采用渐变尺寸的DGS结构的设计

在原有周期DGS(Defected Ground Structure)结构基础上,提出了一种周期渐变尺寸的DGS结构,比原有结构具有更好的阻带特性。并将其应用于毫米波微带通滤波器的设计,改善了阻带性能。对DGS结构的等效电路作了分析,与原有DGS结构仿真的比较,结果证明了优化的渐变尺寸DGS结构能有效地改善带阻特性,同时对通带内插入损耗的影响较小。     

一种新型CPW滤波器的设计

设计了一种新型结构的CPWDGS单元,这种DGS结构在CPW两侧的接地面上对称刻蚀一定形状,形成带阻特性。通过对DGS结构单元的适当组合可以实现宽阻带的微波滤波器,仿真结果表明,该结构具有陡峭的阻带衰减特性,通过改变DGS单元的尺寸可以工作于不同的频段,增加单元数目可以改善带阻滤波器的性能。设计制作了一个五单元的CPW带阻滤波器,测试结果与仿真结果相吻合。这种结构的带阻滤波器设计灵活,结构简单、易于制作、便于安装,具有广泛的应用前景。     

基于缺陷地抑制高阶谐波的带通滤波器设计

采用微带线设计的平行耦合滤波器(MCL-BPF)在通带以外往往产生谐波,出现寄生频段。利用缺陷地结构(Defected Ground Structure,DGS)的单极点带阻特性和慢波效应可以改善寄生通带,抑制谐波输出。对2.4GHz的传统微带平行耦合滤波器和改进型带通滤波器进行了仿真设计与加工测试。实测结果与仿真数据良好吻合,所提出基于斜哑铃型DGS的带通滤波器(S-DGS-BPF)可抑制至四阶谐波,抑制度达到-22dB以下,阻带为3-10GHz,中心频率处回波损耗为-26.93dB。并且改进型滤波器的尺寸缩小了约10%。     

基于C型DGS的双通带滤波器设计

基于环形谐振器的基础结构,提出了新型C型缺陷地结构(defected ground structure,DGS)的双通带滤波器。利用C型DGS结构的高阻抗传输线特性,通过调节C型DGS结构的长度与宽度尺寸,可以实现对双频段带通滤波器的工作频段控制。最后给出了一个2.4 GHz和3.45 GHz工作频段的微带双通带滤波器设计实例,其测试结果与仿真结果吻合。     

一种新颖的半圆形缺陷地结构微带线

本文提出了一种半圆缺陷地结构(Defected Ground Structure)微带线,该结构比传统的正方形DGS微带线有更好的带阻特性和等效Q值.本文分析了半圆DGS参数变化对带阻特性的影响,建立了该微带线的等效电路模型并提取参数;通过等效电路模型可以看出,半圆DGS微带线的Q值为45,大大优于传统DGS微带线的8.5.最后,本文设计了紧凑结构半圆DGS低通滤波器,由于半圆DGS微带线的高Q值,该滤波器的通带插入损耗小于0.2dB,其测试结果与仿真结果相当吻合,验证了所提结构的可靠性.     

基于DGS结构的超宽带高通滤波器设计

介绍目前应用于微波平面电路小型化领域的DGS结构,通过仿真试验研究了DGS结构对耦合微带双线的影响,基于仿真结果设计小型化、结构简单的超宽带高通滤波器,并制作实物进行测量,实测数据与仿真结果基本吻合。     

基于SGS的UWB滤波器设计

在传统哑铃型缺陷接地结构(defected ground structure,DGS)的基础上,提出了一种分割地结构(split ground structure),通过在传统哑铃型DGS上添加一条缝,形成了SGS结构,不仅有低通特性,而且产生了高通特性,即具有带通特性。借助于HFSS软件,比较了传统哑铃型DGS与SGS的仿真结果,分析了SGS结构参数变化对其频率特性的影响。并以此为基础设计了一种新颖的超宽带(UWB)带通滤波器,中心频率6.85 GHz,相对带宽110%,上边带20 dB阻带抑制达20 GHz。仿真结果表明,该滤波器具有较好的频率特性,说明基于SGS的UWB带通滤波器设计的有效性和可行性。     

