HIRF环境机载单芯电缆电磁敏感特性仿真研究

基于EMA 3D全波时域有限差分技术和MHARNESS多导体传输线技术,研究了多种机载单芯电缆的布线结构及其趋肤效应对高强度辐射场环境下场线耦合效应的影响.根据ARP 5583A低电平扫描电流测试要求设置仿真环境,计算得到机身内部折叠、弯曲、盘曲和趋肤效应等电缆模型在高强度辐射场环境下的感应电流及其传递函数.研究表明单芯线简化模型仅能在有限条件下保证仿真精度,电缆布线结构和趋肤效应对高强度辐射场条件下场线耦合效应的影响具有一定规律性.     

基于新型半圆形电极金属-半导体-金属紫外光探测器的光电耦合优化

本文使用数值仿真器ISE-TCAD建立了新型半圆形电极金属-半导体-金属紫外探测器器件模型并研究了该探测器的器件特性。通过对新型半圆形电极结构探测器,传统结构探测器以及实验数据的全面对比验证了模型的正确性。其结果表明了该探测器的性能提升并说明了建立的物理模型对预测这种新型结构探测器性能增强而言是合适的。此外,通过调节该器件的结构参数实现优化目的,优化结果表明半圆形电极半径为2 μm, 电极间距为3 μm的探测器在290 nm具有峰值响应度0.177 A/W ,相应的外量子效率超过75%, 同时在0.3 V 偏压条件下归一化光暗电流对比度达到1.192E11 1/W。这些特性表明半圆电极金属-半导体-金属紫外光电探测器具有优异的光电集成应用前景。     

机载VHF通信电台闪电间接效应试验与失效分析

以某型甚高频（VHF）通信电台为试验对象开展了闪电间接效应试验及失效分析。试验结果表明,通信电台的音频响应、谐波失真、发射功率、频率稳定度和调制深度对闪电电磁脉冲的敏感性较低,而接收灵敏度较为敏感,接收灵敏度的显著退化可作为VHF通信电台在闪电作用下发生失效的典型判据之一,VHF通信电台接收功能较发射功能更容易受到闪电影响。设备失效分析表明,闪电作用下VHF通信电台发生失效的主要机理为射频前端低噪声放大器失效和射频前端滤波器对地电感器与电容器熔融烧毁。     

空压机变频调速控制技术的应用

正空压机就是空气压缩机。空压机是工业现代化的基础产品,提供气源动力,是气动系统的核心设备机电引气源装置中的主体,是将电动机的机械能转换成气体压力能的装置,是压缩空气的气压发生装置。空压机是大的耗能设备,下面以现场实际为例,介绍在变频器和可编程序控制器(PLC)配合下,应用变频调速控制技术降低空压机能耗的方法。1原系统存在的问题某压缩空气站共有两台电动机功率为     

Two-dimensional numerical computation of the structure-dependent spectral response in a 4H-SiC metal-semiconductor-metal ultraviolet photodetector with consideration of reflection and absorption on contact electrodes

A two-dimensional model of a 4H-SiC metal-semiconductor-metal(MSM) ultraviolet photodetector has been established using a self-consistent numerical calculation method.The structure-dependent spectral response of a 4H-SiC MSM detector is calculated by solving Poisson’s equation,the current continuity equation and the current density equation.The calculated results are verified with experimental data.With consideration of the reflection and absorption on the metal contacts,a detailed study involving various electrode heights(H),spacings (S) and widths(W) reveals conclusive results in device design.The mechanisms responsible for variations of responsivity with those parameters are analyzed.The findings show that responsivity is inversely proportional to electrode height and is enhanced with an increase of electrode spacing and width.In addition,the ultraviolet (UV)-to-visible rejection ratio is > 103.By optimizing the device structure at 10 V bias,a responsivity as high as 180.056 mA/W,a comparable quantum efficiency of 77.93%and a maximum UV-to-visible rejection ratio of 1875 are achieved with a detector size of H = 50 nm,S =9μm and W = 3μm.     

Influence of the external component on the damage of the bipolar transistor induced by the electromagnetic pulse

A study on the influence of the external resistor and the external voltage source during the injection of the electromagnetic pulse(EMP) into the bipolar transistor(BJT) is carried out.Research shows that the increase of the external resistor R_b at base makes the burnout time of the device decrease slightly,the increase of the external voltage source V_(be) at base can aid the damage of the device when the magnitude of the injecting voltage is relatively low and has little influence when the magnitude i...     

一款航空VHF限幅器的设计与测试

为提高航空甚高频(VHF)通信设备的电磁防护能力,提出了一种基于PIN二极管的限幅器。采用先进设计系统(ADS)仿真研究了不同二极管级数对限幅器插入损耗以及限幅性能的影响,设计了一款由PIN对管并联结构、集总参数定向耦合器、整流电路与匹配电路相结合的半有源式限幅器,通过将部分干扰信号转变为直流的方式,为二极管提供偏置电压,降低限幅器的限幅电平。性能测试结果表明,在118~136 MHz的频率范围内,半有源式限幅器的插入损耗小于1 dB,输入输出端口的回波损耗大于20 dB,限幅电平小于7.5 dBm,功率容量大于25 dBm,实现了低插入损耗与高限幅性能。     

应用于北斗L、S频点的新型双频滤波器设计

提出了一种应用于北斗短报文波段（即L和S频点）的背靠背E形双频滤波器设计。该滤波器由两对公共馈电的背靠背E形谐振器并联组成,上方为背靠背E形的微带阶跃阻抗谐振器,下方为背靠背E形的缺陷阶跃阻抗谐振器。通过等效阻抗分析、表面电流仿真、参数优化得到滤波器的结构,滤波器尺寸为34 mm×21 mm×0.762 mm。实测结果表明,该滤波器的两个中心频点分别为1.62 GHz和2.53 GHz,相对带宽分别为8%和3%,带内插入损耗均小于2.2 dB,回波损耗均大于11.8 dB,相邻通带间的隔离度大于15 dB。测试结果与仿真结果基本吻合。     

雪崩PIN二极管中的电流丝运动

The motion of current filaments in avalanching PIN diodes has been investigated in this paper by 2D transient numerical simulations.The simulation results show that the filament can move along the length of the PIN diode back and forth when the self-heating effect is considered.The voltage waveform varies periodically due to the motion of the filament.The filament motion is driven by the temperature gradient in the filament due to the negative temperature dependence of the impact ionization rates.Contrary to the traditional understanding that current filamentation is a potential cause of thermal destruction,it is shown in this paper that the thermally-driven motion of current filaments leads to the homogenization of temperature in the diode and is expected to have a positive influence on the failure threshold of the PIN diode.