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Revisit to Mutual Coupling Effects on Multi-Antenna Systems

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Journal of Communications and Information Networks 2020年第4期5卷 411-422页

作者： Xiaoming Chen Huiling Pei Mengting Li Huilin Huang Quanxin Ren Qi Wu anxue zhang Ahmed A.Kishk School of Information and Communications Engineering Xi’an Jiaotong UniversityXi’an 710049China Faculty of School of Electronics and Information Engineering Beihang UniversityBeijing 100191China Department of Electrical and Computer Engineering Concordia UniversityMontrealH3G 1M8Canada

Due to space limitation,mutual coupling occurs almost invisibly in array *** this paper,the mutual coupling effects on the two most popular categories of array antennas,i.e.,phased arrays and multiple-input multiple-output(MIMO)antennas,are *** misconceptions regarding the mutual coupling effects are *** is shown that the steering pattern of a phased array at an arbitrary scan-ning angle can be readily calculated once the embedded radiation patterns of the array elements(including the mutual coupling effect)are *** antenna spacing decreases,absorption loss increases,yet the phase terms tend to add up constructively as antenna spacing reduces,which may overcompensate the absorption loss due to mutual ***,the array efficiency may be increased by reducing the antenna spacing.A patch antenna array is used to illustrate this *** is further shown that while mutual coupling tends to reduce the correlation of two-element arrays,it has a negligible effect on the overall correlations of larger ***,various mutual coupling reduction techniques are briefly *** feasible techniques for large planar arrays are used to illustrate the benefits of array decoupling.

关键词： correlation diversity measure MIMO an-tenna mutual coupling phased array

Cross-polarization suppression in C-shaped microstrip patch antenna employing anisotropic dielectrics

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Journal of Advanced Dielectrics 2017年第4期7卷 29-33页

作者： Hongyu Shi Shitao Zhu Jianxing Li anxue zhang Zhuo Xu School of Electronic and Information Engineering Xi'an Jiaotong University Xi'anShaanxi 710049P.R.China Electronic Materials Research Laboratory and the Key Laboratory of the Ministry of Education Xi'an Jiaotong University Xi'anShaanxi 710049P.R.China

An anisotropic dielectric realized by layered ceramic structures was adopted to design a low cross-polarization C-shaped patch *** anisotropic dielectric performs as a substrate and can cause additional cross-polarized fields which are able to cancel the cross-polarized fields generated by the C-shaped patch itself,and then reduce the cross-polarization *** to the C-shaped patch antenna with an isotropic substrate,the cross-polarization of the proposed antenna is suppressed by more than 15 dB with a little gain enhancement at 2.4 *** anisotropic dielectric has a little impact on the direction of the C-shaped patch *** gain of the proposed C-shaped patch antenna is 6.8 dB with a cross-polarization of28 dB.

关键词： Anisotropic dielectrics layered ceramic structures low cross-polarization patch antennas

An Efficient Method to Reduce the Numerical Dispersion in the HIE-FDTD Scheme

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Wireless Engineering and Technology 2011年第1期2卷 30-36页

作者： Juan Chen anxue zhang 不详

A parameter optimized approach for reducing the numerical dispersion of the 3-D hybrid implicit-explicit finite-difference time-domain (HIE-FDTD) is presented in this letter. By adding a parameter into the HIE-FDTD formulas, the error of the numerical phase velocity can be controlled, causing the numerical dispersion to decrease significantly. The numerical stability and dispersion relation are presented analytically, and numerical experiments are given to substantiate the proposed method.

