微带型曲折线慢波结构冷测特性的计算机仿真

在研究了微带型曲折线慢波结构色散特性、耦合阻抗等特性参数的分析方法基础上,利用电磁场仿真软件MAFIA和Microwave Studio对其进行模拟计算。对影响慢波电路特性的结构参数如微带宽度和微带厚度对其冷测特性的影响进行了仿真和分析,同时对介质杆支撑的曲折线慢波电路进行了分析。结果表明,微带宽度对其特性影响较为显著而微带厚度的改变影响不大,介质杆代替介质板使慢波电路的特性参数产生了较大的变化。     

微扰用介质薄片介电常数的精确测量

本文介绍作为平面结构慢波系统耦合阻抗测量用的介质薄片(云母片,陶瓷片等)介电常数ε_r的测量方法——谐振微扰法;并考虑到测试腔耦合元件电纳对测量结果的影响,提出了修正公式。在三厘米波段,对几种介质薄片进行了实际测量,并与传输线驻波比法进行了比较。这种测量方法还适用于各种半导体材料薄膜介电特性的测量。     

高阻表面交指形电容设计公式的改进

本文采用保角变换法和电容拼接技术对交指形电容进行精确的计算,对交指形高阻表面光子晶体设计公式进行了改进.该计算模型适用于宽范围的介电常数和介质层厚度,各指长度和缝隙宽度可以不同,并且很容易扩展到多层介质以及有覆盖层的情况.设计了三个光子晶体例子,对其表面波特性进行了模拟和测试,得出交指电容值,证明本文给出的计算公式更准确.     

一种壁厚渐变蜂窝宽带透波结构*

采用介电常数渐变结构是一种有效实现宽带透波的方法。为实现介电常数随厚度变化,本文提出了 一种壁厚渐变六边形蜂窝结构。根据蜂窝等效介电常数的近似计算公式和介质介电常数变化分布,计算出该渐变 结构的几何参数。基于渐变线宽带匹配理论,对空气和高介电常数介质进行宽带匹配设计,从而得到介质介电常数 随厚度渐变的分布规律。为验证该设计方法的有效性,采用CST 商用仿真软件,对该结构的周期单元透波性能进行 仿真。仿真结果表明该结构在垂直入射和大入射角情况下,具有良好的宽带透波特性。通过改变芯层材料厚度可 以进一步调整宽带透波特性的起始频率。     

基于新型CRLH-TL的双通带带通滤波器设计与仿真

提出了一种基于新型平面结构复合左右手传输线（CRLH—TL）带通滤波器设计方法。新型CRLH—TL结构由微带与共面波导双面结构在一定频率下通过耦合等效形成,左手电容部分通过介质基板上表面的金属板与接地面的互耦环缝谐振（CSRR,complementary split rings resonators）的中心导带耦合形成,使得加工简单;左手电感部分由CSRR部分形成,避免了过孔等带来的麻烦与损耗。基于此的带通滤波器结构紧凑,易于实现大宽带,性能优良,通带内插入损耗较好。     

一种新型微带曲折线慢波结构的设计

设计了一种新型微带曲折线慢波结构,该结构采用双介质杆支撑式的V型平面曲折线慢波电路。利用电磁场仿真软件HFSS对这种新型结构和传统微带曲折线慢波结构进行了分析比较,研究结果表明,新型微带曲折线慢波结构在不改变色散强弱的情况下,工作频段向高频端拓展且耦合阻抗有了很大提高,可以更好地工作在短毫米波段。并仿真分析了结构参数对高频特性的影响,所获得的仿真结果为器件的粒子模拟及计算慢波结构的工作效率奠定了基础。     

小型射频LC低通滤波器设计

研究射频LC低通滤波器的设计，通过仿真计算研究了以螺旋电感和平板电容作为基本元件的滤波器设计制作在不同介电常数的介质基板上时性能的变化情况，结果表明采用高介电常数的介质基板时滤波器的尺寸可以减小，同时性能指标也可以获得一定的改善。     

