Miniaturized coplanar waveguide stop band filters based on multiple tuned split ring resonators

A novel compact stop band filter consisting of a 50 /spl Omega/ coplanar waveguide (CPW) with split ring resonators (SRRs) etched in the back side of the substrate is presented. By aligning SRRs with the slots, a high inductive coupling between line and rings is achieved, with the result of a sharp and narrow rejection band in the vicinity of the resonant frequency of the rings. In order to widen the stop band of the filter, several ring pairs tuned at equally spaced frequencies within the desired gap are cascaded. The frequency response measured in the fabricated prototype device exhibits pronounced slopes at either side of the stop band and near 0 dBs insertion loss outside that band. Since SRR dimensions are much smaller than signal wavelength, the proposed filters are extremely compact and can be used to reject frequency parasitics in CPW structures by simply patterning properly tuned SRRs in the back side metal. Additional advantages are easy fabrication and compatibility with MMIC or PCB technology.     

Resonant-type balanced composite right/ left-handed coplanar waveguide structure

A resonant-type balanced composite right/left-handed (CRLH) coplanar waveguide (CPW) structure based on split ring resonators (SRRs) is presented. An equivalent circuit model is used to describe its complicated behaviour. As the higher cutoff frequency of the left- handed (LH) band and the lower cutoff frequency of the right- handed (RH) band are identical, a continuous transition from LH band to RH band without a bandgap can be achieved. In addition, because of the presence of SRRs, the resonant-type balanced CRLH CPW structure exhibits a very sharp cutoff in the lower edge of the transmission band.     

Spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators

In this letter, spurious passband suppression in microstrip coupled line band pass filters by means of split ring resonators (SRRs) is demonstrated for the first time. By etching SRRs in the upper substrate side, in close proximity to conductor strip, strong magnetic coupling between line and rings arises at the resonant frequency of SRRs. This inhibits signal propagation in the vicinity of that frequency, allowing the rejection of undesired passbands by properly tuning SRRs. To test this novel technique, we have designed and fabricated two different SSRs-based filters. In one case, the rings have been designed to suppress only the first spurious band, and SRRs have been etched at both sides of the 50-/spl Omega/ access lines. For the other prototype, SRRs have been etched on the active device region (i.e., surrounding the parallel coupled lines) and have been tuned to eliminate the first and second undesired bands. The measured frequency responses for these devices confirm the efficiency of this technique to suppress frequency parasitics, with rejection levels near 40 dBs, leaving the passband unaltered. Since SRRs are small particles (with sub-wavelength dimensions at the resonant frequency), this approach does not add extra area to the final layouts. Moreover, the conventional design methodology of the filters holds.     

基于液态金属的柔性频率可重构CPW天线设计

针对固态金属天线在受力弯曲后易产生裂纹导致功能失效的问题,本文提出一种频率可重构的柔性液态金属共面波导馈电天线.该天线由四个不同半径的开口谐振环（Split-Ring Resonators,SRR）构成,利用紫外光刻技术（ultraviolet lithography）制备天线的SU-8负模结构,其次浇注聚二甲基硅氧烷进行倒模并键合,最后将液态金属合金注入至微流沟道,完成天线的制作.通过机械施压方式改变不同谐振环间的通断状态,可在1GHz~6GHz范围内实现频率可重构,满足WLAN、WiMAX和部分C波段的通信要求.弹性体和液态金属的特性使天线具有更好的灵活性和耐久度,可应用于集成电子设备的弯曲表面.     

Compact left-handed microstrip line based on multiple layered step impedance resonators

A novel compact left-handed (LH) microstrip transmission line is presented. To establish a negative permeability and permittivity, the transmission line is loaded with step impedance resonators (SIRs) and an array of thin wires on dual-layer architecture. Compared to existing LH structures, which incorporate conventional split ring resonators (SRRs), the proposed structure is three times smaller in size whilst achieving the same performance. To illustrate the electromagnetic properties of the metamaterial, both analytical and full wave analysis were performed and utilized to determine the effective electromagnetic parameters of the proposed structures. The experimental results show that a microstrip line periodically loaded with SIR only produces a rejection of ?6?dB at a resonant frequency of 5.50?GHz. The results also indicate a pass-band response for a left-handed microstrip line (LHML) constructed from SIR and thin wire arrays at the same resonant frequency.     

