This paper uses a Computer Simulation Technology microwave studio to simulate the performance of a new highdirectivity anisotropic magnetic metamaterial antenna loaded with a frequency-selective surface. Frequency-sel...This paper uses a Computer Simulation Technology microwave studio to simulate the performance of a new highdirectivity anisotropic magnetic metamaterial antenna loaded with a frequency-selective surface. Frequency-selective surface with cross-dipole element has a great effect on the directivity, radiation pattern, and gain of such an antenna. The experimental results show that frequency-selective surface （FSS） significantly improve the radiation performance of anisotropic magnetic metamaterial antenna. For example, as a single anisotropic magnetic metamaterial antenna, half power beam width is 4 degrees in the H planes, and the gain of this antenna is 19.5dBi at 10CHz, achieving a 2.1 degree increment in half power beam width, and a 7.3 dB gain increment by loading with the FSS reflector. The simulating results are consistent with our experimental results.展开更多
By applying meander-line for electrical loss and magnetic material for magnetic loss,we present a metamaterial absorber which is wide-spaced and dual-band(1.35—2.24 GHz and 10.37—12.37 GHz).The novelty of this study...By applying meander-line for electrical loss and magnetic material for magnetic loss,we present a metamaterial absorber which is wide-spaced and dual-band(1.35—2.24 GHz and 10.37—12.37 GHz).The novelty of this study mainly lies in a combination of two kinds of losses to consume electromagnetic energy,which can get better dual-band absorption.In the electrical loss layer,meander-line structures are printed on both surfaces of the substrate and the structure series with resistors.Considering the need for miniaturization,we connect eight metallic vias with these meander-line areas to form a compact 2.5-dimensional(2.5D)structure.The dimension of the unit cell is miniaturized to be 5.94 mm×5.94 mm,about 0.035λat the center frequency of the lower absorption band.In the magnetic loss layer,the 0.4 mm thick magnetic material is employed on a metallic ground plane.In addition,the complex permittivity and complex permeability of the magnetic material are given.Finally,we fabricate a prototype of the proposed absorber and obtain a measurement result which is in good agreement with the full-wave simulation result.展开更多
提出了一种新型的紧凑型交互嵌入式人工磁导体（IE—AMC：inter—embedded artificial magnetic conductor）结构。用有限元方法分析了其反射相位特性及表面波传输特性。结果表明，对于同样的单元尺寸，这种结构可以使AMC结构的谐振频...提出了一种新型的紧凑型交互嵌入式人工磁导体（IE—AMC：inter—embedded artificial magnetic conductor）结构。用有限元方法分析了其反射相位特性及表面波传输特性。结果表明，对于同样的单元尺寸，这种结构可以使AMC结构的谐振频率降低超过70％。换句话说，设计具有同样谐振频率的AMC结构单元，使用这种结构的单元尺寸仅为普通结构的30～40％左右。这使得仅用双层结构就可以实现可用于低频无线通信波段的AMC结构。同时在实际的微波集成电路及天线阵应用中，有限的空间内可以使用更多的AMC结构单元，从而使电路及天线阵的性能得到更大的提高。展开更多
Artificial visual systems can recognize desired objects and information from complex environments, and are therefore highly desired for pattern recognition, object detection, and imaging applications. However, state-o...Artificial visual systems can recognize desired objects and information from complex environments, and are therefore highly desired for pattern recognition, object detection, and imaging applications. However, state-of-the-art artificial visual systems with high recognition performances that typically consist of electronic devices face the challenges of requiring huge storage space and high power consumption owing to redundant data. Here, we report a terahertz(THz) frequency-selective surface using a graphene split-ring resonator driven by ferroelectric polarization for efficient visual system applications. The downward polarization of the ferroelectric material offers an ultrahigh electrostatic field for doping p-type graphene with an anticipated Fermi level. By optimizing the geometric parameters of the devices and modulating the carrier behaviors of graphene, our plasmonic devices exhibit a tunable spectral response in a range of 1.7–6.0 THz with continuous transmission values. The alloptical neural network using graphene plasmonic surfaces designed in this study exhibited excellent performance in visual preprocessing and convolutional filtering and achieved an ultrahigh recognition accuracy of up to 99.3% in training the Modified National Institute of Standards and Technology(MNIST) handwritten digit dataset. These features demonstrate the great potential of graphene plasmonic devices for future smart artificial vision systems.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 60371010)
文摘This paper uses a Computer Simulation Technology microwave studio to simulate the performance of a new highdirectivity anisotropic magnetic metamaterial antenna loaded with a frequency-selective surface. Frequency-selective surface with cross-dipole element has a great effect on the directivity, radiation pattern, and gain of such an antenna. The experimental results show that frequency-selective surface （FSS） significantly improve the radiation performance of anisotropic magnetic metamaterial antenna. For example, as a single anisotropic magnetic metamaterial antenna, half power beam width is 4 degrees in the H planes, and the gain of this antenna is 19.5dBi at 10CHz, achieving a 2.1 degree increment in half power beam width, and a 7.3 dB gain increment by loading with the FSS reflector. The simulating results are consistent with our experimental results.