关键词： HIE-FDTD Numerical Dispersion Weakly Conditionally Stability

Anisotropic impedance holographic metasurface for near-field imaging

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Photonics Research 2024年第10期12卷 2226-2234页

作者： XIANGSHUAI MENG HAOYU zhang TAO WU YU LI anxue zhang LEI RAN XIAOMING CHEN School of Information and Communications Engineering Xi’an Jiaotong UniversityXi’an 710049China Xi’an Institute of Space Radio Technology Xi’an 710199China National Key Laboratory of Radar Signal Processing Xidian UniversityXi’an 710071China

In this paper,the concept of anisotropic impedance holographic metasurface is proposed and validated by realizing holographic imaging with multipoint focusing techniques in near-field areas at the radio frequency *** the microwave holographic leaky-wave theory and near-field focusing principle,the mapped geometrical patterns can be constructed based on the correspondence between meta-atom structural parameters and equivalent scalar impedances in this modulated *** from conventional space-wave modulated holographic imaging metasurfaces,this surface-wave-based holographic metasurface fed by monopole antenna embedded back on metal ground enables elimination of the misalignment error between the air feeding and space-wave-based metasurface and increase of the integration performance,which characterizes ultra-low profile,low cost,and easy *** core innovation of this paper is to use the classical anisotropic equivalent surface impedance method to achieve the near-field imaging effect for the first *** on this emerging technique,a surface-wave meta-hologram is designed and verified through simulations and experimental measurements,which offers a promising choice for microwave imaging,information processing,and holographic data storage.

关键词： surface holographic impedance

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Transformation of a metasurface on the substrate interface into the same metasurface in a homogenized substrate based on two kinds of modified Babinet's principles

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Science China(Information Sciences) 2023年第12期66卷 238-250页

作者： Xiaobo LIU Rui LU anxue zhang Qiang CHENG Xiaoming CHEN School of Information and Communications Engineering Xi'an Jiaotong University School of Mathematics and Statistics Xi'an Jiaotong University State Key Laboratory of Millimeter Waves and School of Electrical Engineering Southeast University

Previously, the metasurface was usually manufactured on a dielectric substrate using the printed circuit boards（PCB） technology. However, due to the existence of the substrate interface, the electromagnetic radiation and coupling of the sub-wavelength metasurface becomes more complex for theoretical analysis. To this end, an indirect method is developed to transform the problem of a metasurface in a dielectric half-space into a simpler problem of the same metasurface in a homogenized dielectric space. Specifically, two different theoretical models of complementary metasurfaces in a dielectric half-space are first given. A specific yet unknown relative permittivity is included in one model to realize the above transformation. By comparing these two theoretical models in terms of the surface impedance matrix, the specific yet unknown relative permittivity is analytically derived as (εr,unk)1/2=(εr,1)1/2/2 +(εr,2)1/2/2. Finally, two arbitrary metasurfaces are given to verify the proposed theory for arbitrary incidence wave in dielectric half-space. The theory can greatly simplify the analysis and design of the metasurface in a dielectric halfspace, because only the metasurface in a homogenized dielectric space like vacuum needs to be theoretically solved after completing the above transformation.

关键词： dielectric half-space homogenized dielectric space metasurface relative permittivity surface impedance matrix substrate interface

Wideband polarization-independent anomalous reflection metasurface with multiple resonance modes

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Journal of Advanced Dielectrics 2017年第2期7卷 17-20页

作者： Guoxiang Dong Song Xia Yongyong Zhuang Hongyu Shi Zhan zhang Yuchen He anxue zhang Xiaoyong Wei Zhuo Xu Electronic Materials Research Laboratory Key Laboratory of the Ministry of Education&International Center for Dielectric Research Xi'an Jiaotong University Xi'anShaanxi 710049P.R.China School of Electronic and Information Engineering Xi'an Jiaotong University Xi'an Shaanxi 710049P.R.China Zhonghang Electronic Measuring Instruments Co. Ltd Xi'anShaanxi 710049P.R.China

An ultra-thin metasurface is proposed to realize wideband polarization-independent anomalous reflection. The sub-wavelengthresonator can produce different resonance modes, which are the result of the combined effect of dielectric and the metallic *** gradient metasurface is done by six discrete orientation of the local sub-wavelength resonator which provides a phase *** simulation and measured results show that 9 GHz bandwidth of the anomalous reflection is achieved.