低谐振频率电磁超材料单元设计与仿真

针对目前人工电磁超材料的谐振频率(吉赫兹(GHz)或太赫兹(THz))较大的问题,该文提出了一种新型尺寸较大的双面螺旋结构单元模型。通过HFSS仿真软件,建立了电磁超材料单元模型,分析了结构单元的S参数。采用Smith提取算法,得出了等效介电常数和等效磁导率的数学表达式。仿真结果表明,在2.0～2.1 MHz时,等效介电常数恒正,等效磁导率实部达到负极值,而等效磁导率的虚部也达到了最大值,即该频段为材料板的谐振频段,呈磁单负材料属性。     

具有宽带特性的超材料设计与分析*

分别提出具有宽带负磁导率特性的圆盘结构超材料和具有宽带双负特性的互联圆盘结构左手材料。对任意极化的垂直入射波,圆盘结构超材料可在8.71GHz到15.19GHz的频段上产生负的磁导率,而互联圆盘结构左手材料则可在6.04GHz到7.40GHz的频段上产生双负特性。通过有限元仿真、本构参数提取、表面电流分布计算、结构参数扫描等方法,对圆盘结构进行了详细分析。结果表明,该结构通过外加磁场激励起的电流环路构成磁谐振回路,进而获得负磁导率特性。利用无限划分的方法,分析了该结构实现宽带特性的原理,推导了等效的磁谐振频率和品质因数的计算公式,并给出其等效电路结构。通过参数扫描,分析了贴片半径、基板介电常数、损耗特性和入射角大小对负磁导率特性的影响规律。对互联圆盘结构左手材料,在提取其等效本构参数的基础上,着重分析了电响应特性,详细推导了等效电等离子体频率的计算公式。     

双频带电磁超材料单元设计及仿真

该文基于谐振型左手理论,提出一种将2种不同的多开口谐振环左手结构单元分别印刷在介质板的正、反面,这种复合结构实现了双频带左手特性。在微波频率范围内采用等效参数（NRW）提取算法,验证了该多开口谐振环的复合结构能实现负的介电常数和磁导率,同时采用LC谐振电路进行分析并解释其产生的机理。数值和仿真结果表明,存在2个介电常数、磁导率和折射率的实部都为负的频带。其负频带频率范围分别为16.5~18.96 GHz和22.8~24 GHz,负双频带带宽为3.66 GHz。由于其带宽性能良好的双负特性,可用于多频带或宽带微波器件的设计。     

Ultra-wideband bandpass filter with hybrid microstrip/CPW structure

A novel ultra-wideband (UWB) bandpass filter (BPF) is presented using the hybrid microstrip and coplanar waveguide (CPW) structure. A CPW nonuniform resonator or multiple-mode resonator (MMR) is constructed to produce its first three resonant modes occurring around the lower end, center, and higher end of the UWB band. Then, a microstrip/CPW surface-to-surface coupled line is formed and modeled to allocate the enhanced coupling peak around the center of this UWB band, i.e., 6.85GHz. As such, a five-pole UWB BPF is built up and realized with the passband covering the entire UWB band (3.1-10.6GHz). A predicted frequency response is finally verified by the experiment. In addition, the designed UWB filter, with a single resonator, only occupies one full-wavelength in length or 16.9mm.     

Microstrip Filter Designing by SRR Metamaterial

In this paper planar and compact band stop filter using split ring resonator (SRR) metamaterial is proposed. Band stop type attenuation is presented from L-to X-band. Low insertion loss in the pass band and high attenuation in the stop band can be considered as the advantage of this filter. Filter characteristics of SRR is presented using microstrip line. Here SRR is introduced in the substrate layer of microstrip line. It has been observed that the rejection level of the filter in stop band goes on increasing as we increase the number of SRR in the structure. Size of SRR is much less than the operating wavelength thereby several SRR can be introduced in substrate layer to provide a compact structure with high rejection level in the stop band. The frequency of filtering depends on the dimensions of SRR. The effect of varying the dimensions of SRR on the filtering frequency is also presented in this paper. It has also been observed by Nicolson-Ross-Weir approach that at the filtering frequency, value of relative permeability as well as relative permittivity for this structure is negative. This confirms that this structure behaves as a Left Handed medium.     

