基于硅氧化层的嵌入式传输线制造

在有损耗的硅衬底上试制了传输线(微带以及共面波导),并嵌入在CMOS Cu/SiO2互连层中.对传输线的几何尺寸与其特征阻抗、损耗以及衰减因子进行了研究.结果表明嵌入在硅氧化层中的微带和共面波导可以在有损耗的硅片上低损耗地实现,为在硅片上设计微波和毫米波电路提供了必要的无源器件.     

低阻硅基厚膜聚酰亚胺上共面波导的损耗特性

制备了一种低阻硅基厚膜聚酰亚胺上的高性能共面波导传输线 ,并从理论上分析了传输线损耗的成因及其计算方法。聚酰亚胺膜厚 1 1 .5 μm的低阻硅 (0 .5 Ω·cm)上的共面波导传输线在 1 0 GHz下插入损耗为3 .5 d B/cm。然而 ,相同衬底上 ,无聚酰亚胺膜的共面波导传输线在 1 0 GHz下插入损耗为 5 0 d B/cm,损耗特性明显比前者差。测试结果表明聚酰亚胺层的介入能有效地改善传输线的损耗特性 ,且损耗随着聚酰亚胺膜厚的增加而降低。     

Low-Microwave Loss Coplanar Waveguides Fabricated on High-Resistivity Silicon Substrate

分别在普通的低阻硅衬底、带有3μm厚氧化硅介质层的低阻硅衬底和高阻硅衬底上设计并制备了微波传输共面波导.结果表明,低阻硅衬底导致过高的微波损耗从而不能使用,通过加氧化硅介质层,微波损耗可以大大减少,但是需要较厚的氧化硅厚度.直接制备在高阻硅衬底上的共面波导在所测试的26GHz的频率范围内获得低于2dB/cm的微波损耗,而且工艺十分简单.     

BST铁电薄膜高频特性的仿真分析研究

通过微波软件建模和理论分析方法来分析BST铁电薄膜材料在微波集成电路中的应用,旨在指导器件设计。借助microwave office和Ansoft HFSS&Q3D两个商业软件,构造微带传输线,共面波导传输线,微带低通滤波器和信号串扰等模型,并分析了加入钛酸锶钡(简称BST)薄膜前后各种模型的散射参数(S参数)和群延时。随后,在SiO_2和BST间加入过渡层(LNO,MgO),模拟分析微波元件参数的变化。同时还仿真分析了不同硅衬底厚度和不同BST薄膜厚度情况下的能量延时和S参数。结果表明,由于BST铁电薄膜的高介电常数特性,使得这层薄膜附近的信号线上会产生强烈的信号串扰。最后以共面波导传输线为示例,利用表面微细加工技术制备了共面波导传输线,并利用网络分析仪测试其传输性能,实际测试结果与仿真趋势一致。     

在高阻硅衬底上制备低微波损耗的共面波导

分别在普通的低阻硅衬底、带有3μm厚氧化硅介质层的低阻硅衬底和高阻硅衬底上设计并制备了微波传输共面波导.结果表明,低阻硅衬底导致过高的微波损耗从而不能使用,通过加氧化硅介质层,微波损耗可以大大减少,但是需要较厚的氧化硅厚度.直接制备在高阻硅衬底上的共面波导在所测试的26GHz的频率范围内获得低于2dB/cm的微波损耗,而且工艺十分简单.     

一种新型毫米波集成波导微带转换的分析与设计

提出一种新型集成于单层微带基片的毫米波集成波导微带转换 ,由一圆形微带谐振器、微带共面波导探针组成。利用全波分析软件对该转换器进行了分析计算、优化设计。测试了波导微带转换实物 ,结果表明 ,在Ka波段在 1 GHz频带内 ,该波导微带转换具有较低的插入损耗 ( <0 .4d B)和反射损耗 ( <-1 4d B)。可满足相关毫米波微带集成电路系统的应用要求。     

微机械传输线的毫米波应用

以几种典型的毫米波波段微机械传输线结构为研究对象，讨论了近几年的最新研究成果，包括微带、带状线、开放和封闭的共面波导。微机械传输线能够充分降低介质损耗，具有传输损耗小、工作频带宽、色散小、制作工艺能与传统集成电路工艺兼容等特点，是毫米波波段平面集成传输线应用的首选技术方案，同时微机械传输线的出现为毫米波单片集成电路以及毫米波系统的微型化提供了解决方案。     

