直接电流注入与自由场照射之间等价性的评估

介绍了直接电流注入技术在导弹EMC性能测试中的具体应用。文中一方面从理论上分析了直接电流注入技术及其模拟测试装置,评价了直接电流注入技术代替自由场照射的可行性;另一方面通过导弹自由场照射的理论计算及试验测试,评价了直接电流注入技术代替自由场照射的有效性。为导弹的高EMC安全裕度测试提供了一个简单、经济、有效的测试方法。     

直接电流注入技术对高场强辐射场的模拟与实践

本文介绍了高场强电磁兼容安全裕度测试工具的一个替代技术:直接电流注入技术。文中通过理论计算和试验测试,分析和验证了直接电流注入技术中注入功率与产生场强的关系及直接电流注入技术模拟高场强辐射场的可行性,为进一步研究和应用直接电流注入技术提供了依据和基础。     

强光注入锁定半导体激光器的理论分析

通过速率方程建立了强光注入半导体激光器的理论模型,研究了注入光强与从激光器注入锁定频率范围的关系.结果表明,强光注入增大了半导体激光器的注入锁定范围.同时对半导体激光器进行了时间特性的数值模拟,计算结果表明,无论是强光注入还是弱光注入,激光器的输出最终都趋于稳定,通过强光注入锁定条件与弱光注入条件下的对比,得出强光注入能有效地抑制弛豫振荡,缩短达到稳定的时间.     

分布反馈激光二极管调制特性及线宽测量

本文介绍了利用光谱分析测量DFB LD调制特性的方法及装置。介绍了测量装置光路部分和电路部分的技术要点。对DFB LD的实测说明:注入DFB LD电流的变化不会引起注入载流子密度明显变化,进而不会由此引起光频率的变化。这种测量方法可方便而准确地测量使用DFB LD的光端机的直接光强调制深度。     

直接注入模式可见光和红外传感器的注入效率

固体成像传感器包括可见光CCD,IRCCD,CMOS和红外焦平面阵列,其信号由光电二极管经注入栅沟道直接输入到转移级是基本的注入模式.本文总结了近30年来的发展成果,阐述了直接注入效率的理论和基本公式,得出在取样频率低的情况下,增大注入栅的跨导和光电二极管的阻抗是提高注入效率的最有效方法;在光电二极管低阻抗的情况下,采用电流镜像直接注入新设计,其注入栅的跨导可趋于无限大,因而可使注入效率接近100%.分析了电路的新设计方法,研制了64元线列InSb电流镜像直接注入电路.初步测试表明,注入效率与理论分析接近.     

IR FPA读出电路电注入测试系统

利用电流注入方式可以方便地模拟光电流注入,从而对红外焦平面阵列读出电路进行参数测试.采用NI公司的MIO-16E-1数据采集卡,通过软件编程,低成本、高效率地实现了读出电路的参数测试系统.使用多帧统计计算的方法对读出电路阵列的均方根噪声、动态范围和非均匀性等参数进行了测试.测试结果表明成品率达到64%以上,该批合格管芯已成功用于成像实验.     

电流(注入)探头校准装置的研究

本文设计了电流(注入)探头校准装置。在对不同型号电流(注入)探头孔径内径的研究,以及对电流探头工作原理研究的基础上,对校准夹具结构的尺寸进行了分析与计算,设计出注入电流(注入)探头校准夹具,并通过实验数据与原厂数据进行了对比分析,验证了装置的可行性。     

超深亚微米工艺下的电路级耦合SET脉冲注入

超深亚微米工艺下在电路模拟器中使用独立电流源方法的单粒子瞬态(single event transient, SET)脉冲注入与实验结果有很大误差. 作者提出了一种基于二维查找表的耦合电流源注入的方法,并且基于开源的SPICE 代码实现. 该方法的计算结果与器件/电路混合模拟接近,而其计算时间远小于混合模拟. 该法与SPICE 集成,可以引入实验测量数据,适合于大规模组合电路的SET 错误率分析.     

超深亚微米工艺下的电路级耦合SET脉冲注入

超深亚微米工艺下在电路模拟器中使用独立电流源方法的单粒子瞬态(single event transient,SET)脉冲注入与实验结果有很大误差.作者提出了一种基于二维查找表的耦合电流源注入的方法,并且基于开源的SPICE代码实现.该方法的计算结果与器件/电路混合模拟接近,而其计算时间远小于混合模拟.该法与SPICE集成,可以引入实验测量数据,适合于大规模组合电路的SET错误率分析.     

低温高注入硅双极晶体管电流增益的定量模拟

本文考虑了基区复合电流，发射结空间电荷区复合电流，基区高注入引起的禁带变窄效应，Ｅａｒｌｙ效应，基区和发射区电导调制效应，有效基区展宽效应以及发射区电流集边效应，定量地模拟了硅双极晶体管电流增益在７７Ｋ和３００Ｋ时与集电极电流的关系，并且与实验结果相吻合，计算还表明在低温７７Ｋ时，电流增益的大注入效应由基区电导调制效应和发射区电流集边效应决定，而在３００Ｋ时则由有效基区展宽效应决定。     

Optical control of 14 GHz MMIC oscillators based on InAlAs/InGaAsHBTs with monolithically integrated optical waveguides

An In_0.52Al_0.48As/In_0.53Ga_0.47 As heterojunction bipolar transistor (HBT) with a novel integrated optical waveguide for light input has been developed. Detailed modeling is used to validate the design and simulate the coupling of light from the waveguide into the device. Fabricated waveguide-HBT devices exhibited cutoff frequencies of f_T=32 GHz and f_max=48 GHz with 56% of the guided light being converted to photocurrent. Fabricated MMIC oscillators operating at 13.9 GHz exhibited direct optical controllability in the form of optical tuning and injection locking. This is the highest reported frequency for direct optical injection locking in an HBT-based oscillator     

Direct determination of the pinch-off voltage of a depletion-mode field-effect transistor

A direct method of determining Vpfor a depletion-mode FET is presented and compared with the values determined from a square-law transfer characteristic, the output characteristic, and the cutoff of drain current. The accuracy of the direct method makes it a useful technique for the screening and matching of devices.     