谐振频率可调的开口谐振单环结构

开口谐振单环(Split Single Ring Resonatots,简记SSRRs)和开口谐振环(SRRs)一样可以激励磁谐振,从而实现负的磁导率.提出在SSRRs结构中引入平行于其开口边的金属线的方法设计了新的磁谐振单元,研究了金属线的引入对谐振频率以及负磁导率特性的影响.数值模拟结果表明:随着金属线长度l的增加,SSRRs的谐振频率随之减小;随着金属线与开口边的间距d的增加,SSRRs的谐振频率随之增加.金属线的加入不会对SSRRs的负磁导率特性产生重要影响,改变金属线的结构参数可以实现μ＜0频段的调控.所提出的新的磁谐振单元对于新型负磁导率材料和新型左手材料的设计具有重要的实际意义,也为新型无线通信材料的实现提供了可能.     

Low-loss CPW on low-resistivity Si substrates with a micromachinedpolyimide interface layer for RFIC interconnects

The measured and calculated propagation constant of coplanar waveguide (CPW) on low-resistivity silicon (1 Ω·cm) with a micromachined polyimide interface layer is presented in this paper. With this new structure, the attenuation (decibels per centimeter) of narrow CPW lines on low-resistivity silicon is comparable to the attenuation of narrow CPW lines on high-resistivity silicon. To achieve these results, a 20-μm-thick polyimide interface layer is used between the CPW and the Si substrate with the polyimide etched from the CPW slots. Only a single thin-film metal layer is used in this paper, but the technology supports multiple thick metal layers that will further lower the attenuation. These new micromachined CPW lines have a measured effective permittivity of 1.3. Design rules are presented from measured characteristics and finite-element method analysis to estimate the required polyimide thickness for a given CPW geometry     

基于SRR的二阶方环滤波器小型化设计

移动通信的飞速发展为微波元件的小型化提出了更高的要求,左手材料因为其负介电常数和负磁导率的特性而被广泛用于天线和滤波器的小型化设计中,SRR作为左手材料的基本构成,用于设计三种基于其原理的二阶微带带通滤波器。文中滤波器具有依次降低的中心频率,代表滤波器尺寸的缩减。其中具有串联叠层式谐振结构的滤波器尺寸为单层结构滤波器尺寸的11%,表现出较好的小型化效果。仿真与实测结果吻合较好,验证了文中结构的可行性。     

Design, fabrication, and testing of double negative metamaterials

The design, fabrication, and testing of several metamaterials that exhibit double negative (DNG) medium properties at X band frequencies are reported. DNG media are materials in which the permittivity and permeability are both negative. Simulation and experimental results are given that demonstrate the realization of DNG metamaterials matched to free-space. The extraction of the effective permittivity and permeability for these metamaterials from reflection and transmission data at normal incidence is treated. It is shown that the metamaterials studied exhibit DNG properties in the frequency range of interest.     

Design and Analysis of Triple-Band Rectangular Microstrip Antenna Loaded with Notches and Slots for Wireless Applications

In this paper, a rectangular triple-band microstrip antenna has been designed for Bluetooth application by successively loading notches and slots of different dimension in radiating patch. The conventional microstrip antenna suffers with narrow impedance bandwidth. The current work affords an alternate option to enhance the bandwidth of antenna that resonates in triple-band operation. Initially, the antenna is resonating in single-band but after loading slots, the bandwidth of microstrip antenna has been obtained 1.97% (lower band), 10.35% (middle band) and 33.16% (upper band) resonating in triple-band with three resonant frequency at 1.422 GHz (lower resonant frequency), 1.791 GHz (middle resonant frequency) and 2.467 GHz (higher resonant frequency). The suggested antenna has upper frequency band in the range of 2.045–2.858 GHz resonating at 2.467 GHz frequency and it is appropriate for Bluetooth applications (2.40–2.48 GHz) and both lower band useful for other wireless (L-band) applications. The return loss of upper band is ??34.52 dB at 2.467 GHz. The suggested microstrip antenna is directly fed by 50 ohm microstrip line feed. The suggested antenna has been designed, simulated and analyzed by IE3D simulation software.

