, extremely thin metasurfaces made of single metallic layer is experimentally presented for ultra‐wideband operation from 9.3 to 32.5 GHz (with a fractional band of...

Graphene-enabled metamaterials have emerged as promising photoelectric devices for dynamically controlling the polarization of electromagnetic waves. However, it is still a key technological challenge to design a tunable metamaterial possessing more sufficient freedom for polarization manipulation. Here, we propose a graphene-enabled tunable multif...

In article number 1900472 by Ke Chen, Yijun Feng, and co‐workers, a coding methodology is reported that can enable a metasurface with independent 1‐bit phase codes for orthogonal spins. The proposed method is verified by two spin‐decoupled meta‐devices for either electromagnetic beam deflecting or generating multi‐beams carrying desired orbital ang...

Achieving distinct functionalities for electromagnetic (EM) waves with opposite handedness in a broad frequency range is highly desirable and essential for modern wireless communications and radar stealth. However, available functional meta‐devices still suffer from the issues of locked functionalities or spin‐decoupled properties but with limited...

Active metasurfaces pave a way for manipulating electromagnetic (EM) waves in real-time by incorporating with tunable materials or components, emerging as an attractive solution to achieve versatile EM functionalities in dynamic fashions. However, most of the active metasurfaces demonstrated so far only support tunable responses for a certain sing...

Controlling the polarization and wavefront of light is essential for compact photonic systems in modern science and technology. This may be achieved by metasurfaces, a new platform that has radically changed the way people engineer wave-matter interactions. However, it still remains very challenging to generate versatile beams with arbitrary and in...