A novel ultracompact two-mode-interference wavelength division multiplexer for 1.5-/spl mu/m operation

A novel ultracompact 2/spl times/2 wavelength division multiplexer (WDM) for 1.55-/spl mu/m operation based on highly dispersive two-mode interference (TMI) was designed, theoretically modeled, and verified using a finite-difference-time-domain (FDTD) method. A two-moded waveguide assisted with a dispersive tooth-shaped grating provided a mode-dependent reflection band of central wavelength at 1.55 /spl mu/m. The wavelengths of 1538 and 1572 nm that were at the band edges and had the lowest reflection losses and relatively high dispersion were selected for wavelength multiplexing. The result showed that the wavelengths were separated by grating dispersion in a coupler length of 75 /spl mu/m which was much shorter than the required length of 1.1 mm in a regular TMI multiplexer of no grating. Insertion loss of about 1.7 dB and channel contrast of about 12 dB were achieved.     

高压RESURF LDMOS开态击穿模型

建立了高压RESURF LDMOS的开态击穿模型.该模型考虑了载流子的速度饱和现象和寄生双极性晶体管的影响,获得了开态下LDMOS漂移区中的电场分布.基于该模型可以计算出高压 RESURF LDMOS的电学SOA.数值模拟和实验结果部分验证了模型的正确性.该模型有助于深入理解LDMOS开态击穿的物理过程,可用于指导高压LDMOS的设计.     

In掺杂对ZnO薄膜结构及光学特性的影响

通过射频反应溅射法在硅衬底上制备了具有c轴择优取向和小晶格失配的In掺杂ZnO薄膜.在室温下测量样品的光致发光(PL)光谱,观察到波长位于415nm(3.02eV)和430nm(2.88eV)附近的蓝紫发光双峰.研究了不同In掺杂量对ZnO薄膜的结构和发光特性的影响.当In片面积为靶总面积的3%时,样品具有高度的c轴择优取向和较小的晶格失配(0.16%);同时在PL谱中观察到波长位于415nm(3.02eV)和433nm(2.86eV)处的强蓝紫光双峰.     

双极晶体管△Vbe瞬态热阻测试法精度修正

对双极型晶体管△VBE瞬态热阻测试法中晶体管壳温波动和测量延迟时间的误差进行了分析,提出了提高测试精度的误差修正方法.以3DK457(F0金属封装)双极晶体管为实验对象进行了研究,结果表明:晶体管瞬态热阻△VBE修正测试方法与红外扫描热像法和标准电学法相比较在保持较高测量精度的前提下,测试成本低,测量效率高.     

Nanomechanical characterization of polymer using atomic force microscopy and nanoindentation

The nanomechanical characteristics of polycarbonate (PC) polymer were investigated by atomic force microscope (AFM) and nanoindentation. Scratching, wear properties, hardness and Young's modulus were obtained. The relationships between scribing feed and speed, surface depth and roughness and applied load were also investigated. The results indicated that as the applied load was increased, the furrow depth and the surface roughness increased. When the scribing feed was increased, the depth and roughness decreased. Increasing the furrow speed also decreased the surface roughness. The applied load is more significant than the scribing speed on the material removal rate. In addition, the Young's modulus and hardness of the polycarbonate material were 1.8 and 0.2 GPa, respectively.     

Effect of extrinsic impedance and parasitic capacitance on figure of merit of RF MOSFET

This paper investigates the impact of source/drain impedance, gate-to-bulk capacitance, and gate resistance on device properties from 0 to 50 GHz for 0.13-/spl mu/m MOSFETs. Better device characteristics (g/sub m/ and C/sub gg/) can be found on MOSFETs with lower metal (or source/drain) resistance. But the best frequency characteristics (f/sub T/ and f/sub max/) occurred on MOSFETs with medium metal (or source/drain) resistance due to the increased interconnection capacitances. For radio frequency MOSFETs with finger-gate structure, better high-frequency behavior occurred on devices with medium finger-gate width W/sub f/ because of the tradeoff between gate (or source/drain) resistance and parasitic capacitance.     

Parallel multilevel fast multipole method for solving large-scale problems

The Multilevel Fast Multipole Method (FMM) is a well-established method and can be applied to solve electromagnetic (EM) scattering problems. Compared with other traditional methods, it requires less computational time and memory. However, constrained by a single processor's speed and memory limitations, the problem size that can be solved by serial implementation is still relatively small. For a million-unknown target, the computational time on a single processor is intolerable, and memory could be easily exhausted. Parallel-computing technology, which can utilize multiprocessors, provides an efficient way to solve electrically large-scale EM problems. This paper will focus on discussing the parallel methodologies applied to a multilevel FMM code, as well as demonstrating the computational efficiency of the parallel approach.     

EDA课程建设与创新型人才培养

EDA课程是教育部认定的电子类专业核心课程之一,具有软硬件知识更新速度快和应用面广等特点.本文依托中央与地方共建实验室和校级教育教学改革项目,开展EDA课程建设.我们从培养学生的实践和创新能力入手,建立了开放式的共享实验教学平台,构建了科学合理的三层次教学内容,通过多样化的教学手段,充分调动学生积极性,已收到很好的建设...     

具有片上多段基准源的14位宽温度范围高SNDR全差分逐次逼近型模数转换器

介绍了一种带有片上多段带隙基准源的14位低功耗自定时全差分逐次逼近型模数转换器。采用一个在-40到120℃温度范围内具有1.3ppm/℃温度系数的片上多段带隙基准电压源来为逐次逼近型模数转换器提供高精度基准电压源。设计中用格雷码代替二进制编码来减少衬底噪声从而增加整个系统的线性度。采用自定时位循环来增加时间利用率。该14位模数转换器利用TSMC 0.13μm CMOS工艺流片。该逐次逼近型模数转换器在室温2M/s 转换速率条件下能够获得81.2dB SNDR (有效位数13.2) 和85.2dB SFDR,并且在2M/s转换速率下在-40到120℃温度范围内能够保持12位以上有效位数。     

基于有限元模型的超声切割刀优化设计

超声切割刀在材料加工领域中有广泛的应用前景,可用于切割各种复合材料等硬脆材料。该文利用ANSYS有限元分析软件建立超声切割刀的有限元模型,对其进行模态分析和谐响应分析。仿真结果显示,超声切割刀在40kHz频率附近存在轴向纵振模态,其振动节点位于安装环和压电陶瓷中心线上,符合设计要求。基于有限元模型研制超声波切割刀,通过阻抗分析仪与激光多谱勒测振仪对换能器的固有频率与响应进行测试,获得的超声切割刀阻抗曲线平滑,谐振频率为40.261kHz,设计误差为0.83%,最大振幅达到14.52μm,结果与有限元计算相互吻合。