Alpha cutoff frequency of junction transistors

The alpha cutoff frequencies of drift and diffusion transistors are analyzed and approximated by simple analytical expressions. The alpha cutoff frequency is determined in terms of the three major contributions: base-region transport cutoff, emitter cutoff due to the emitter capacitance, and the collector cutoff due to the base resistance and the collector capacitance. Denoting the respective cutoff frequencies by ω^*_c, ω_E and ω_c, and the resulting cutoff frequency by ω_c, it is found by computation that

In addition, a new expression is given for the base transport cutoff.

The dependence of the frequency cutoff on the emitter current is also discussed for the current range where the built-in electric field is partially washed out by the high concentration of minority carriers injected into the base. A calculation is presented for the current level at which there is a maximum in the alpha cutoff.

Experimental data are compared with the calculations.     

Dynamic properties of AlGaAs vertical cavity surface emitting lasers with active region based on submonolayer InAs insertions

It has been shown that the use of submonolayer InAs insertions as an active region of AlGaAs vertical cavity surface emitting lasers make it possible to attain resonant frequencies as high as 17 GHz. In this case, single-mode devices with a smaller diameter of the current aperture make it possible to attain higher frequencies at lower current densities than those of multimode devices with a larger aperture diameter. The maximum error-free data transmission rate in the direct modulation mode in NRZ format is 20 Gb/s and is limited by the parasitic cutoff frequency. The high resonant frequency suggests that further optimization of the device design, directed to decreasing the electrical capacitance and resistances, the data transmission rate in lasers based on submonolayer insertions can be increased to 40 Gb/s.     

基于地-线缆耦合的感应电流分析*

高功率、大强度电磁波照射,是飞机在电子对抗中实施电磁干扰的重要手段。在实验室通过电流钳对线缆进行电流注入,从而达到模拟飞机系统间电磁干扰试验的目的。如何从理论上分析照射场在电缆上所感应的电流,是飞机系统间抗扰度实验的重要环节。文章利用有源传输线理论,建立了线缆-大地耦合模型,给出了线缆电流分布与大地电导率、地-线缆高度、线缆长度、线缆两端阻抗以及照射场的频率、幅度等多参数的关系;同时还进行了实测验证。结果表明,理论分析与实测结果基本一致,这为飞机系统间电磁干扰试验的实施提供了必要的理论和数据基础。     

High-gain, high-speed InP/InGaAs double-heterojunction bipolartransistors with a step-graded base-collector heterojunction

We show that by using InP for the emitter and collector layers, and a thin high-doped base layer, it is possible to achieve both a high DC current gain and a high maximum frequency of oscillation. We have fabricated InP/InGaAs double heterojunction bipolar transistors (DHBT's) with cutoff frequencies f_T and f_max of 92 and 95 GHz, respectively, with a DC current gain of over 100. The maximum cutoff frequencies were 107 and 104 GHz     

An efficient method for calculating cutoff frequencies in optical fibers with arbitrary index profiles

An accurate and simple method of calculating the cutoff frequencies of scalar modes in a fiber having an arbitrary refractive-index profile, including discrete numerical data from profile measurements, is proposed. First, the cutoff problem is transformed into a general matrix eigenvalue problem and then cutoff frequencies as the eigenvalues of a real symmetric matrix are evaluated. Representative test examples have been computed to illustrate the accuracy, reliability, and efficiency of the algorithm proposed.     

Comparison of AlGaN/GaN MSM Varactor Diodes Based on HFET and MOSHFET Layer Structures

In this letter, the performance of AlGaN/GaN-based metal-semiconductor-metal (MSM) varactor diodes based on HFET and MOSHFET layer systems is investigated. Passivated HFET MSM devices are coated with a 10-nm-thick SiO₂ layer between the electrodes; in MOSHFET-based diodes, this layer is also used as an insulator underneath the gate. Device fabrication uses standard HFET fabrication technology, allowing easy integration in monolithic microwave integrated circuits. Devices with different electrode geometry are characterized by direct current and by S-parameter measurements up to 50 GHz. The HFET-based varactors show capacitance ratios up to 14 and cutoff frequencies up to 74 GHz. The MOSHFET-based devices, on the other hand, show lower capacitance ratios and poorer stability because of the insulation layer between electrodes and semiconductor     

A Combined Method for Dielectric Waveguides Using the Finite-Element Technique and the Surface Integral Equations Method

A combined method employing a finite-element technique in the H/sub x/ - H/sub y/ formulation and the surface integral equations method is proposed to treat the propagation characteristics of inhomogeneous waveguides with single or multiple claddings. The significant features of this combined method are that it does not suffer from any kind of spurious modes, which have been troublesome in applying the finite-element technique to waveguides and it is also capable of treating the cutoff frequencies of arbitrarily shaped, inhomogeneous dielectric waveguides with a single cladding, which is perhaps original. Furthermore, the proposed method is convenient in treating propagation constants close to cutoff and in handling coupled waveguides. Numerical results of inhomogeneous elliptical waveguides, diffusion waveguides, and the corresponding directional couplers are presented, including the cutoff frequencies of the elliptical waveguides.