双层EBG结构的优化设计

研究了一种新型的双层电磁带隙(EBG)结构,该结构在金属导带上刻蚀蝶形单元,在接地板上刻蚀圆环孔,并运用粒子群优化算法(PSO)与高频电磁仿真软件(HFSS)相结合的方法对接地板刻蚀圆孔进行优化,使结构的传输特性更好.在优化过程中,首先对圆孔的外径进行优化,然后在此基础上再优化内径,通过仿真计算结果可看出,优化后-10 dB的相对带宽和阻带的衰减值分别增加了22.69％和15.26％,通带波纹减小了76.76％.优化后结构的频率特性较好,优化效果理想.     

一种低通带波纹的EBG带阻滤波器

分析了串联加载的电磁带隙结构(EBG)带阻滤波器的通带波纹,比较了电容、电感和并联谐振加载的影响,设计和制作了一种低通带波纹的EBG带阻滤波器。该结构共有4个周期,通过在微带线的接地面上蚀刻螺旋形结构来实现。滤波器的中心频率为2.44GHz,阻带中心衰减大于50dB,相邻通带内的波纹小于0.29dB。仿真结果与试验结果相吻合,说明了分析和设计的正确性。     

一种蝶形单元的电磁带隙结构的频率特性

电磁带隙结构是光子晶体中的一种,它可以广泛地应用于微波、毫米波波段.研究了一种具有蝶形单元的电磁带隙结构,通过理论分析获得它的ABCD矩阵,将ABCD矩阵转换为散射矩阵,进而得到该结构的频率特性.在这种电磁带隙结构中引入缺陷,采用同样的分析方法获得它的频率特性.通过仿真计算可以看出,具有蝶形单元的电磁带隙结构大约有2.8 GHz带宽的阻带,相对带宽为52%;而具有缺陷的电磁带隙结构在阻带中形成一个具有一定带宽的通带,且通带的频率很容易调整.     

螺旋地板式电磁带隙结构的传输特性分析

为了实现电磁带隙结构(Electromagnetic Band Gap,EBG)的小型化,提出了一种螺旋地板式电磁带隙结构,即通过在接地金属板上加载螺旋结构的方法来减小谐振频率,实现EBG单元结构的小型化,并用HFSS软件建立结构仿真模型,分析了螺旋线单元长度变化对电磁带隙特性的影响规律。结果表明增加螺旋线单元长度可以使频率带隙向低频方向移动。最后,将地平面加载与未加载螺旋结构的两种EBG进行仿真分析。结果表明,螺旋地板式EBG能够抑制更低频段的电磁波,达到了EBG单元结构小型化的目的。     

EBG对圆波导介质棒相控阵扫描特性的改善

将电磁带隙(EBG)结构应用到圆波导介质棒相控阵列中,利用EBG结构所具有的表面波带隙特性有效消除了相控阵中的扫描盲区.比较了无限阵列的扫描特性和有限阵列中心单元方向图在EBG加载前后的变化.仿真分析表明,以EBG结构作为圆波导介质棒相控阵的地平面,能有效消除扫描盲区,扩展扫描范围.     

基于U型双平面电磁带隙结构的小型化低通滤波器

提出了新型的微波低通滤波器结构,利用人工电磁谐振结构的基本特性,当谐振单元的结构尺寸满足一定条件时,会产生带隙特性,阻带的频率宽度和抑制深度随着谐振器的阶数而变化,由此也会增大电路的结构尺寸。为了改善电磁带隙结构的频率响应特性,将周期性谐振单元在基板两侧对称分布,并通过在传输线上添加开路枝节谐振器和马刺线结构来增加传输零点,从而增大阻带频率宽度和带内抑制深度。同时,将渐变理论应用于电磁带隙结构以改善通带波纹系数。与传统电磁带隙结构相比,所设计的改进型电磁带隙结构既可以改善频域传输特性,又可以减小电路尺寸。     

一种新型紧凑电磁带隙结构

设计了一种新型叉状电磁带隙结构(简称EBG)。该型EBG结构与传统的蘑菇状EBG结构相比尺寸减小近40%。在不改变周期的情况下,通过调整伸长窄带长度可以改变带隙特性频率。测量结果显示,新型EBG结构在宽频带内具有良好的阻带特性。用在微波集成电路中,可以减小电路尺寸和抑制阻带内波纹。     

