高端锐截止的短截线超宽带滤波器

对传统短截线超宽带滤波器作了改进：首先,各短路短截线的长度不限定为1/4波长,且互相之间有差异,这就使得原本集中于2f0的N个传输零点在一定阻带范围内分散并优化分布;其次,在每个1/4波长连接传输线的中点位置加载一定长度和特性阻抗的开路短截线,从而在高频阻带范围内产生了若干新的传输零点。通过软件优化,高频阻带出现了等波纹抑制特性。该方案使得短截线滤波器的通带高端锐截止,且高频阻带的带宽变宽。实测结果证明了该方法的有效性。     

基于折叠短截线耦合理论的新型宽带带阻滤波器设计

提出一种新型的基于折叠短截线耦合理论的宽带带阻滤波器(BSF)设计方法.根据所提出的方法,设计了一款阻带范围可控、传输零点可控、阻带抑制良好的紧凑型宽带带阻滤波器.该滤波器分为上下两部分,上部分为对称的主传输线加载折叠短截线单元,下部分是由公共短截线拓扑而成的矩形贴片.可以通过改变短截线单元的间隙耦合和矩形贴片的长度来...     

新型D-CRLH传输线宽带带阻滤波器设计

提出一种新颖的对偶复合左右手传输线(D-CRLH TL)结构单元,设计了一款小型化四阶宽带带阻滤波器。通过缝隙耦合形成左手电容和右手电感,位于结构下方的矩形贴片形成右手电容,与矩形贴片相连接的短截线形成左手电感。可以通过改变矩形贴片宽度和短截线的长度来调节带阻滤波器的中心频率和带宽。滤波器有效设计尺寸为11.5 mm×6.7 mm,等于0.23λ×0.13λ(λ为中心频率在自由空间的波长),尺寸较小。仿真测试结果表明该滤波器阻带中心频率为5.6 GHz,20 d B阻带带宽为50%,50 d B阻带带宽为30%。     

一种S波段小型宽带微带带通滤波器优化设计

基于并联短截线谐振器与联接线变换器构成的传统微带带通滤波结构,提出了一种工作在S波段的改进型宽带带通滤波器。以三阶结构为例,通过将两侧并联短截线进行弯折,形成耦合线结构;将中间并联短截线进行拆分,变为并联的短路线和开路线,实现了在通带性能基本不变的前提下,获得阻带可调控的传输零点,进而提高过渡带陡峭度。为了进一步抑制阻带,在滤波器两侧级联扇形微带低通滤波结构,改善阻带性能。利用ADS和HFSS仿真软件对滤波器结构进行仿真优化设计,并最终进行了实物加工和测试。实测结果表明,通带内2~4 GHz插入损耗小于0.7 dB,回波损耗大于17 dB,通带外4.6~6.5 GHz 阻带抑制达到20 dB 以上。     

V波段波导短截线带通滤波器设计

设计和分析了V波段E面波导短截线带通滤波器。利用E面波导短截线带阻滤波器的通带-阻带特性与矩形波导的高通特性相结合,将波导短截线带阻滤波器嵌入WR-15矩形波导中,设计具有高阻带抑制性能、过渡边带陡峭、宽阻带范围的V波段宽带带通滤波器。采用"场"、"路"相结合的方法设计的带通滤波器,仿真与测试结果吻合较好,验证了该设计方法的有效性。经测试实现了18%的1 dB带宽,在50.0～57.8 GHz通带内插入损耗≤1 dB,阻带频率58.9 GHz处抑制为43.6 dBc。     

一种新颖U形缺陷地结构宽阻带低通滤波器

提出了一种通过微带短截线来改变U形缺陷地结构(DGS)截止频率的方法.利用微带短截线和一个U形DGS单元设计了一个宽阻带低通滤波器,并提出通过改变微带短截线的长度来控制该低通滤波器的截止频率的方法.通过仿真比较分析了该低通滤波器与文献中利用一个哑铃形DGS单元和低阻抗微带线方法、级联多个U形DGS单元方法设计的低通滤波器的特性.最后,给出了模拟结果和测试结果,验证了所设计的低通滤波器的有效性.     

