Compact superconducting single-and dual-band filter design using multimode stepped-impedance resonator

This study presents two multimode stepped-impedance structures to design single-and dual-band filters. Transmission zeroes are introduced for the single-band filter by using dual-mode stepped-impedance resonators. The single-band filter with high selectivity is centered at 6.02 GHz and has a fractional bandwidth （FBW） of 25.6%. Four stubs （two low frequency and two high frequency ones） are connected to the rectangular patch in the center to construct a quadruple-mode resonator. The independent conditions of the center frequencies of the high and low bands of the resonator are analyzed. A dual-band filter, which operates at 1.53 GHz and 2.44 GHz with FWBs of 12.1% and 14.1%, respectively is designed. The single-and dual-band filters are both fabricated with double-sided YBCO films and they can be used in mobile and satellite communications.

COMPACT BANDPASS FILTER WITH HIGH SELECTIVITY AND WIDE STOPBAND USING SLOTTED STEPPED-IMPEDANCE RESONATOR

In this paper,a Slotted Stepped-Impedance Resonator (SSIR) is proposed.Due to the slots in the low-impedance section of the conventional SIR,the new resonator has a lower fundamental resonance f0 and can provide a potential finite transmission zero fz close to f0.Based on the proposed SSIR,a fourth-order Chebychev BandPass Filter (BPF) is designed at f0=1 GHz.The measured results show that a better than-65 dB rejection is achieved on both the lower and the upper stopband.Moreover,the new filter has a wide-30 dB rejection upper stopband from 1.13f0 to 6.52f0.The fabricated filter exhibits a size of The new filter has a planar topology and is easily integrated with modern portable communication systems.

COMPACT INTERLOCKED-COUPLED FILTER USING FOLDED STEPPED-IMPEDANCE RESONATORS

A microstrip interlocked-coupled bandpass filter is proposed with a markedly compact structure. The low-impedance open-end line of the quarter-wavelength Stepped-Impedance Resonator (SIR) is replaced by two open-end high-impedance lines, which not only facilitate the coupling mechanism but also provide the strong electric coupling between resonators. With the proper utilization of folded SIRs, the occupied area of coupled-resonator pair can be reduced. By applying the proposed coupled-resonator pair, the passband filter with the compact size can be realized. Good agreement between measured and simulated results is observed. The proposed filter is desirable for compact and high-performance microwave circuit applications.

Analysis and Design of Planar Tunable Inner-Coupling Step Impedance Resonator

A full planar tunable band pass resonator is introduced, which is constructed by using novel symmetric step impedance resonator （SIR） and hyperabrupt varactors for wide bandwidth tuning and size reduction. The equivalent circuit model of the proposed resonator is set up. Theoretical analysis based on transmission line as well as odd and even-mode method is completed. The attractiveness of the approach presented lies in its simplicity. Based on the detailed analysis, a 6 GHz to 10 GHz varactor tuned resonator is designed, fabricated, and measured. It shows wideband tuning ability of 37%. The experimental results of the resonator have a good agreement with the analysis results.

Tri-band bandpass filter based on coupled stepped impedance resonators

A novel tri-band bandpass filter （BPF） is proposed by using cross-coupled stepped impedance resonators （SIRs）, which can operate at 2.4 GHz, 3.5 GHz and 5.25 GHz respectively. In engineering application, it is suitable for wireless local area network （WLAN） and worldwide interoperability for microwave access （WiMAX）. In addition, the passband of this filter can be easily controlled by changing the electrical parameters of the resonators. So it is helpful to the selection of passband in engineering applications. For in-depth analysis, the equivalent circuit of the filter is also proposed. At last, it shows that the measured results agree well with the simulated results. The insertion loss of the filter within each passband is less than 1.9 dB, meanwhile two transmission zeros are obtained which can be able to meet the engineering requirements.