刻蚀在导带边缘的PBG微带线

首次提出了一种新型的50Ω光子带隙(PBG)结构微带线。该PBG结构的制作是在金属导带边缘周期地刻蚀矩形和梯形结构,其微带线的阻带较深、较宽,且通带的波纹较小,与在金属导带或金属接地板上刻蚀周期性孔的通常PBG微带线相比,该新型PBG结构微带线的S参数特性较好。这种新型PBG结构的仿真结果得到了实验的证实。     

EBG结构磁性材料微带天线的研究与设计

以磁性材料(JV-5)作为基板,设计双L型结构的微带天线,带宽是普通基板的2倍以上,尺寸缩小了40%。在此基础上引入电磁带隙(EBG)结构,设计了一种基于磁性基板EBG结构的微带天线,该EBG结构采用接地板腐蚀性,即在地板上腐蚀出周期H型和圆形结构,采用电磁仿真软件HFSS14.0进行仿真设计。结果显示,与非磁性材料做基板的微带天线相比,EBG结构磁性材料具有小型化和宽频化突出优点,相对带宽达到10%以上,增益方面略有降低,引入EBG结构后能在一定程度上减小了天线的尺寸同时增大了天线的带宽,改善了天线的增益和辐射特性。     

EBG结构磁性材料微带天线的研究与设计

以磁性材料(JV-5)作为基板,设计双L型结构的微带天线,带宽是普通基板的2倍以上,尺寸缩小了40%。在此基础上引入电磁带隙(EBG)结构,设计了一种基于磁性基板EBG结构的微带天线,该EBG结构采用接地板腐蚀性,即在地板上腐蚀出周期H型和圆形结构,采用电磁仿真软件HFSS14.0进行仿真设计。结果显示,与非磁性材料做基板的微带天线相比,EBG结构磁性材料具有小型化和宽频化突出优点,相对带宽达到10%以上,增益方面略有降低,引入EBG结构后能在一定程度上减小了天线的尺寸同时增大了天线的带宽,改善了天线的增益和辐射特性。     

A novel periodic electromagnetic bandgap structure for finite-widthconductor-backed coplanar waveguides

The one-dimensional (1-D) periodic electromagnetic bandgap (EBG) structure for the finite-width conductor-backed coplanar waveguide (FW-CBCPW) is proposed. Unlike the conventional EBG structures for the microstrip line and the coplanar waveguide (CPW), which are typically placed on one of the signal strips and the ground plane, this EBG cell is etched on both the signal strip and the upper ground plane of FW-CBCPW resulting in a novel circuit element. The equivalent circuit is also used to model the EBG cell. Measured and full-wave simulated results show that the cell exhibits remarkable stopband effect. The low-pass filter with lower cutoff frequency and wider rejection bandwidth is constructed from a serial connection of the EBG cells. The effect of back metallization on the guiding characteristic is also discussed. Compared to the published EBG cells, the proposed structure has the advantages of relative flexibility, higher compactness, lower radiation loss, and easier integration with the uniplanar circuits     

Cavity resonance suppression in power delivery systems using electromagnetic band gap structures

The utilization of electromagnetic band gap (EBG) structures is a new and promising approach in plane pair noise cavity resonance suppression. In this paper, EBG/plane pair structures are studied with full-wave methods and results are experimentally verified. A new equivalent circuit modeling approach of characterizing the frequency behavior of the entire EBG/plane pair structure is presented. The equivalent circuit of the unit cell is proposed and the procedure to extract circuit parameters is described. The influence of EBG patch parameters on the band gap characteristics is quantified and the results provide some design rules to circuit designers. Examples of applications of EBG structures to power/ground plane noise suppression are given.     

Microwave Bandstop Filters Using Novel Artificial Periodic Substrate Electromagnetic Band Gap Structures

Novel microwave and millimeterwave (mm-wave) bandstop filters using artificial periodic substrate electromagnetic bandgap (EBG) are investigated in this paper. Three types of microstrip structures using periodically modified trace width, patterned dielectric substrate, and periodically modified ground plane are treated, respectively. By periodically modifying either the width of the conductor trace, the substrate height, or the dielectric constant of a standard microstrip transmission line, it has been possible to design microwave bandstop filter functions with wide stopband characteristics and reduced size, compared to conventional microwave/RF filter structures. Commercial electronic design automation (EDA) and computational electromagnetic tools such as Agilent's advanced design system (ADS) and CST Microwave Studio are used in the design and simulations of these filter structures. The effects of the physical parameters of the structures on the filter characteristic are studied. The design procedure and simulation results are described and possible applications of these filter structures are discussed in this paper. A particularly wide stopband is achieved by the circuits presented in this paper, which use only a few cell elements. A significant performance improvement of microstrip patch antenna has been observed by implementing one of the presented EBG periodic substrate structures.      

