40-GHz coplanar waveguide bandpass filters on silicon substrate

We report a very simple process to fabricate high performance filter on Si at 40 GHz using proton implantation. The filter has only -3.4-dB loss at peak transmission of 40 GHz with a broad 9-GHz bandwidth. In sharp contrast, the filter on 1.5-/spl mu/m SiO/sub 2/ isolated Si has much worse transmission and reflection loss. This is the first demonstration of high performance filter at the millimeter-wave regime on Si with process compatible with current VLSI technology.     

Characterisation and modelling of mitered coplanar waveguide bends on silicon substrate

Mitered coplanar waveguide (CPW) bends are cascaded to form meandered CPW lines. Test samples are fabricated and characterised. In this article a compact, CAD-oriented semi-empirical equivalent circuit model is presented. The validity of the model is verified by comparing it with the experimental and simulation results. It is demonstrated that a meandered CPW with mitered bends has higher characteristic impedance and lesser loss when compared to straight CPWs.     

Novel coplanar waveguide to slotline transition on high resistivity silicon

Two novel coplanar waveguide (CPW) to slotline transitions have been fabricated and tested on high resistivity silicon. The first transition uses an air bridge to couple RF power from the CPW line to the slotline and has the entire circuit on the top side of the wafer. In the second transition, the grounded CPW (GCPW) line and the slotline are on opposite sides of the wafer and are coupled electromagnetically. The measured average insertion loss and return loss per transition are better than 1.5 and 10 dB, respectively, with a bandwidth greater than 30% at C-band frequencies.<>     

A low-loss V-groove coplanar waveguide on an SOI substrate

eguide causes about 50% less loss than the conventional one at a high frequency of up to 40 GHz.     

基于SOI衬底的低损耗V型槽共平面波导

由于SOI技术具有低损耗、低串扰等优异的电磁特性,在射频集成电路领域受到了越来越多的重视。基于SOI衬底的性能良好的无源器件对整个射频电路性能具有重要的作用。本文设计了一种基于SOI衬底的低损耗V型槽共平面波导,采用与CMOS标准工艺与硅的各向异性刻蚀技术相结合,去除了信号线与地线间距下方的SOI表层硅,实现了该传输线样品。测试结果表明,在测量的0-40GHz频率范围内,V型槽共平面波导的传输特性相比传统共平面波导有了极大改善,传输损耗减小了约50%。     

Low-loss coplanar waveguides interconnects on low-resistivity silicon substrate

This paper describes fabrication, characterization and simulation of low-loss coplanar waveguide (CPW) interconnects on low-resistivity silicon substrate. The fabrication of CPWs is low-temperature (below 250/spl deg/C) and incorporates a spin-on low-k dielectric benzocyclobutene (BCB) and self-aligned electroplating of copper. The performance of CPWs is evaluated by high-frequency characterization and EM simulation. CPWs with different line width (W) and line spacing (S) are investigated and compared. Using a BCB layer as thick as 20 /spl mu/m, CPW fabricated on a low-resistivity silicon substrate exhibits an insertion loss of 3 dB/cm at 30 GHz.     

Simple modeling of coplanar waveguide on thick dielectric overlossy substrate

We present a simple semi-empirical high-frequency equivalent circuit model to characterize the coplanar waveguide structure, which consists of a relatively thick metal line on very thick polyimide over a lossy substrate such as a Si BiCMOS wafer. Considering the geometric dependence of the conductive loss and the skin effect of the substrate loss, we derive modified models for the equivalent circuit elements. We verify the validity of our model by comparing it with experimental measurements. Our model is simple enough not only to be suitable for efficient circuit simulation but also to be useful for process characterization and design     

Analysis of slow-wave phenomena in coplanar waveguide on a semiconductor substrate

Slow-wave characteristics of a coplanar waveguide with substrate resistivity are analysed using the mode-matching technique. This waveguide is suitable for microwave monolithic integrated circuits because of its coplanar configuration. Numerical results are presented and compared with an experimental measurement in the literature.     