加窗技术在微带EBG结构中的应用

研究了加窗技术在微带电磁带隙(EBG，Electromagnetic Band-Gap)结构中的应用，仿真结果表明加窗技术的应用可以有效地改善通带的平坦度，减小插损，对本文所研究的问题，3GHz以下的通带插损可以减小到0．4dB以内。制作了相应的实际电路，实验结果与仿真结果基本相符。     

一种新型一维周期DGS单元结构特性研究

该文设计了一种新型一维周期地面缺陷(Defected Ground Structure, DGS)单元结构,该DGS单元结构提高了等效电感。增加的等效电感可以容易控制DGS平面电路的截止频率特性。设计的周期DGS单元结构有非常好的截止和带阻特性。为了显示改进的等效电感,该文设计了3个周期相同而单元尺寸不同的DGS电路。DGS电路的测试结果显示截止和带阻的中心频率特性由该DGS单元结构的物理尺寸决定。     

带DGS结构的宽带微带线准椭圆函数滤波器设计

准椭圆滤波器体积小，重量轻，结构紧凑，比契比雪夫滤波器有更好的过渡特性，更高的带外抑制，在卫星通信和移动通信中有广泛的应用前景。但在用准椭圆滤波器实现宽带滤波器时，有时会遇到耦合间隙过小难以加工的问题。在准椭圆滤波器的谐振器底板加入缺陷接地结构（DGS），可以增强谐振器之间的耦合。应用DGS结构，用较宽的耦合间隙实现较强的耦合，从而使宽带滤波器物理上更容易实现。应用三维电磁场仿真软件，设计了一种带DGS结构的宽带微带线准椭圆函数滤波器。     

Quasi-elliptic filter characteristics of an asymmetric defected ground structure

An asymmetric defected ground structure (DGS) with respect to a microstrip line is proposed. Its unit cell consists of two square slots connected with a rectangular slot by meandered transverse slots. The simulated, measured and equivalent circuit responses have been presented. The unit DGS pattern under microstrip line produces wide rejection bandwidth and high sharpness factor. Its elliptic band-reject filter response is modelled by appropriate LC equivalent circuit. Two such DGS cells under a microstrip line produce 3-pole quasi-elliptic bandstop filter response, which shows deeper attenuation without appreciable change in pole frequencies in comparison to single cell structure. Unit DGS pattern under coupled gap microstrip lines produces band-accept filtering characteristics. The frequency characteristics show a quasi-elliptic highpass filtering characteristics with sharp lower transition knee. Accordingly, an LC equivalent circuit is proposed. A cascaded band-accept and band-reject filter is proposed for designing a wideband bandpass filter. The bandwidth and centre frequency of the bandpass filter can be varied by choosing different set of DGS dimensions.     

A design of the novel coupled-line bandpass filter using defectedground structure with wide stopband performance

In this paper, a novel three-pole coupled-line bandpass filter with a microstrip configuration is presented. Presented bandpass filters use defected ground structure (DGS) sections to simultaneously realize a resonator and an inverter. The proposed coupled-line bandpass filter provides compact size with low insertion-loss characteristic. Furthermore, a DGS shape for a microstrip line is newly proposed. The proposed DGS unit structure has a resonance characteristic in some frequency band. The proposed coupled-line filter can provide attenuation poles for wide stopband characteristic due to resonance characteristic of DGS. The equivalent circuit for the proposed DGS unit section is described. The equivalent-circuit parameters for DGS are extracted by using a three-dimensional finite-element-method calculation and simple circuit analysis method. A design method for the proposed coupled-line filter is derived based on coupled-line filter theory and the equivalent circuit of the DGS. The experimental results show excellent agreements with theoretical simulation results     