特异材料的平衡状态分析

传输线结构的Metamaterial的平衡点在研究其传输性质时具有重要的意义。文中对传输线结构的一维Metamaterial进行了电路仿真并从理论上讨论了Metamaterial平衡点的物理意义。当负介电常数的终止频率与负磁导率的终止频率一致时，禁带消失。从另一角度来看，当微带传输线的波阻抗与加载电容和加载电感所组成的负折射系统的波阻抗相同时，电路平衡。     

基于LCP基板的平面叉指电容研究

平面叉指电容作为电路系统中的重要器件,对电路性能影响极其重要。本文在50μm厚度双面覆铜的液晶聚合物(Liquid Crystal Polymer,LCP)基板上加工了多款平面叉指电容,系统研究了平面叉指电容的叉指长度、宽度和间距的变化对其电容值的影响规律。结果表明:叉指长度从3 mm增加到4 mm,叉指电容容值增加1.63 pF;叉指宽度从0.2 mm增加到0.3 mm,叉指电容容值增加2.35 pF;叉指间距从0.1 mm增加到0.2 mm,叉指电容容值减少0.75 pF。通过集总参数等效,建立了平面叉指电容的等效电路,分析了等效电路中集总器件和不同平面叉指电容物理结构参数的对应关系,为LCP工艺中电容的设计提供了技术参考。     

Ka波段低电压悬置双微带曲折线慢波结构的设计与测试

提出了一种悬置双微带曲折线慢波结构,介质基板悬置于封闭金属腔内,基板上下表面各镀有一条金属曲折线结构。该结构具有双电子束通道,电磁波具有对称的分布,因此,电磁波可以通过上下腔体与两束带状电子束互作用。通过仿真软件分析了其高频特性,设计工作电压和电流分别为2050 V和0.2 A,PIC仿真结果表明,在36 GHz处最大输出增益为26 dB,具有8 GHz的3-dB饱和功率带宽。实验测得该慢波结构反射损耗低于-10 dB,同时分析了慢波结构制备过程中影响传输损耗的主要因素。     

小型化微波悬置屏蔽微带线滤波器的设计

本文给出了悬置屏蔽微带线交指滤波器的设计公式，并成功的研制了Ｘ线段小型化悬置屏蔽微带线交指滤波器，实验结果和理论计算吻合得很好。     

人工传输线传输特性的分析与设计

人工传输线以其慢波效应可以使微波部件小型化,因而得到了广泛应用。首先介绍了人工传输线的基本原理,给出了一种简洁的等效电路模型,然后推导出了基于该模型的传输特性计算公式;在此基础上,根据仿真结果推算出各等效电路参数,从而得到了人工传输线传输特性与等效电路参数的关系;最后设计制作了人工传输线,测试结果与分析结果比较吻合,证明了提出的分析模型是有效的。为进一步简化设计平面型人工传输线奠定了基础。     

A compact and high performance dual-band bandpass filter based on unbalanced composite right/left-handed transmission lines for WLANs applications

In this paper, a novel compact microstrip dual-band (DB) bandpass filter with high selectivity for wireless local area networks applications is proposed. The design procedure is based on unbalanced composite right/left-handed (UCRLH) transmission lines (TLs). The DB features can be achieved by unbalancing the CRLH transmission line. The necessary conditions to obtain a discontinuous transition between the left- and right-handed bands, intended to provide UCRLLH TL, are investigated. The application of this technique to design of compact DB filters is illustrated. The structure of the proposed DB filter is implemented by a series interdigital capacitor located between two microstrip lines that shorted to the ground plane by vias. The vias with microstrip lines acting as a shunt connected inductor while the series capacitor is realized by interdigital capacitor. The design procedure based on a simple equivalent circuit is also introduced. The proposed filter has advantages such as compact size, easy fabrication, high selectivity, low insertion loss, high return loss and, design flexibility. To validate the proposed technique, the proposed DB filter has been fabricated and tested. Good agreement has been found between simulation and measurement results. The total size of the proposed UCRLH DB filter is 0.17 λ_g × 0.048 λ_g, where λ_g is the guided wavelength of the lower pass-band. The size of the proposed DB filter is more compact in comparison with known similar filters.     