Neodymium-doped silica optical waveguide laser on silicon substrate

A waveguide laser with a Nd-doped silica core fabricated on a Si substrate using flame hydrolysis deposition and reactive ion etching techniques is described The Nd ion concentration was about 2000 p.p.m. and the optical loss at 1.05 μm was 0.85 dB/cm. CW lasing at a wavelength of 1.0515 μm with a threshold of about 150 mW was achieved successfully with pumping at 0.80 μm     

Fast optical wavelength interrogator employing arrayed waveguide grating for distributed fiber Bragg grating sensors

A new type of interrogator for distributed fiber Bragg grating (FBG) sensors that employs an arrayed waveguide grating (AWG) is proposed and its operating features are in detail investigated both theoretically and experimentally. The remedy for achieving the linear characteristics of wavelength detection as well as for insuring the reliable and environmentally stable operation of interrogation is proposed and its usefulness is demonstrated in good agreement with the experimental results. The developed interrogator consists of a fully passive, small, all-solid, rugged optical IC and can detect wavelengths of a great number of FBG sensors with high precision better than 0.5 pm and high speed.     

High-isolation bonding pad design for silicon RFIC up to 20 GHz

A simple depletion-insulation (DI) bonding pad structure is presented for silicon radio frequency integrated circuits (RFIC). Experimental results show that DI bonding pads can achieve a 3 to 7 dB improvement in cross-talk isolation compared with an ordinary bonding pad at all measured frequencies. An improvement of up to 90% in the Q-factor is also achieved by the DI pad indicating a significantly reduced high-frequency substrate loss. When compared with a ground-shield (GS) bonding pad, the isolation and the Q-factor of the DI bonding pad is inferior. However, the DI pad has a 40% smaller pad capacitance compared with the GS pad. The DI structure can be used in interconnect optimization to achieve high cross-talk isolation and low substrate loss, with minimal increase in parasitic capacitance.     

Silica-based optical waveguide on terraced silicon substrate as hybrid integration platform

A silica-based optical waveguide on a silicon substrate with terrace regions is proposed. Because the substrate is equipped with a low-loss waveguide and an optical bench at the same time, it is applicable to a hybrid integration platform.<>     

A broad-band lumped element analytic model incorporating skin effect and substrate loss for inductors and inductor like components for silicon technology performance assessment and RFIC design

We present a broad-band lumped element planar inductor model that is suitable for RFIC design in silicon technologies. We provide extensions of the modeling methodology to similar components such as differential inductors, baluns, and solenoid inductors. The analytic computation of the physics-based model components, incorporating both metal skin effect and substrate loss, is described. The model is validated using measured data from over 200 inductors made with five different silicon back-end process technologies. The physics-based implementation of the model allows its use for determining the optimum process technology characteristics for specific radio frequency integrated circuit (RFIC) designs. The analytical based implementation with lumped elements enables effective integration into a robust CAD system for efficient design of RFIC circuits.     

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.     

Printed dipoles electromagnetically coupled to coplanar waveguide for linear or circular polarisation

Two configurations are proposed for feeding printed dipoles with coplanar waveguide transmission lines. The coplanar waveguide feed is printed on a ground plane sandwiched between a high-permittivity substrate and a low-permittivity substrate which supports the antenna. Both linear and circular polarisation can be achieved. Measured results are presented.     

