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991.
Tzong-Lin Wu Hung-Chun Chang 《Lightwave Technology, Journal of》1995,13(9):1926-1934
Based on vectorial formulations which combine the surface integral equation method and the finite-element method, a novel numerical approach is proposed for calculating the dispersion coefficients of dual-mode elliptical-core fibers with arbitrary refractive index profiles. By differentiating the original formulations involving the propagation constant β and the guided mode fields Hx and Hy once and twice with respect to the normalized frequency V, the new formulations for {dβ/dV, dHx/dV, dHy/dV} and for {d2β/dV2, d2 Hx/dV2, d2Hy/dV2 } are obtained respectively. Once {β, Hx, Hy } is solved through the eigenvalue procedure which dominates the computing time, only a few matrix manipulations are required to obtain {dβ/dV, dHx/dV, dHy/dV} and {d2β/dV2, d2Hx/dV2 , d2Hy/dV2}. Some numerical examples are examined to see the influence of different refractive index distributions with dips on the dispersions of the four nondegenerate LP 11 modes for elliptical-core fibers 相似文献
992.
A new simplified threshold-voltage model for n-MOSFETs with nonuniformly doped substrate and its application to MOSFET's miniaturization 总被引:1,自引:0,他引:1
Jiin-Jang Maa Ching-Yuan Wu 《Electron Devices, IEEE Transactions on》1995,42(8):1487-1494
The formulation, verification, and application of a new simplified 2-D threshold voltage model for n-MOSFETs with nonuniformly doped substrate profile are provided, in which the averaged normal field at the Si/SiO/sub 2/ interface in the active channel is quoted from a simplified solution of two-dimensional Poisson equation using the Green function technique. Starting with the expression of this average normal field, a simple threshold-voltage model for short-channel n-MOSFETs with nonuniformly doped substrate profile is explicitly expressed in terms of device structures and terminal voltages by considering parabolic source-drain boundary potentials. Moreover, the effects of the junction depth on the threshold voltage are examined in detail. It is shown that the DIBL effect cannot be completely eliminated by simply increasing the substrate doping concentration. Comparisons among developed model, 2-D numerical analysis, and experimental data have been made and the accuracy of the developed analytical model has been verified. In addition, a direct extension of our model to the case of uniformly doped substrates leads to a new constraint equation for device miniaturization.<> 相似文献
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器件尺寸按比例缩小是实现超大规模集成电路的有效途径,但寄生和二级效应却将器件限在一定的水平,本文在对比分析常温与低温下小尺寸器件效应的基础上,重点研究了MOS器件亚阈特性对器件性能及按比例缩小的影响,并根据低温工作的特点,提出了MOS器件一种低温按比例缩小规则,该原则对低温器的优化设计,从而更大程度在提高电路与系统性能具有重要的指导意义。 相似文献
996.
A new millimeter-wave omnidirectional dielectric rod metallic grating antenna is investigated theoretically and experimentally, in this paper. The radiation characteristics of the antenna are carefully investigated by a rigorous formulation for the TE01-mode and TM01-mode excitation in the Ka-band frequency range. Based on the analysis, an omnidirectional antenna excited by the TE01 mode is designed and measured. The measured results are compared with theoretical predictions and good agreement is found. Extensive numerical results are given to establish some useful guidelines for the design of the omnidirectional antenna 相似文献
997.
用于X光激光实验的反射式线聚焦光学系统的设计和分析 总被引:1,自引:1,他引:0
基于三维光线追迹的象差计算,对卢瑟福实验室用离轴球面反射线聚焦系统作了分析。然后,首次提出了用于X光激光实验的两类新的反射式线聚焦构型,即反射式光楔列阵和光锥列阵系统,并作了计算。最后,对所得结果作了比较和讨论。 相似文献
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