Microstrip Interdigital Hairpin Resonator With an Optimal Physical Length

In this letter, we report a novel microstrip interdigital hairpin resonator by having the parallel coupled lines in a conventional miniaturized hairpin resonator replaced by an interdigital capacitor. Equations are derived in order to design the resonator with an optimal physical length. It will be proved that the novel resonator can achieve even more size reduction than the conventional miniaturized hairpin resonator owing to the employment of the slow-wave structure. Finally, a four-pole cross-coupled bandpass filter using the optimal resonator is fabricated as verification     

Transmission line approach of left-handed (LH) materials and microstrip implementation of an artificial LH transmission line

A transmission line (TL) approach of left-handed (LH) materials is proposed. The transmission characteristics of an ideal LH-TL are presented, the constitutive parameters of an equivalent LH material are derived and shown to be negative, and some LH-transmission paradoxes are explained. Next, a method to design an artificial LH-TL in the form of an ideal lumped-elements ladder network is described and illustrated with simulation results. It is shown that, in this line, left-handedness can be achieved without losses over an unlimited bandwidth, from the cutoff of the resulting high-pass filter to infinity, with excellent agreement with theory. Finally, a microstrip implementation of the LH line for microwaves, using interdigital capacitors and stub inductors, is demonstrated, with moderate insertion loss and a broad bandwidth of the order of 100%.     

基于P型交指结构的星载微带电路小型化设计

现有星载微波系统中大量使用了各种形式的微带电路,但由于微带电路在低频率时尺寸较大,不利于星载产品小型化,因此提出了一种基于交指结构的微带电路小型化设计方法。该方法采用两个交指电容和高特征阻抗微带线构造的仔型结构替代原有微带结构,从而减小微带电路尺寸。对该方法进行分析并给出了设计理论,进行了仿真及实测验证,并成功应用到多种不同形式的微带电路中。最后给出了两个已验证的实例,一个基于FR4材料的2.4 GHz 功分器和一个基于RO4003C的1.4 GHz 耦合器。该设计方法可以在不改变电性能的基础上减少微带电路约40%的面积。     

一种新型悬置微带滤波器的设计

本文给出一种新型的悬置微带滤波器结构，这种结构比常用的交指滤波器和发夹滤波器体积小。本文给出这种滤波器的设计公式。并设计了一个S波段窄带滤波器，试验结果和理论吻合很好。     

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.      

Embedded microstrip interconnection lines for gigahertz digitalcircuits

Transmission line structures are needed for the high-performance interconnection lines of GHz integrated circuits (ICs) and multichip modules (MCMs), to minimize undesired electromagnetic wave phenomena and, therefore, to maximize the transmission bandwidth of the interconnection lines. In addition, correct and simple models of the interconnection lines are required for the efficient design and analysis of the circuits containing the interconnection lines. In this paper, we present electrical comparisons of three transmission line structures: conventional metal-insulator-semiconductor (MIS) and the embedded microstrip structures-embedded microstrip (EM) and inverted embedded microstrip (IEM). In addition, we propose closed-form expressions for the embedded microstrip structures EM and IEM and validate the expressions by comparing with empirical results based on S-parameter measurements and subsequent microwave network analysis. Test devices were fabricated using a 1-poly and 3-metal 0.6 μm Si process. The test devices contained the conventional MIS and the two embedded microstrip structures of different sizes. The embedded microstrip structures were shown to carry GHz digital signals with less loss and less dispersion than the conventional MIS line structures. S-parameter measurements of the test devices showed that the embedded microstrip structures could support the quasi-TEM mode propagation at frequencies above 2 GHz. On the other hand, the conventional MIS structure showed slow-wave mode propagation up to 20 GHz. More than 3-dB/mm difference of signal attenuation was observed between the embedded microstrip structures and the conventional MIS structure at 20 GHz. Finally, analytical RLCG transmission line models were developed and shown to agree well with the empirical models deduced from S-parameter measurements     

基于多层结构的新型左右手混合传输线

通过利用微带到共面波导的多层耦合结构,设计并制作了一种新型的左右手混合（CRLH）传输线。在该结构中,串联电容可以方便的通过上下两层金属导体之间的耦合加以实现,克服了传统的共面交指电容的电容值有限并且调谐复杂的缺点。同时也研究了判断左手通带的方法,并将该方法应用到所设计的结构中,结果表明该传输线结构具有相对较宽的左手带宽并且在左手通带内匹配良好。