Study on rectangular waveguide grating Slow-Wave Structure with cosine-shaped grooves

This paper focuses on a new rectangular waveguide grating Slow-Wave Structure （SWS） with cosine-shaped grooves and studies the propagation characteristics of the wave in the SWS. By using the approximate field-matching conditions, the dispersion equation and the coupling impedance of this circuit are obtained. The dispersion curves and coupling impedances of the fundamental wave are calculated and the influences of the various geometrical dimensions are discussed. The results show that the bandwidth of the cosine-shaped groove SWS is much wider than that of rectangular-shaped groove one. And reducing the groove width can broaden the frequency-band and decrease the phase-velocity, while increment of the groove-depth can also decrease phase-velocity. For above cases, the coupling impedance is more than 16Ω. The present analysis will be helpful on further study and design of the RF systems used in millimeter wave Traveling Wave Tube （TWT）.     

Preliminary study of 0.14 THz water surface clutter reflectivity at near vertical incidence angle

As the development of radar systems developed for the terahertz and higher millimeter region continues to grow, the interest in the water surface and land clutter at terahertz and higher millimeter frequencies continues to increase. An empirical model of sea clutter reflectivity is described firstly, which is valid at near vertical incidence and has small average absolute deviation compared to other empirical models. Simulated results of 0.14 THz sea clutter at near vertical incidence with this model are shown. An indoor test-bed is constructed in order to measure 0.14 THz water surface clutter reflectivity and an experiment is carried out. Initial experimental results are presented and compared to the simulation results, which partially verifies that the empirical sea clutter model still works at 0.14 THz.     

COHERENT RADIATION OF MILLIMETER WAVES GENERATED BY AN INTENSE ROTATING ANNULAR RELATIVISTIC ELECTRON BEAM

Properties of coherent radiation of millimeter waves generated by an intense rotating annularrelativistic electron beam(E-layer)which is from a cusp magnetic field are investigated.The linearizedVlasov-Maxwell equations are used to analyze the interaction between E-layer and resonators of themagnetron.The dispersion relation is deduced and numerical calculation is made.The results show that thefrequency of microwave radiation is ω_r(ω_r=lΩ〃 where Ω〃 is the electron relativistic cyclotron frequencyin the axial magnetic field;l is the azimuthal mode number,l=n+mN;N is the number of sideresonators,n=0,1,2,……N/2,m is any integer).The growth rate of radiation is still large enough even ifl is large.It is good for generating a millimeter wave radiation at low axial magnetic field.If the modes canbe controlled well,a tunable,high power millimeter wave device can be made.     

USE OF FINITE-DIFFERENCE TIME-DOMAIN METHOD FOR CALCULATING EM ABSORPTION IN LOSSY DIELECTRIC SCATTERER

The problem for calculating EM energy absorption by lossy dielectric scatterer ir-radiated by plane wave are discussed.The factors affecting the accuracy of computation arediscussed.The calculated results of EM energy absorption and its distribution in homogeneousand layered homogenous lossy dielectric spheres are presented,and a comparison of these resultswith analytical solution is given.The calculation is carried out for dielectric cylinder on conduct-ing ground as well,and the results are compared with the image theory.All the computationsshew that the finite-difference time-domain method can give satisfactory results.     

A millimeter wave linear superposition oscillator in 0.18 μm CMOS technology

This paper presents a millimeter wave （mm-wave） oscillator that generates signal at 36.56 GHz. The ram-wave oscillator is realized in a UMC 0.18 μm CMOS process. The linear superposition （LS） technique breaks through the limit of cut-off frequency （JET）, and realizes a much higher oscillation than Jr. Measurement results show that the LS oscillator produces a calibrated 37.17 dBm output power when biased at 1.8 V; the output power of fundamental signal is -10.85 dBm after calibration. The measured phase noise at 1 MHz frequency offset is -112.54 dBc/Hz at the frequency of 9.14 GHz. This circuit can be properly applied to mm-wave communication systems with advantages of low cost and high integration density.     

CHARACTERISTICS OF CYCLOTRON AUTORESONANCE MASER WITH A LARGE-ORBIT ELECTRON RING IN A PARTIALLY DIELECTRIC-LOADED WAVEGUIDE

The cyclotron autoresonace masers with a large-orbit electron ring in a dielectric-loaded waveguide have been analyzed.The stability properties are investigated self-consistentlyon the basis of the linearized Vlasov-Maxwell equations.The numerical results show that thedielectric liner can greatly reduce the energy of the electron beam,and a novel effective radiationdevice with low electron beam energy in the millimeter and submillimeter wave region have beenproposed.     

Adaptive Modulation and Power Control for throughput enhancement in cognitive radios

To regulate the transmit-power and enhance the total throughput, a novel Transmit Power Control Game （TPCG） algorithm and an adaptive Modulation TPCG （M-TPCG） algorithm which combine bandwidth allocation, adaptive modulation and transmit-power control based on Space Time Block Coding （STBC） OFDM-CDMA system are designed and a cross-layer framework of database sharing is proposed. Simulation results show that the TPCG algorithm can regulate their transmitter powers and enhance the total throughput effectively, M-TPCG algorithm can achieve maximal system throughput. The performance of the cognitive radio system is improved obviously.     

Numerical simulation of shock wave phenomena in hydrodynamic model of semiconductor devices

We propose a finite element method to investigate the phenomena of shock wave and to simulate the hydrodynamic model in semiconductor devices . An introduction of this model is discussed first. Then some scaling factors and a relationship between the changing variables are discussed. And then, we use a finite element method (P1-iso-P2 element) to discrete the equations. Some boundary conditions are also discussed. Finally,a sub-micron n+-n-n+ silicon diode and Si MESFET device are simulated and the results are analyzed. Numerical results show that electronic fluids are transonic under some conditions.     