文摘By applying meander-line for electrical loss and magnetic material for magnetic loss,we present a metamaterial absorber which is wide-spaced and dual-band(1.35—2.24 GHz and 10.37—12.37 GHz).The novelty of this study mainly lies in a combination of two kinds of losses to consume electromagnetic energy,which can get better dual-band absorption.In the electrical loss layer,meander-line structures are printed on both surfaces of the substrate and the structure series with resistors.Considering the need for miniaturization,we connect eight metallic vias with these meander-line areas to form a compact 2.5-dimensional(2.5D)structure.The dimension of the unit cell is miniaturized to be 5.94 mm×5.94 mm,about 0.035λat the center frequency of the lower absorption band.In the magnetic loss layer,the 0.4 mm thick magnetic material is employed on a metallic ground plane.In addition,the complex permittivity and complex permeability of the magnetic material are given.Finally,we fabricate a prototype of the proposed absorber and obtain a measurement result which is in good agreement with the full-wave simulation result.
文摘提出了一种新型的紧凑型交互嵌入式人工磁导体（IE—AMC：inter—embedded artificial magnetic conductor）结构。用有限元方法分析了其反射相位特性及表面波传输特性。结果表明，对于同样的单元尺寸，这种结构可以使AMC结构的谐振频率降低超过70％。换句话说，设计具有同样谐振频率的AMC结构单元，使用这种结构的单元尺寸仅为普通结构的30～40％左右。这使得仅用双层结构就可以实现可用于低频无线通信波段的AMC结构。同时在实际的微波集成电路及天线阵应用中，有限的空间内可以使用更多的AMC结构单元，从而使电路及天线阵的性能得到更大的提高。
基金supported by the National Natural Science Foundation of China(Grant No. 62201096)the Engineering Research Center of Digital Imaging and Display, Ministry of Education, Soochow University(Grant No. SDGC2246)the Open Project Program of Shanxi Key Laboratory of Advanced Semiconductor Optoelectronic Devices and Integrated Systems(Grant No. 2023SZKF12)。
文摘Artificial visual systems can recognize desired objects and information from complex environments, and are therefore highly desired for pattern recognition, object detection, and imaging applications. However, state-of-the-art artificial visual systems with high recognition performances that typically consist of electronic devices face the challenges of requiring huge storage space and high power consumption owing to redundant data. Here, we report a terahertz(THz) frequency-selective surface using a graphene split-ring resonator driven by ferroelectric polarization for efficient visual system applications. The downward polarization of the ferroelectric material offers an ultrahigh electrostatic field for doping p-type graphene with an anticipated Fermi level. By optimizing the geometric parameters of the devices and modulating the carrier behaviors of graphene, our plasmonic devices exhibit a tunable spectral response in a range of 1.7–6.0 THz with continuous transmission values. The alloptical neural network using graphene plasmonic surfaces designed in this study exhibited excellent performance in visual preprocessing and convolutional filtering and achieved an ultrahigh recognition accuracy of up to 99.3% in training the Modified National Institute of Standards and Technology(MNIST) handwritten digit dataset. These features demonstrate the great potential of graphene plasmonic devices for future smart artificial vision systems.