一种新颖的蝴蝶结形缺陷接地结构微带线

提出一种新颖的蝴蝶结形缺陷接地结构(DGS)微带线,分析了该微带线的带阻特性和慢波特性,同时考虑微带线损耗,建立了该微带线的等效电路模型及其参数提取,并分析了蝴蝶结形DGS结构变化对阻带特性的影响,最后将该DGS结构应用于紧凑结构低通滤波器的设计,模拟结果与实验结果吻合较好,验证了所提结构的可靠性。     

An asymmetric defected ground structure with elliptical response and its application as a lowpass filter

A new asymmetric defected ground structure (DGS) consisting of two square headed slots connected with a rectangular slot transversely under a microstrip line is proposed. In the frequency characteristics of its unit cell, an attenuation zero is observed close to the attenuation pole. The DGS unit is represented by Cauer's T-network, modeled by a third order elliptical lowpass filter and finally equivalent L-C parameters are extracted. Several studies have been accomplished on the influence of the geometric modification of the filter on its characteristics. Better transition sharpness, lower passband insertion loss and broader stopband are observed, compared to popular dumbbell DGSs due to its additional attenuation zero. The two-cell configuration of this DGS produces a three-pole lowpass filter having wide and deep stopband at low cutoff frequency. This is applied under the input and output feed lines of a parallel-coupled bandpass filter for suppressing harmonic frequencies. A lowpass filter is realized using cascaded investigated DGS and dumbbell DGS under a microstrip line.     

Design of a wideband common-mode filter using approximate closed-loop pattern of compact C-shaped defected ground structure

A compact common-mode filter is proposed to suppress common-mode noise for application of high-speed differential signal traces. The filter adopts one big C-shaped defected ground structure (DGS) cell in the left of ground plane and two small C-shaped DGS cells with opposite direction in the right of ground plane. Because these DGS cells have different dimensions, the filter has three adjacent equivalent resonant points, which can suppress wideband common-mode noise effectively. The left C-shaped DGS and its adjacent C-shaped DGS cell form an approximate closed structure, which can efficiently reduce the influence of the mutual capacitance. The filter provides a common-mode suppression from 3.6 GHz to 14.4 GHz over 15 dB while it has a small size of 10 mm10 mm. The fractional bandwidth of the filter is 120%, and the differential signals still keep good signal integrity. The experimental results are in good agreement with the simulated results.     

DGS微带线滤波器设计

利用三维场分析法分析了DGS微带线的频率特性，利用电路分析法讨论了DGS微带线的等效LC电路及其参数提取。然后讨论了哑铃的形状、大小、间隙以及介质介电常数对其频率特性的影响。最后给出采用DGS微带线设计的低通滤波器的仿真结果和实验测试结果。     

Compact asymmetric coplanar waveguide filter

The design and implementation of a novel asymmetric coplanar waveguide (ACPW) band rejection filter using defected ground structure (DGS) is presented. The proposed ACPW DGS technology provides bandgap characteristics with only one cell in the lateral ground plane. The equivalent circuit model of the proposed DGS unit section is described. Measurements of ACPW DGS showed good agreement with simulation and the proposed model.     

一种新型SRR缺陷地面结构低通滤波器

该文提出一种新型开口谐振环(Split-Ring Resonator, SRR)缺陷地面结构(Defected Ground Structure, DGS)。这种结构与传统哑铃形DGS结构相比,具有陡峭的带隙和平坦的低通特性。文中详细分析了开口谐振环DGS单元的等效电路以及结构参数与电参数之间的关系。在此基础上提出一种加载开路枝节的SRR DGS单元模型以提高带外抑制,采用这种单元的级联周期结构设计并制作了一种紧凑的S波段低通滤波器。测试结果表明,该滤波器带内插损小于0.5dB,带外抑制度在30 dB以上。     

基于缺陷地面结构和补偿微带线的低通滤波器

提出了一种新型一维周期缺陷地面结构（DGS）单元。文中给出了3个不同尺寸单元的5参数变化曲线,并使用DGS单元进行级联,形成一种补偿微带线。设计了一个低通滤波器,计算和测试结果显示该结构单元的截止频率由结构单元的物理尺寸决定,单元级联形成的多级低通滤波器具有良好的带通、带阻和谐波抑制特性。