Design of Miniature UWB-Based Antenna by Employing a Tri-Sectional SIR Feeder

A novel ultra-wideband(UWB)-based microstrip antenna is presented in this work by using a slotted patch resonator,a tri-sectional stepped impedance resonator(SIR)feeder,as well as a reduced ground plane.The whole structure was realized on an FR4 substrate.The impact of incorporating several cases of ground planes on the input reflection has been thoroughly investigated under the same tri-sectional SIR feeder and by employing a slotted patch radiator.Since the complete ground plane presents an inadequate frequency response,by reducing the ground plane,the induced UWB responses are apparent while the antenna exhibits higher impedance bandwidth.The impact of both the uniform impedance resonator(UIR)as well as the SIR feeder on the input reflection has also been examined by following the same adopted reduced ground technique and using a slotted patch radiator.As a result,the UIR feeder exhibits a dual-band frequency response,when a wide notched band is incorporated in the range from 4.5–6.5 GHz.The dual-band response of the bi-sectional SIR feeder is still apparent with a narrower notched band in the frequency range from 4–5 GHz.As far as the tri-sectional SIR feeder is concerned,the UWB response is discernible without recording the existence of a notched band.Additionally,the antenna displays a higher impedance bandwidth compared with the previously reported steps.Our proposed antenna configuration is designed with highly compact dimensions and an overall size of 14×27.2 mm2.Moreover,it operates under the impedance bandwidth of 2.86–10.31 GHz that can be leveraged for numerous applications where wireless systems are used.Our approach presents several advantages compared with the other reported UWB-based antennas in the literature,whereas the measured S11 pattern is in good agreement with the simulated one.

Compact multilayer dual-band bandpass filter design using stepped impedance resonators

Compact dual-band bandpass filter(BPF)for the 5 th generation mobile communication technology(5 G)radio frequency(RF)front-end applications was presented based on multilayer stepped impedance resonators(SIRs).The multilayer dual-band SIR BPF can achieve high selectivity and four transmission zeros(TZs)near the passband edges by the quarter-wavelength tri-section SIRs.The multilayer dual-band SIR BPF is fabricated on a 3-layer FR-4 substrate with a compact dimension of 5.5 mm×5.0 mm×1.2 mm.The measured two passbands of the multilayer dual-band SIR BPF are 3.3 GHz-3.5 GHz and 4.8 GHz-5.0 GHz with insertion loss(IL)less than 2 dB respectively.Both measured and simulated results suggest that it is a possible candidate for the application of 5 G RF front-end at sub-6 GHz frequency band.

基于阶梯阻抗谐振器的双频宽带滤波功分器

为了更好地满足无线通信系统对多功能、多频段射频前端器件的要求,提出了一种基于阶梯阻抗谐振器的双频宽带滤波功率分配器。首先,使用单个T形谐振器实现双频滤波单元,同时采用阶梯阻抗技术引入了单独可调的高次模用于展宽双频功分器的高频通带带宽;其次,利用枝节加载技术实现额外谐振模式的引入,展宽了双频滤波功分器低频通带带宽;为了实现小型化设计,对部分微带线进行弯折,使得整个电路结构更加紧凑。此外,利用T形谐振器自身的滤波特性和在微带馈线上加载的开路枝节,在带外产生四个可控的传输零点,提高了通带外选择性;通过在微带馈线上加载扇形枝节和在输出端口引入隔离电阻,有效改善了滤波功分器的带内阻抗匹配效果和隔离度。为了进一步验证,对所提出的滤波功分器进行了加工和测试。该滤波功分器的中心频率为2.83 GHz和4.87 GHz,相对带宽分别为10.6%和11.7%,通带隔离度均大于14.5 dB。测试和仿真结果基本一致。