High Aspect-Ratio Coplanar Waveguide Wideband Bandpass Filter With Compact Unit Cells

This paper introduces a micromachined thick single-metal-layer high aspect-ratio coplanar waveguide (CPW) wideband bandpass filter with compact unit cells based on the electromagnetic bandgap (EBG) concept. The filter is miniaturized as a result of using the EBG concept in design, and also by realizing high aspect-ratio structures with polymer-based deep X-ray lithography fabrication. Cascaded unit cells in the EBG model consist of capacitive and inductive parallel periodically loaded transmission lines, which determine the filter bandwidth. Compact unit cells are realized by using high aspect-ratio CPW stepped-impedance resonators. The main advantage of this approach is that the high aspect-ratio CPW structures make short unit cells practically realizable, resulting in a compact filter structure. A bandpass filter with 47% bandwidth is designed and fabricated using deep X-ray lithography, and the performance and physical size is compared to a conventional quarter-wavelength-based admittance inverter filter.      

微波光子晶体的相位特性研究

为了实现微波光子晶体结构的小型化,根据其等效电路分析模型,提出了三种不同结构的双层电磁带隙(EBG)结构,通过仿真得到三种不同结构EBG的反射曲线,并与传统的单层EBG结构进行仿真和比较,进而分析了各种双层EBG的电磁反射特性的特点。仿真结果表明:三种EBG结构均存在零位相反射,但其反射频率不相同。与单层同参数的EBG结构相比,两种加载金属地平面的双层EBG结构的零位相频率点向高频移动,而未加载地平面结构的双层EBG结构所对应的零位相频率则向低频方向移动,该现象为小型化EBG单元结构提供了依据。     

EBG Superstrate Array Configuration for the WAAS Space Segment

Two different electromagnetic bandgap (EBG) superstrate array antenna configurations, intended for the Wide Area Augmentation Service space segment, are presented in this paper. The described antenna configurations take advantage of the directivity enhancement produced by a semireflective sheet placed parallel to a metallic ground plane. The first design presented is realized using a 2$,times,$ 2 circularly polarized (CP) patch array illuminating an EBG superstrate composed of a square pattern of circular holes etched in a thin metallic sheet. The second design consists of a 2$,times,$ 2 CP helix array feeding a hexagonal pattern of holes etched into a metallic EBG superstrate. Both configurations have been designed, breadboarded, and measured, and excellent agreement between simulations and measurements has been recorded. The accurate control of the antenna pattern phase center variation with both the frequency and the antenna field of view, necessary for the intended navigation antenna application, has been the principal challenge of this work. The EBG technology designs presented here are simpler than conventional navigation antennas and can lead to cost reduction, beamforming network simplification, and height reduction while offering similar radio-frequency performances to equivalent products realized in conventional technology.      

Design of Novel Compact Electromagnetic Bandgap Structures with Enhanced Bandwidth

Two kinds of compact electromagnetic band gap （EBG） structures are designed. A two layer compact EBG structure configured with cross spiral shape line inductors and interdigital capacitors is first presented. Because of its significantly enlarged equivalent inductor and capacitance, the period of the lattice is approximately 4.5% of the free space wavelength. By insetting several narrow slits in the ground plane, the bandwidth of the main bandgap is enhanced by nearly 19%. Further effort has been made for designing a three layer compact EBG structure. Simulation results show that its period is reduced by about 26% compared to that of proposed two layer EBG structure, and the bandwidth of the main bandgap is about 3 times as that of the proposed two layer EBG structure. The detailed designs including a two layer compact 3×7 EBG array with and without defect ground plane and the three layer EBG array are given and simulation results are presented.     

EBG-based dual mode resonator filter

Periodic etched pattern on the ground plane underneath the ring resonator are incorporated to realize a miniaturized ring filter with stronger rejection of higher harmonic passbands. Two square microstrip ring filters, with and without periodic etched pattern on the ground plane, were designed with a bandwidth of 135 MHz centered at 2.4 GHz and 3 GHz respectively. A rejection of at least 25 dB of the second harmonic passband has been achieved for the filter with periodic etched pattern.