非对称宽边耦合CPW微波滤波器的散射参数设计

非对称支持宽边耦合共面波导可看作是非均匀介质中的非对称耦合传输线 ,文中在非均匀介质中的非对称耦合传输线散射参数的基础上 ,推导出非对称宽边耦合共面波导的散射参数。利用所得散射参数研制了非对称支持宽边耦合共面波导滤波器 ,试验结果表明采用散射参数进行电路分析和设计的有效性。设计研制了f =3～ 5GH z的带阻滤波器 ,采用微波复合介质板 (εr=9.6、厚度为 0 .8m m) ,底层填充介质为聚四氟乙烯材料(εr=2 .1) ,上层为空气 ,上、下宽边耦合共面波导的中心导带宽度为 w =3mm ,槽宽为 sg=0 .50 mm ,长为 1=12 .57mm。上、下共面波导距离屏蔽盒顶、底的高度为 h1=10 mm。引出线采用微带渐变线进行阻抗匹配。这些为非对称支持宽边耦合共面波导在三维 (多层 )微波集成电路中的应用奠定了基础     

光激发LT—GaAs共面微带传输线THz色散与衰减特性

彩和半经验色散公式分析了ＬＴ－ＧａＡｓ衬底共面微带传输线的ＴＨｚ模式色散与切伦柯夫辐射损耗特性,同时计算了导体欧姆损耗和衬底介电损耗,结果表明,较小的横向尺寸有利于改善ＬＴ－ＧａＡｓ共面微带传输线模式色散和辐射损耗特性。较大的横向尺寸比可降低导体欧姆损耗。     

不同材料上共面波导线的损耗研究

研究不同衬底材料上共面波导(CPW)线的损耗特性。实验结果表明,采用低阻SOI(20Ω·cm)作衬底制作的共面波导线的损耗比在低阻硅(20Ω·cm)上制作的有明显减少;而采用低阻硅,并沉积1μmSiO2作衬底的CPW线损耗大大降低。采用高阻SOI(1000Ω·cm)制备的CPW线在2GHz损耗仅为0.13dB/mm;通过在低阻硅上采用地屏蔽技术也可以有效地改善传输线的损耗特性,在整个频段内的损耗可与高阻SOI硅衬底上相比拟。     

Through-silicon-chip transmission lines

Through-chip transmission lines connecting the frontside and backside of high-resistivity wafers are fabricated using bulk-micromachining and backside metal patterning. Experimental results illustrate the feasibility of low-loss through-chip microstrips and coplanar waveguides for innovative integration concepts of radio-frequency and microwave systems in silicon technology     

Electromagnetic coupling of coplanar waveguides and microstriplines to highly lossy dielectric media

The spectral-domain technique is utilized to analyze the coupling characteristics of coplanar waveguides and microstrip lines coupled with multilayer lossy dielectric media. Numerical results illustrating the dispersion characteristics of coplanar and microstrip lines, as well as the various electric field components coupled to highly lossy dielectric media, are presented. It is shown that the presence of a superstrate of lossless dielectric between the coplanar waveguide and the lossy medium plays a key role in setting up an axial electric field component that facilitates leaky-wave-type coupling to the lossy medium. The thickness of the superstrate relative to the gap width in the coplanar waveguide is important in controlling the magnitude of this axial electric field component. The coupling characteristics of the microstrip and coplanar lines are compared, and results generally show improved coupling if coplanar waveguides are utilized. Values of the attenuation constant α are higher for coplanar waveguide than for microstrip line, and for both structures α decreases with frequency     

Characterization and attenuation mechanism of CMOS-compatible micromachined edge-suspended coplanar waveguides on low-resistivity silicon substrate

This paper presents detailed characterization of a category of edge-suspended coplanar waveguides that were fabricated on low-resistivity silicon substrates using improved CMOS-compatible micromachining techniques. The edge-suspended structure is proposed to provide reduced substrate loss and strong mechanical support at the same time. It is revealed that, at radio or microwave frequencies, the electromagnetic waves are highly concentrated along the edges of the signal line. Removing the silicon underneath the edges of the signal line, along with the silicon between the signal and ground lines, can effectively reduce the substrate coupling and loss. The edge-suspended structure has been implemented by a combination of deep reactive ion etching and anisotropic wet etching. Compared to the conventional silicon-based coplanar waveguides, which show an insertion loss of 2.5dB/mm, the loss of edge-suspended coplanar waveguides with the same dimensions is reduced to as low as 0.5 dB/mm and a much reduced attenuation per wavelength (dB//spl lambda//sub g/) at 39 GHz. Most importantly, the edge-suspended coplanar waveguides feature strong mechanical support provided by the silicon remaining underneath the center of the signal line. The performance of the coplanar waveguides is evaluated by high-frequency measurement and full-wave electromagnetic (EM) simulation. In addition, the resistance, inductance, conductance, capacitance (RLGC) line parameters and the propagation constant of the coplanar waveguides (CPWs) were extracted and analyzed.     