基于阶跃阻抗谐振器的四阶频率可调滤波器设计

提出一种基于阶跃阻抗谐振器的紧凑型四阶四零点频率可调滤波器设计。滤波器使用变容二极管加载的阶跃阻抗谐振器(VL-SIR),有效拓宽了滤波器的调谐范围。在VL-SIR之间引入交叉耦合,从而在滤波器通带近端产生一对传输零点,显著提高了滤波器的选择性。同时,引入源和负载端的交叉耦合,在通带远端生成一对传输零点,以提高带外抑制。此外,采用基于VL-SIR的频变耦合结构来实现恒定绝对带宽。仿真结果与实测结果吻合良好。测量结果显示,可调滤波器频率调谐范围为0.78~1.15 GHz,3 dB绝对带宽约为55±3 MHz,滤波器的回波损耗大于10 dB,插入损耗约为2.8~3.3 dB。

基于SIR的低损耗双频宽带滤波器

提出一种采用折叠阶跃阻抗谐振器结构的双频微带带通滤波器。利用新型平行电耦合方式实现了滤波器的小型化,引入零度馈电结构产生传输零点以改善带外抑制性能。实验结果表明,该滤波器结构紧凑,损耗低,带外抑制性能好,且通带的中心频率分别为2.4 GHz和5.2 GHz,带内性能良好,最小插损分别为0.72 dB和0.69 dB。

铁路机车电台设备电磁发射测量专用带阻滤波器设计

铁路无线通信设备发射的信号往往较强,因而在电磁发射测量过程中,极易导致测量接收机出现乱真响应。基于450 MHz无线列调机车电台通信设备的工作特性,研制了一种新型可调阶跃阻抗谐振器腔体窄带带阻滤波器,用于避免电磁发射测量过程中所引起的测量接收机过载问题。通过软件仿真和实物测试,验证了所设计的带阻滤波器较传统腔体滤波器减少了阻带带宽,具有良好的通带特性,且结构简单,体积较小,可以很好地满足机车电台电磁发射测量的需求,有效提高电磁发射测量结果的准确性。

一种新型小型化宽阻带低通滤波器设计

对基于阶梯阻抗加载发卡型谐振器的多级椭圆函数微带滤波器进行了讨论。通过把两个谐振器用等效于电感的细微带线连接起来构成二级低通滤波器,其在阻带带宽和阻带衰减方面与单谐振器滤波器相比,取得了非常明显的改善。新设计滤波器的3dB截止频率位于2GHz,在2.5~25GHz具有小于10dB的衰减,而滤波器的面积仅等效于0.081λg×0.096λg（λg是在截止频率2GHz的导波波长）,证明了此种谐振器在多级滤波器设计中的有效性。此外,为更好地理解此种滤波器工作原理,文中对单谐振单元滤波器的LC等效电路进行了提取。与其它微带低通滤波器相比,此种滤波器在小型化、宽阻带方面具有明显优势,可广泛应用于多种微波系统。

SIR带状线带阻滤波器的设计

将具有阻带特性的微带马刺线结构引入到带状线中,设计了一款中心频率为2.32 GHz,相对带宽为9.5%,阻带衰减为50 dB的三阶马刺线式带阻滤波器。相比于传统的并联开路短截线型带阻滤波器,马刺线式带阻滤波器的横向尺寸大为减小,结构更加紧凑。采用SIR(stepped-impedance resonator)结构,按相同指标设计了一款三阶SIR马刺线式带阻滤波器。与马刺线式带阻滤波器相比,SIR马刺线式带阻滤波器结构更为紧凑,纵向尺寸缩小约17%,并具有更好的谐波抑制特性。

微带多耦合SIR带通滤波器的设计

基于微带SIR的特性,提出了一种紧凑的微带多耦合带通滤波器结构,介绍了通过控制微带SIR谐振器的阻抗比值来调整二阶通带中心频率的位置,从而实现二阶杂波抑制和改善滤波器上边阻带衰减特性的原理。最后设计了一个中心频率为3.65 GHz,分数带宽约为3.5%的微带多耦合SIR带通滤波器,仿真表明其频率响应在1阶杂波频点处有-10 dB左右的衰减,使得滤波器在上边阻带的衰减更陡峭,通带更对称。制作的电路在中心频率处的插入损耗测试结果为-3.2 dB,带宽大约为120 MHz,和仿真结果比较一致。

