Yan Shi

Prof. Dr. Yan Shi

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Academic Career Length

21Years (2006-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2019 in IEEE Antennas and Wireless Propagation Letters
Verified
Journal Article
Closed access
JHJiaqi Han
Jiaqi Han
Long LiLong Li
Long Li
GLGuangyao Liu
Guangyao Liu
ZWZhao Wu
Zhao Wu
YSYan Shi
Yan Shi
In this paper, a wideband 1-bit 12×12 reconfigurable beam-scanning reflectarray is designed, fabricated, and measured. The 1-bit reconfigurable element is realized by soldering PIN diode into a slotted metallic square patch. To enhance the bandwidth of 1-bit reconfigurable reflectarray, we choose the central frequency at 5.0 GHz whose phase shift is 200° where the maximum phase shift occurs. Phase difference within 180°± 20° is realized from 4.7 GHz to 5.3 GHz. Utilizing this wideband element, the 12 × 12 reconfigurable reflectarray antenna is fabricated and measured. A control board which can display phase shift distributions in real-time is designed to regulate all PIN diodes independently. Experimental results show that beam-scanning within ±50° can be achieved both in xoz- and yoz-plane at 5.0 GHz. Also, the measured results present that -1dB gain bandwidth is 8.4% from 4.85 GHz to 5.275 GHz.
12 February 2020 in IEEE Journal on Emerging and Selected Topics in Circuits and Systems
Verified
Journal Article
Closed access
JHJiaqi Han
Jiaqi Han
Long LiLong Li
Long Li
STShuncheng Tian
Shuncheng Tian
GLGuangyao Liu
Guangyao Liu
HLHaixia Liu
Haixia Liu
YSYan Shi
Yan Shi
In this paper, a comprehensive study of millimeter-wave (mmW) imaging for far-field and near-field objects using 1-bit programmable metasurface (PMS) is presented. Theoretical PMS imaging simulation models are proposed by using plane-wave angular spectrum approach, in which two simulation models based on the flexible mmW beam-forming of PMS are developed. The first imaging model steers the high-gain beams electronically to scan over the region of interest, which is suitable for far-field object detection and surveillance. In the second model, randomly complex beams are generated that can sample the target objects in time domain, which is suitable for Fresnel region imaging. Physical optics theory is employed in the two imaging models for calculating reflected waves. Then, a 1-bit 20 × 20 PMS imager operating at 35 GHz is designed. The PMS imager is composed of a PIN-diode-loaded metasurface and a control board with 400 output channels. Finally, we measure 64 groups of randomly distributed fields using the planar near-field scanning technique in the anechoic chamber. Through imaging reconstruction, it is verified that the proposed PMS is a promising technique for mmW imaging with excellent performance.
1 September 2016 in Optical Materials Express
Verified
Journal Article
Open access
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YZYing Zhang
Ying Zhang
YSYan Shi
Yan Shi
CLChang-Hong Liang
Chang-Hong Liang
This paper proposes a graphene-based broadband tunable absorber with over 90% absorption and is polarization insensitive at mid-infrared frequencies. The proposed absorber consists of a periodic array of a dual electric LC (ELC) metamaterial unit fabricated on a multilayer structure composed of Au/BaF2/graphene materials from the bottom to the top. In the proposed structure, interaction between the dual ELC unit and the graphene sheet generates three close resonant frequencies, thus leading to a broadband absorption from 25.08THz to 39.56THz. By varying graphene’s chemical potential, wide absorption bandwidth can be flexibly tuned. Due to the approximate symmetry of the structure, the proposed absorber demonstrates polarization-insensitive and wide-angle characteristics. Simulation results demonstrate that the absorption efficiency of the proposed structure can be as high as more than 90% from 25.08 THz to 44.81THz with variation of the graphene’s chemical potential from 0.2eV to 0.8eV.
9 August 2019 in IEEE Access
Verified
Journal Article
Open access
PZPei Zhang
Pei Zhang
Long LiLong Li
Long Li
XZXuanming Zhang
Xuanming Zhang
HLHaixia Liu
Haixia Liu
YSYan Shi
Yan Shi
A new design of dual-polarization and multi-focus near-field focusing (NFF) reflective metasurface for wireless power transfer (WPT) system is proposed in this paper. In terms of multi-beam phase synthesis of reflective metasurface, the dual-polarization metasurface with independent regulation characteristics is introduced to realize multi-focus and high-efficiency WPT. The single-feed single-focus and the single-feed dual-focus metasurface working at X-band (10 GHz) with $26\times 26$ elements in two polarizations are designed, fabricated and measured by planar near-field scanning experiments. Furthermore, a compact antenna is designed and fabricated as the receiver to form a practical WPT system. The measurement results show that a NFF transfer system is 15 dB higher than a non-NFF transfer system. Through full-wave simulation and experiments of three cases, single focus, dual-focus, and single focus with dual-polarization can respectively realize the maximum focusing efficiency of 71.6%, 68.3% and 65.9%. The relative bandwidth with 50% power focusing efficiency of these three cases are all about 12%, which demonstrates the stability and feasibility of the NFF reflective metasurface for practical WPT applications.
29 November 2022 in IEEE Transactions on Microwave Theory and Techniques
Verified
Journal Article
Closed access
DXDexiao Xia
Dexiao Xia
XWXin Wang
Xin Wang
JHJiaqi Han
Jiaqi Han
HXHao Xue
Hao Xue
GLGongxu Liu
Gongxu Liu
TCTie Jun Cui
Tie Jun Cui
A novel direction of arrival (DoA) estimation method based on amplifier-integrated active metasurface is proposed to find multisource directions by a single-channel system. Nonuniformly periodic time modulation (NPTM) on the metasurface reduces the hardware complexity by taking full advantage of the spectral resources. As a result, only partial metasurface elements are required to achieve 2-D DoA estimation, while the remaining elements can be redesigned and encoded to control electromagnetic waves. Thus, adaptive beamsteering can be expected to realize in a full-duplex way. Moreover, the amplifiers in the metasurface can function as modulation units to generate the required harmonics and enhance signal quality. The nonideality of the modulated square wave due to the active devices is allowed without affecting the estimation accuracy. An active metasurface prototype composed of 5 $\times$ 5 elements is fabricated and measured in the microwave anechoic chamber for multisource direction finding. The measured maximum error is 0.31 $^{\circ}$ , which is high accuracy compared with the state-of-the-art works. Thus, the proposed method has application values in the Internet of Things (IoT), wireless communications, and radar.
15 August 2017 in IEEE Access
Verified
Journal Article
Open access
YSYan Shi
Yan Shi
YZYing Zhang
Ying Zhang
In this paper, a wideband tunable reflectarray consisting of a graphene-based metamaterial structure has been developed to generate an orbital angular momentum (OAM) vortex wave in terahertz. In the proposed reflectarray, a multi-layer graphene metamaterial unit cell is designed, and through varying chemical potentials of the graphene sheets, reflection phase range of 360° and reflection magnitude better than -2.5 dB can be achieved. By suitably choosing the chemical potentials of the graphene layers, the designed reflectarray can produce the OAM vortex waves with l = ±1, ±2, and ±3 modes. Moreover, the OAM beams operating in a wide frequency band from 1.8 to 2.8 THz can be generated with the adjustment of the chemical potentials. Simulation results demonstrate good performance of the proposed reflectarray in the efficient generation and manipulation of the OAM vortex waves, which is promising to be used in wireless communication.