新型的方形贴片双模微带带通滤波器

提出了一种新型的方形贴片双模微带带通滤波器。该滤波器结构有一个切角,并且在贴片中心处开了一个两臂等长的十字槽,采用正交直接馈电方式,并在每条馈线上引入了一节与谐振腔有一定耦合的开路短截线。该结构在上下阻带都产生衰减极点,馈线上引入的微带线有效地抑制了寄生通带,提高了阻带抑制特性。仿真结果表明,该滤波器在中心频率2.9 GHz处,回波损耗优于–30.9 dB,通带内最小插入损耗为–0.1 dB,与实测结果基本一致。     

一种新颖的PBG宽阻带低通滤波器

 本文首次提出综合PBG结构和微带线结构两因素,来设计滤波器的概念.与普通PBG结构滤波器不同的是,本文采用具有T形和十字形短截线的微带线代替直线微带线,在接地板上只需刻蚀一列PBG结构即可构成宽阻带低通滤波器.文中以T形短截线PBG结构的低通滤波器为例,运用时域有限差分法(FDTD),分析了在不同短截线长度和PBG结构方孔边长的情况下,该滤波器的传输特性.文中还给出了该滤波器和Rumsey方法与Kim方法设计的级联、并联两种PBG结构低通滤波器的传输特性的模拟结果及其对比分析.最后,文中给出了模拟结果和测试结果,来验证所设计的低通滤波器的有效性.     

一种高滚降宽阻带低通微带滤波器

普通的阶梯阻抗低通滤波器滚降系数一般低于80 dB/GHz,阻带抑制小于20 dB,使其应用受到较大限制;文中首先从理论上分析并设计了具有宽阻带优势的阶梯阻抗滤波器,然后引入扇形短截线结构提高滚降系数,设计了一款通带为0~6 GHz 的高滚降宽阻带的微带低通滤波器。利用ADS 和HFSS分别对滤波器进行了建模、仿真和优化;最后采用RO4003 板材加工并对实物进行了测试。测试结果显示,所设计的滤波器3 dB 截止频率为6.02 GHz,滚降系数为123 dB/ GHz,阻带6.24~20 GHz,阻带抑制大于30 dB。     

基于非对称辐射单元的毫米波全金属漏波天线

周期漏波天线具备后向端射-前向端射的连续波束扫描能力。全金属周期漏波天线在毫米波雷达等 系统中具有明确的应用前景,但普通方案受制于开放阻带效应,边射性能差、扫描性能受限。目前抑制开放阻带效 应的方法主要包括加载四分之一波长变换器或匹配短截线、不对等双辐射元、短路过孔匹配等,适合于全金属周期 漏波天线的解决方案尚待发掘。文中提出了一种采用非对称辐射单元抑制开放阻带效应的方法,并结合等效电路 模型进行机理分析和方法验证。采用非对称辐射单元设计了毫米波全金属波纹平行板波导周期漏波天线。该天线 在26. 5~36 GHz 频带内具有-47. 5°~8. 5°的连续波束扫描能力,且辐射效率高于78%。仿真和实验结果表明,该非 对称辐射单元能够很好地抑制开放阻带效应,适用于宽角频扫全金属周期漏波天线设计。     

Open- and short-circuit terminated series stubs in finite-widthcoplanar waveguide on silicon

Open- and short-circuit terminated series stubs in finite-width coplanar waveguide (FCPW) fabricated on high-resistivity Si are experimentally characterized over the frequency range of 2-40 GHz. In coplanar waveguide (CPW), these stubs are typically placed in the center conductor, but in FCPW, the stubs may also be placed in the ground planes resulting in novel circuit elements with characteristics that make the stubs useful for matching circuits and filters. Equivalent circuit models for the stubs are presented, and it is shown that when the stub is in the ground plane the resonant frequency is equal, the inductance and resistance is halved, and the capacitance is double the values of the same stub in the center conductor. Furthermore, it is shown that by varying the stub position in the ground plane, higher Q stubs can be obtained     

Dual-frequency power divider with isolation stubs

A novel dual-frequency power divider with isolation stubs is presented. To reduce the parasitic effects between the two stubs that are connected by the isolation resistor in traditional Wilkinson power dividers, a structure consisting of isolation stubs is proposed. The corresponding design equations are obtained to calculate the design parameters of the desired dual-frequency power divider. Finally, this design concept is validated by experimental results on a 0.95/2.09 GHz dual-frequency power divider.     

Bandstop Filter in Nonradiative Dielectric Waveguide Using Rectangular Resonators

A bandstop filter realized by means of rectangular resonators coupled to the center dielectric strip of a nonradiative dielectric (NRD) waveguide is described.This filter has the advantage that it is simple to manufacture, making use of a center dielectric of standard cross section. The design procedure is similar to the conventional strip line design procedure, with the stubs replaced by "stubs" of dielectric, or resonators. The design equations for the stub coupling are derived the properties of the stubs are obtained through measurement.     