基于组合多通带谐振器的三频滤波器设计

为得到三个通带中心频率及带宽均可独立调节的三频滤波器,提出了一种基于组合多通带谐振器的三频滤波器设计方法.首先采用阶跃阻抗谐振器和半波长谐振器构建组合多通带谐振器;然后分别采用级联型和伪交指型的耦合结构设计了两种三频滤波器,每种结构都有足够的自由度来获得所需的带宽和中心频率;最后设计并加工了两个工作在2.45、3.50和5.25GHz的三频滤波器.测量结果与仿真结果吻合良好,验证了文中三频滤波器设计方法的有效性.

小型化SIR同轴腔体双通带滤波器研究

基于频率变换技术的双通带滤波器综合理论,应用阶跃阻抗谐振器(SIR)的基本原理,在双通带滤波器设计中引入λg/4型SIR同轴腔体谐振单元,设计了一种交叉耦合型拓扑结构的小型化同轴腔体双通带滤波器,相比于实际长度λg/4的传统滤波器,尺寸压缩了约50%。仿真结果显示,两个通带内回波损耗均大于20 dB,插入损耗小于0.1 dB,通带之间的阻带衰减特性良好。该滤波器的两个传输零点提高了阻带抑制度,满足了通信系统对滤波器小型化、低插损、高选择性的要求,能够广泛应用于双频带通信系统。

新型交叉耦合双模宽带带通滤波器设计

采用变形的阶梯阻抗谐振器(SIR)设计了一款小型化、高性能新型宽带带通滤波器。通过对经典的SIR进行弯折,在高阻抗线之间引入交叉耦合构成交叉耦合多模谐振器。该谐振器具有与经典SIR相同的谐振模式,由前两个谐振模式构成通带,并且在上下阻带产生两对对称的传输零点。该带通滤波器结构紧凑、带内差损非常小,同时由于带外传输零点的存在,一阶杂散得到有效抑制,带外特性明显改善。

双频阶梯阻抗谐振器滤波器设计

为满足无线通信需求,采用4级半波长谐振器设计了一种应用于无线局域网络(IEEE-802.11a/b/g)的双频带通滤波器。运用HFSS和Designer两种仿真软件分别对所设计滤波器的带内插入损耗和带外抑制特性通过调节阻抗比和谐振器的长度进行了仿真和优化。仿真结果的一致性表明该结构的稳定性良好,在2个中心频率为2.4 GHz和5.2 GHz的通带内,插入损耗分别小于1.6 dB和1.9 dB,相对带宽分别大于5.8%和6.7%;在频率为1.6 GHz、4 GHz和6.3 GHz处的抑制损耗达到45 dB,阻带抑制特性满足设计要求。

基于SIR结构的双频宽带耦合器

针对传统双频耦合器工作带宽窄的问题,提出了一种基于阶梯阻抗谐振器(SIR)的双频宽带分支耦合器设计方法.通过调节SIR的阻抗,可以在工作的双频段(高低频段)上灵活地调节耦合器谐振频率的位置和耦合器的带宽.最后设计并加工了一个工作在2.20和5.50GHz的双频宽带3 dB分支耦合器.该耦合器覆盖了全球移动通讯系统的1.80GHz频段和无线局域网系统的2.45、5.25、5.80 GHz频段.测量结果与仿真结果吻合良好,验证了文中双频宽带耦合器设计方法的有效性.

一种新颖的开口环地面缺陷结构低通滤波器

提出了一种新颖的具有陡峭边带和宽阻带的小型化低通滤波器。通过把开口谐振环地面缺陷结构(Split-Ring Resonator Defected Ground Structure,SRRDGS)与阶梯阻抗梳状谐振器结合,提高了滤波器的选择特性,同时获得了宽阻带。对所提出的结构作了加工并进行了实物测量,测试结果表明:滤波器选择特性大于160dB/GHz,在2.98GHz到8.2GHz范围内抑制度大于20dB,而占用面积仅为20×25mm2。