     

A compact planar ultra-wideband bandpass filter with multiple resonant and defected ground structure

A compact bandpass filter with dumbbell shape Defected Ground Structure (DGS) operating on ultra wide pass band (UWB – 3.1 to 10.6 GHz) is proposed. It is based on hybrid microstrip coplanar waveguide (dual sided metal) structure. A Multiple Resonant Structure (MRS) is constructed using coplanar waveguide (CPW) planar transmission line. The MRS makes the resonance using quarter wavelength and half wavelength open-ended CPW. The equispaced three resonances at lower (3.1 GHz), center (6.85 GHz) and higher edge (10.6 GHz) of the whole Ultra Wide Band is achieved using CPW MRS. To make the band as flat as possible, two more resonances are introduced using quarter wavelength microstrip patches on top of the commonly shared substrate, so the proposed filter becomes a five pole bandpass filter. A dumbbell shaped defected ground structure on either side of CPW MRS improves the return loss almost less than 20 dB over the whole UWB passband. The simulated results of proposed filter show good transmission response within passband and good rejection in out of the band. The simulated and measured results are very close to each other which proves the efficacy of proposed design.     

X波段SICL小型化带通滤波器的设计

为有效减小X波段滤波器的尺寸,减小通带损耗,对基片集成同轴线(SICL)结构进行了研究,提出一种阶跃阻抗(SIR)型SICL带通滤波器,并针对SICL谐振腔与其他平面电路的连接设计了一种由共面波导(CPW)向SICL谐振腔提供激励的平面结构,以便滤波器的测量。仿真结果表明,滤波器通带特性优异,其中心频率为10 GHz,带宽为1.5 GHz,尺寸为13 mm×7 mm,插入损耗为-0.8 dB。     

基于开口谐振环的毫米波差分移相器设计

该文提出了一种工作于30～32 GHz的毫米波差分移相器,其尺寸为30 mm×18 mm×0.127 mm。该移相器以微带线为基础进行设计,由中心圆环及一对开口谐振环(SRR)共同组成。通过改变中心圆环的半径大小实现在工作频段内的S参数优化。以参考线的输出相位为基准,通过改变开口谐振环半径依次实现22.5°、45°、90°的差分移相。结果表明,在所设计的频段内,该移相器的回波损耗小于-10 dB,插入损耗小于1.4 dB,仿真最大移相误差小于5°。该移相器结构简单,便于制造。通过实物样品测试,验证了其仿真结果的可靠性。     

Effective negative-/spl epsiv/ stopband microstrip lines based on complementary split ring resonators

In this letter a super-compact stopband microstrip structure is proposed. The frequency gap is produced by an array of complementary split ring resonators (CSRRs)-a concept proposed here for the first time-etched on the ground plane. This behavior is interpreted as due to the presence of a negative effective dielectric permittivity in the vicinity of resonance. The resulting device produces a deep rejection frequency band with sharp cutoff, and a pass band that exhibits very low losses and good matching. Due to the sub-lambda operation of CSRRs, the electrical size of the device is very small.     

Preparation of Iron Networks Hosted in Porous Alumina with Tunable Negative Permittivity and Permeability

Random composites of iron particles hosted in porous alumina were prepared from a facile impregnation‐reduction process. Interestingly, when the iron content exceeds the percolation threshold, the interconnection of iron particles results in the formation of iron networks. The composites then change from capacitive to inductive and the conductive mechanism changes from hopping conduction to metal‐like conduction. The negative permittivity was attributed to the plasma oscillation of delocalized electrons in iron networks, while the negative permeability could be ascribed to the strong diamagnetic response of current loops in iron networks. The negative permittivity behavior of the iron/alumina composite was analyzed using Drude model. Additionally, the fitting results indicated that the effective plasma frequency of the iron/alumina composite is much lower than bulk iron. Further investigations show that, the iron content and reduction temperature can easily tune the amplitude and frequency ranges of the negative permittivity and permeability. Moreover, the negative permittivity region and the negative permeability region can be pushed to the same frequency region by adjusting the iron content and reduction temperature. The impregnation‐reduction process opens a new way for the realization of tunable negative permittivity and permeability in random composites, and has great potential for the preparation of new types of double negative materials.