A speaker driver for a single phase supply class G & I

A speaker driver applied to class G/classⅠwith a single phase power supply is presented.Gain expanding and compressing technology are employed in the signal processing circuit to optimize power dissipation.The circuit is implemented in 0.18μm N-well CMOS.Experimental results show that the speaker driver has a good audio sound quality and power efficiency.Less than 0.006%THD at a low power range and less than 0.4%at a medium power range can be obtained with a 1 kHz sine wave signal.Maximum output power of 360 mW can be gained at a load of 8Ω.The power efficiency is about twice that of a traditional class AB driver at the power range of 80 mW and shows more than 18%improvement at the higher output power range.     

箔条和箔片的性能特性及其应用和趋势

从箔条和箔片用于干扰雷达测和扰乱、迷惑、转移或者引诱进攻出发,详细论述箔条、箔条云及箔片、箔片云的雷达散射截面、带度、平移速度、下降速度及转动等情况,空间和时间我、水平和垂直极化性能、多普勒频移效应以及频谱展宽特性等,通过箔条和箔片有效成火控雷达实例,提出对抗火控雷达的三个重要因素及其采取的对策。     

"电路原理"与"信号与系统"课程的整合与优化

科学技术迅速发展,新兴学料不断增加,知识总量不断增长,迫使本科教育不断向着基础化方向发展,基础课程教学在本科教育中的地位愈来愈高。计算机技术的广泛应用,离散信号与系统的基础知识已是电气类各专业的必要的教学内容。因此基础课程要从根本上整体优化课程结构。本文提出了电气类专业“电路原理”与“信号与系统”课程教学改革方案,将两门课程教学内容进行整合与优化,并在实际教学过程中进行了教学试验,缩短了教学时间,提高了教学质量。     

压电／电致伸缩材料及驱动器的新技术与应用

压电／电致伸缩驱动器是一种广泛使用的驱动器,文章概括总结了几种压电／电致伸缩新材料的发展方向,同时还介绍了几种新型驱动模式和超声电机的研究动态,并对压电／电致伸缩驱动器的发展前景予以展望。     

日本广播电视天线及其相关技术的发展与探讨

在日本电视广播的发展过程中,电视信号技术、电视节目转播技术、发射机技术以及天线技术等发挥了不可替代的作用。这些技术在长达60多年的模拟电视广播中被大量的开发、使用,尤其是射频相关技术为日后地面数字电视广播的发展提供了重要参考。主要介绍了日本电视广播中该相关技术的发展,并进行了讨论。     

电压波动和闪烁的解析测量法及其应用与验证

文章介绍了针对特定电压变化特性的被测设备的、简单的、低成本的电压波动和闪烁的解析测量法,并将实际解析法测量计算结果与直接测量法结果进行了比较、验证,证明该方法切实可行,且符合标准规定的容差要求。     

“信号与系统”课程建设与教改的探索

信号与系统课程是高等院校电类专业一门重要的专业基础课程,本文以西安明德理工学院智能制造与控制技术学院的信号与系统课程建设与教学改革为例,介绍了我院在信号与系统课程资源建设和教学改革中的探索和实践。实践证明,本文提出的五维一体化线上线下课程资源建设和混合式教学改革能够有效推动教与学两个方面的变革,有效提高课程教学质量,为同类兄弟院校的同类课程建设和教学改革起到一定的借鉴作用。     

TD-SCDMA和WCDMA系统以及HSDPA的容量覆盖分析

作为3G的增强型技术的HSDPA已经越来越受到重视,在WCDMA系统网络规划中HSDPA的规划方法研究的较多。由于TD-SCDMA标准出现较晚,对应其引入HSDPA后的规划还不太成熟。本文分别阐述了两系统的网络规划的基本方法,分析探讨了其中的异同,从而更好地指导下一步TD-SCDMA无线网络规划。     

层次化跨区域SDN验证示范系统的设计与建设

软件定义网络（SDN）架构给网络带来了卓越的灵活性和可管理性。为了给新型SDN技术与应用提供大规模可行性验证试验床与试点部署平台,提出了依托于CERNET的层次化跨区域SDN 异地验证示范网络试验系统的总体架构,建设了9个城市、13个节点的SDN验证示范核心网与包含3个数据中心的接入网,并对基于SDN的vCPE智能专线业务、IPv4/IPv6过渡技术、流量监控调度应用和数据中心应用进行验证与示范。     

轻小型推扫视频一体化相机设计与验证

介绍了一种轻小型推扫视频一体化微纳遥感相机的综合优化设计思路。系统设计时综合考虑星地一体化处理,采用大F数RC系统降低产品光机体积重量;电子学采用商用货架产品加固技术实现高性能同时降低成本,星上数据处理采用数字TDI技术实现面阵相机推扫视频一体化成像,大幅提升成像效能。采用该方法设计的微纳遥感相机具备视频、推扫、条带等多种工作模式,满足不同应用场景需求。该技术在欧比特视频相机等微纳遥感载荷的设计及研制中进行了应用,在轨获取了高品质的视频及遥感图像,在商业遥感载荷市场具有广阔的应用前景。     

广电5 G传输及架构研究测试平台的构建与设计

根据广电5G未来建设的发展,结合当前传输和架构研究和测试的需求,提出搭建广电5G传输研究测试平台的意义,并对平台进行构建,最后对平台的各个组成部分进行了详细阐述。