Interfacial adhesion of spin-coated thin adhesive film on silicon substrate for the fabrication of polymer optical waveguide

An investigation was carried out to study the interfacial adhesion of spin-coated polymeric adhesive thin film on a silicon substrate for fabrication of a polymeric optical waveguide. An adhesive shear button was made on a silicon substrate by using a photolithography process, and interfacial adhesion was measured with a Dage D2400 shear tester. Different adhesion strengths were found at different portions of the same sample. Higher adhesion strength was observed at the center of the substrate than at other locations of spin-coated adhesive films. Adhesion strength was also measured after heat exposure of the deposited and cured adhesive layer to evaluate the heat resistance of the adhesive film. After heat exposure, adhesion strength decreased substantially from all locations of the substrate due to the thermal degradation. Again, the adhesion was measured for different plasma-treated substrate conditions. The surface morphology of plasma-treated and untreated silicon substrates before deposition were characterized by atomic force microscopy. Lower adhesion strength was unexpectedly observed for all plasma-treated substrates, even for higher surface roughness. The fracture surfaces after shear testing were also characterized by optical microscopy. The complete study provides important indications for the fabrication of better-performing polymeric optical waveguides for photonic devices.     

Si基短波碲镉汞材料分子束外延生长研究

报道了在中波工艺基础上,Si 基碲镉汞分子束外延短波工艺的最新研究进展,通过温度标定、使用反射式高能电子衍射、高温计的在线测量和现有的中波 Si 基碲镉汞温度控制曲线建立及优化了 Si 基碲镉汞短波材料的生长温度控制曲线;获得的 Si 基短波 HgCdTe 材料表面光亮、均匀,表面缺陷密度小于3000 cm －2;基于此技术成功制备出了 Si 基短／中波双色材料。     

Power performance and scalability study of AlGaAs/GaAs double-recessed pseudomorphic high electron mobility transistors on unthinned substrate for coplanar waveguide circuit applications

We have investigated the power performance and scalability of AlGaAs/GaAs Double-Recessed Pseudomorphic High Electron Mobility Transistors (DR-PHEMTs) at 10 GHz on an unthinned GaAs substrate for CoPlanar Waveguide (CPW) circuit applications. It was found that the output power varied linearly with the logarithm of the device’s gate width ranging from 200 to 1000 μm. It increased at a rate of 0.01 dB/μm. That worked out to a doubling of output power (or 3 dB) for every 300 μm increase in the gate width. Gain decreased at a rate of about 0.005 dB/μm while PAE generally improved when the gate width was increased. As for DC measurement, the maximum transconductance of the device was about 375 mS/mm at V_G = −0.5 V and V_DS = 3 V. The gate-drain breakdown voltage (BV_GD) measured was −20 V, defined at I_G = −1 mA/mm. The microwave performance of the devices was measured on-wafer using a load-pull system at a bias of V_G = −0.5 V and V_DS = 8 V. For a device with a gate width of 1 mm, its saturated CW output power, gain and PAE value at 10 GHz was 27.5 dBm (0.55 W), 8 dB and 48%, respectively. At this same set of bias conditions, the value of f_t and f_max was 40 and 80 GHz, respectively.     

基于阵列波导光栅的波分复用器件

阵列波导光栅波分复用 /解复用器有 N个输入端口和 N个输出端口 ,能同时传输 N2 路不同的光信号 ,除具有波分复用和解复用功能外 ,能灵活地与其它光器件组成多波长激光器、光路分插复用器、光路交叉连接器、波长路由器等波分复用器件 ,在光通信网络中有着广泛的应用前景。     

S波段波导同轴转换器的无源互调特性实验研究

通过专用无源互调(Passive Intermodulation,PIM)分析仪对S波段波导同轴转换器的PIM特性进行了研究.对S波段波导同轴转换器的原型器件进行了PIM测试,结果表明:在输入载波功率为40 dBm时其三阶PIM约为-56 dBm;从连接器的外导体镀层材料和内导体探针的结构设计两个角度对所测结果进行了解释,并通过改进实验予以验证;为进一步获得低PIM性能,依据低PIM设计的基本原理对S波段波导同轴转换器进行了设计加工及验证测试,测试结果表明在输入载波功率为43 dBm时其三阶PIM约为-114 dBm.所得结果对开展有关波导PIM特性实验研究、微波无源器件的低PIM设计具有借鉴意义.