关键词： Metasurface anomalous reflection polarization

On the uniqueness of virtual substrate for metasurface in a dielectric half-space

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Science China(Information Sciences) 2022年第1期65卷 207-217页

作者： Xiaobo LIU Wei XUE Xiaoming CHEN anxue zhang Qiang CHENG Zongben XU School of Information and Communications Engineering Xi'an Jiaotong University School of Mathematics and Statistics Xi'an Jiaotong University State Key Laboratory of Millimeter Waves and School of Electrical Engineering Southeast University

In this paper, we study the uniqueness of a virtual substrate for periodic metallic elements in a dielectric half-space. When the periodic metallic elements are placed at the interface of different substrates,they can be regarded to be embedded into a virtual substrate whose thickness approaches zero. However,the process of the mathematical limit of the thickness seems to be independent of the choice of the virtual substrate. Thereby, it is necessary to verify whether the arbitrary virtual substrate holds for the case. It is theoretically verified that the permittivity of the virtual substrate should be unique in order to satisfy the physical boundary condition of the periodic metallic elements. The root of the phenomenon is that the mathematical limit gives the alternative means to approach the actual physical situation, but the actual physical situation determines the way how the mathematical limit approaches zero. Finally, for comparison,two different virtual substrates are designed to validate the theory, for alternative substrate, incidence angle,and metallic elements. Besides, the finding can also be used to simplify the analysis and design of the metasurface by converting the periodic metallic elements in a dielectric half-space to the same periodic metallic elements in a uniform substrate.

关键词： virtual substrate periodic metallic elements mathematical limit relative permittivity boundary condition

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Polarization singularities in planar electromagnetic resonators with rotation and mirror symmetries

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Photonics Research 2023年第6期11卷 936-952页

作者： JIE YANG XUEZHI ZHENG JIAFU WANG anxue zhang TIE JUN CUI GUY A.E.VANDENBOSCH WaveCoRE Research Group KU LeuvenLeuven B-3001Belgium Xi’an Jiaotong University Xi’an 710049China State Key Laboratory of Millimeter Wave Southeast UniversityNanjing 210096China

In this work,we apply the group representation theory to systematically study polarization singularities in the inplane components of the electric fields supported by a planar electromagnetic(EM)resonator with generic rotation and reflection *** reveal the intrinsic connections between the symmetries and the topological features,i.e.,the spatial configuration of the in-plane fields and the associated polarization *** connections are substantiated by a simple relation that links the topological charges of the singularities and the symmetries of the *** verify,a microwave planar resonator with the D8group symmetries is designed and numerically simulated,which demonstrates the theoretical findings *** discussions can be applied to generic EM resonators working in a wide EM spectrum,such as circular antenna arrays,microring resonators,and photonic quasi-crystals,and provide a unique symmetry perspective on many effects in singular optics and topological photonics.

关键词： planar rotation symmetries

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一种超材料的平面型频率选择反射面特性研究

电波科学学报 2015年第1期30卷 109-113页

作者：朱安福向坤张安学华北水利水电大学电力学院河南郑州450011 西安交通大学电子与信息工程学院陕西西安710049

为降低频率选择反射面的设计维度和制造成本,研究了开口谐振环的结构尺寸对谐振点的影响,提出了一种双面印制型开口谐振环(Split-Ring Resonators,SRR)结构.利用负磁导率超材料,设计了一种双面印制型SRR结构,在平面内对SRR正交排列形成... 详细信息

为降低频率选择反射面的设计维度和制造成本,研究了开口谐振环的结构尺寸对谐振点的影响,提出了一种双面印制型开口谐振环(Split-Ring Resonators,SRR)结构.利用负磁导率超材料,设计了一种双面印制型SRR结构,在平面内对SRR正交排列形成双面印制型频率选择反射面,对馈源频段的垂直极化波反射,而对其它频段来波透射.通过对新型频率选择反射面的测试,测试结果表明符合设计频率选择反射面(Frequency Selective Reflector,FSR)的反射性能.

关键词：开口谐振环频率选择反射面谐振点超材料

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