Evaluation of the Snyder dipole

A dipole made of coaxial stubs, with or without wire end extensions, where the stubs act as built-in matching elements, was patented by Snyder. This type of dipole is analyzed, with the result that the bandwidth is roughly equal to that of a dipole of the same fatness, with a lumped resonant circuit at the terminals. The bandwidth is also equal to that of a comparable folded dipole, but the impedance of the latter is four times larger.     

Ultra-Wideband (UWB) Bandpass Filter With Embedded Band Notch Structures

A compact ultra-wideband (UWB) bandpass filter (BPF) with narrow notched (rejection) band in the UWB passband realized on a microstrip line is implemented and presented in this letter for use in wireless communication applications within the unlicensed UWB range set by the Federal Communications Commission (FCC). The filter consists of five short-circuited stubs separated by nonredundant connecting lines in order to exhibit a high selectivity filtering characteristic. The narrow notched (rejection) band was introduced by using a new technique which involves embedding open stubs in the first and last connecting lines in order to reject any undesired existing radio signal which may interfere with the determined UWB passband. The bandwidth of the notched filter can be controlled by adjusting the width of the stubs or the gaps or both. The length of the stubs can be tuned to select a specific frequency for the notched band. The embedded stubs can be used to excite single or double band-reject response. Two UWB BPFs with narrow notched band having a fractional bandwidth (FBW) of about 4.6% and 6.5% were realized theoretically and verified by full-wave EM simulation and the experiment. Excellent agreement between the predicted and measured results was obtained and is demonstrated     

Planar Circuit Analysis of Microstrip Radial Stub (Short Paper)

Radial-line stubs have been found to work better than low-impedance rectangular stubs when an accurate localization of a zero-point impedance is needed. In this paper, microstrip radial-line stubs are analyzed using a planar circuit technique and characterized for design purposes. Experiments performed on various structures are in excellent agreement with the theory and confirm the suitability of such a structure as an altenative to a conventional straight stub.     

Knowledge-Based Artificial Neural Network Models for Microstrip Radial Stubs

Radial stubs are a superior choice over low characteristic impedance rectangular stubs in terms of providing an accurate localized zero-impedance reference point and maintaining a low input impedance value over a wide frequency range. In this paper, knowledge-based artificial neural networks are used to model the microstrip radial stubs. Using space-mapping technology and Huber optimization make the neural network models for radial stubs decrease the number of training data, improve generalization ability, and reduce the complexity of the neural network topology with respect to the classical neuromodeling approach. The neural networks are developed for design and optimization of radial stubs, which are robust both from the angle of time of computation and accuracy.     

Medium Frequency Reradiation from a Steel Tower Power Line with and without a Detuner

Measurements and computations of field strengths and tower base currents are presented for a power line section consisting of 5 towers strung with skywires and illuminated by a nearby monopole antenna. This is done first without detuning stubs, and then with detuning stubs on one tower to reduce the re-radiation. Good agreement is obtained between moment-method computations and full-scale measurements. Computational modelling techniques to represent the power line, the detuning stubs and ground effects are given and validated. The beneficial effect of increased stub spacing from the tower leg is identified.     

Experimental and theoretical characterization of miniature coplanar waveguide shunt stubs patterned on the centre conductor

Several new designs are presented for coplanar waveguide (CPW) open- and short-ended shunt stubs patterned on the centre conductor. Unlike conventional stubs which are patterned on the ground plane, the new designs are more compact and less radiative. They also provide more flexibility to the design of CPW circuits. The performance of the new stubs is verified by experiment and simulation and is found to be very satisfactory over the large frequency band 0–50GHz. Experimental results obtained for a conventional and new stub show that the new stub is less radiative.     

Uniplanar compact wideband bandstop filter

A uniplanar wideband bandstop filter is proposed using two bent open-end stubs. The proposed filter consists of the bent connecting line of /spl lambda//sub g//2 between two bent /spl lambda//sub g//4 stubs, which results in wideband design with a rejection bandwidth of 90% at 2.05 GHz. Further, the connecting line and stubs have the same characteristic impedance. The proposed filter compared to the conventional one is also more compact. The area of the novel filter is (/spl lambda//sub g//4)/sup 2/ at the center frequency of the stopband, while the area of the filter realized using the nonbent stubs and connecting line is 2(/spl lambda//sub g//4)/sup 2/ for the same stopband characteristics.