The influence of finite conductor thickness and conductivity onfundamental and higher-order modes in miniature hybrid MIC's (MHMIC's)and MMIC's

The effect of finite metallization thickness and finite conductivity on the propagation characteristics of conductor-backed CPW on thin substrate is rigorously analyzed. A self-consistent approach is used together with the method of lines (MoL) to determine the propagation constant, losses and field distribution of the fundamental and first two higher-order modes in coplanar waveguides (CPWs) with finite metallization thickness and lossy backmetallization. The method used is general and can be applied to miniature MHMICs and MMICs including lossy semiconductor substrate. It is shown that the onset of higher-order modes limits the usable frequency range of conductor-backed CPWs. The analysis also includes microstrip transmission lines on thin substrate material. It is demonstrated that a resistive strip embedded into the microstrip ground plane may potentially be useful in the design of integrated planar attenuators     

Artificial Dielectric Shields forIntegrated Transmission Lines

We present a novel shielding method for on-chip transmission lines built on conductive silicon substrates. The shield consists of an artificial dielectric with a very high in-plane dielectric constant, built from two patterned metal layers isolated by a very thin dielectric film. Inserted below an integrated coplanar transmission line, the artificial dielectric layer blocks the electric field of the line from entering the silicon substrate. Shielded coplanar waveguides fabricated on a conventional silicon wafer show a two- to three-fold loss reduction compared to unshielded lines at frequencies below 30 GHz.     

Dispersion in Shielded Planar Transmission Lines on Two-Layer Composite Substrate

The singular integral equation technique has been used to analyze a shielded planar transmission line, which allows one to calculate the dispersion characteristics of shielded microstrips on two-layer substrates as well as the effect of shielding on coplanar waveguides. Dispersion curves for suspended substrate microstrips and the variation of the relative phase velocity, with frequency, of coplanar waveguide (CPW) on alumina substrates of finite thicknesses and variable ground plane positions are presented. The results of computations with the lowest order 4 x 4 determinant show good agreement with the available data.     

Efficient quasi-TEM frequency-dependent analysis of lossy multiconductor lines through a fast reduced-order FEM model

An efficient finite-element reduced-order quasi-TEM model for the frequency-dependent characteristics of lossy multiconductor transmission lines is presented. Conductor losses are evaluated as functions of frequency through a magneto-quasi-static model. Numerically generated problem-matched basis functions reduce the problem size and, therefore, the CPU time required by frequency sweeps without appreciable loss of accuracy. The proposed approach is applied to complex coplanar waveguides and to multiconductor interconnects; its results are compared with quasi-analytical techniques and with the full-wave finite-element method.     

硅衬底上共面线的特性及应用

基于理论和实验结果对深亚微米硅集成电路中的共面传输线的特性进行了研究,提出了硅衬底上传输线分布参数的提取方法和减小共面线衰减的一些设计准则.成功地将共面线应用在深亚微米高速集成电路的设计中,并给出了放大器芯片和共面线的测试结果.测试结果表明:在深亚微米CMOS高速集成电路中,用共面线实现电感是一种行之有效的方法.     

Miniaturized Wilkinson power dividers utilizing capacitive loading

The authors report the miniaturization of a planar Wilkinson power divider by capacitive loading of the quarter wave transmission lines employed in conventional Wilkinson power dividers. Reduction of the transmission line segments from λ/4 to between λ/5 and λ/12 are reported here. The input and output lines at the three ports and the lines comprising the divider itself are coplanar waveguide (CPW) and asymmetric coplanar stripline (ACPS), respectively. The 10 GHz power dividers are fabricated on high resistivity silicon (HRS) and alumina wafers. These miniaturized dividers are 74% smaller than conventional Wilkinson power dividers, and have a return loss better than +30 dB and an insertion loss less than 0.55 dB. Design equations and a discussion about the effect of parasitic reactance on the isolation are presented for the first time