On-wafer photoconductive sampling of MMICs

A practical technique for the on-wafer characterization of the high-frequency response of a MMIC was developed, using photoconductive (PC) sampling. It provides S-parameter measurement with broadband, high sensitivity, and accurate calibration. In addition, due to its inherent broadband signal generation on the wafer, high-frequency information of the circuits can be extracted merely by using DC probes. Starting from a hybrid testing configuration, the compatibility of PC switch fabrication with the MMIC production process is demonstrated. In this phase, 40-dB dynamic range in the S-parameter measurement was achieved. The success motivated the monolithic integration of the PC switches onto the MMIC. Efforts were made to reduce the size of the optical test structure. Good agreement between a conventional network analyzer measurement and two optical testing results has been achieved, showing that built-in optical test structures can be designed to have comparable overall size with existing CPW test structures. The S-parameter characterization of a nonlinear transmission line is demonstrated     

基于myDAQ的直流电机PWM远程控制系统设计

提出了一种基于myDAQ的PWM远程控制直流电机调速与测量系统。采用LabVIEW开发平台,在上位机用图形化编程语言编制PWM控制信号,并通过myDAQ的模拟输出口将PWM信号送给直流电机驱动控制电路实现电机的调速,同时上位机启动、停止、转向等控制信号也通过myDAQ数字输出口送给驱动电路进而实现电机的起、停、转向控制。电机转速通过编码器测量并送至上位机,在上位机将会实时跟踪与显示电机运行状态以及PWM控制信号波形,利用LabVIEW的WEB发布技术将前面板发布至网络上进而实现运程控制。通过测试及分析,结果显示整个系统运行良好、稳定、实时性强。     

低频/甚低频电磁脉冲测量系统研究

为了准确地测量电磁脉冲（electromagnetic pulse,EMP）的波形,开展低频/甚低频（low-frequency/very low-frequency,LF/VLF）EMP的形成和传播机理研究,识别不同EMP的特征,并以此为依据来识别、确认雷电及核爆炸等现象,提出了一种高分辨率的EMP原始波形测量系统方案,同时针对LF/VLF这一较低的频段提出了一套有效的系统标校方法,实现了对EMP的连续、准确测量和快速有效判别,并能通过网络实时上传数据.系统采用正交环磁场天线和平板电容电场天线实现信号的接收,设计了低噪声高保真的信道调理电路和高速数据采集电路来实现信号的采集,利用高精度的授时模块为EMP信号标记时间戳,最后结合多点监测波形实现EMP定位估计.实测结果表明:该系统能够给出高分辨率、高精度的LF/VLF EMP波形;利用该系统组网可以实现远距离EMP源的定位,定位精度与目前近距离的定位手段相当.通过长期的运行,验证了该系统具有高可靠、低失真、判别准确、实时性强等特点.     

High-speed, 100+W RF switches using GaAs MMICs

A low-loss, inductive gate bias network structure which allows a very high stacking level of FET devices for high-power RF switching applications is reported. The design, implementation, and performance of S- and C-band SPDT switches based on this structure are described. Multiple GaAs MMIC chips integrated into a suspended-substrate hybrid circuit are used. At S-band, switch risetimes/falltimes of less than 40 ns and an RF power handling capability of 300 W CW have been demonstrated. This input signal level could be maintained during the switch state transitions (hot-switching), while being switched between the two output ports at rates of up to 500 kHz     

GaAs MMIC抗静电能力研究

用人体静电放电模拟器对以ＧａＡｓ ＭＥＳＦＥＴ为主要有源器件的ＭＭＩＣ的静电敏感度进行研究,叙述了在ＭＭＩＣ设计、工艺制作等环节防静电和提高ＭＭＩＣ抗静电能力的措施,采用这些措施后,低噪声ＭＭＩＣ静电损伤阈值达到５００～８００ Ｖ。     

Ku波段单片功率放大器设计与制作

介绍了一种Ku波段GaAs功率放大器芯片的研制过程。芯片采用电抗匹配电路结构,三级级联放大,末级采用多胞器件进行功率合成,实现了电路的高增益和所要求的功率输出;另外,还对元器件模型技术、GaAsMM IC测试技术等进行了相应描述。在芯片的研制过程中,利用ADS软件进行仿真及优化,利用电磁场仿真进行版图设计。在4英寸(100 mm)0.25μmGaAs PHEMT工艺线上完成芯片制作,在12.5～15.0 GHz的频率范围内,脉冲饱和输出功率Po大于34.7 dBm(脉宽100μs,占空比10%),功率增益Gp大于19.7 dB,功率附加效率PAE大于30%,功率增益平坦度小于±0.4 dB。该芯片可以应用到许多微波系统中。     

Beyond G-band: a 235 GHz InP MMIC amplifier

We present results on an InP monolithic millimeter-wave integrated circuit (MMIC) amplifier having 10-dB gain at 235GHz. We designed this circuit and fabricated the chip in Northrop Grumman Space Technology's (NGST) 0.07-/spl mu/m InP high electron mobility transistor (HEMT) process. Using a WR3 (220-325GHz) waveguide vector network analyzer system interfaced to waveguide wafer probes, we measured this chip on-wafer for S-parameters. To our knowledge, this is the first time a WR3 waveguide on-wafer measurement system has been used to measure gain in a MMIC amplifier above 230GHz.     

基于DSP的无功补偿控制系统采样电路的设计

针对目前配网中电压与电流较难实时测量的问题,详细介绍了MCR的无功补偿控制系统采样电路的设计思想,设计出基于DSP采样的硬件电路,对硬件电路设计上进行了优化,对硬件的可靠性详细的分析。由于滤波以及触发信号的时间基准问题,同时也设计了相位补偿硬件电路以及过零检测硬件电路。实验结果表明采样电路、相位补偿电路和过零检测电路解决了MCR的无功补偿控制系统中电压、电流采样问题以及晶闸管触发信号的时间基准问题。     

基于FPGA的多通道模拟信号源设计

针对航天测试领域对模拟信号源的设计要求,提出一种新的信号源实现方法。该方法借助计算机软件能实时编程生成波形数据,通过对波形重构电路,调理电路和多通道电路的合理设计,由FPGA控制逻辑实现波形重构和多通道输出。由于方波信号沿变时具有的特殊性,设计专门的方波产生电路,通过实验验证,对原先设计电路的阻尼特性加以改进,实现了方波信号高精度的可靠输出,满足技术指标要求。目前,该信号源已广泛应用于多项航天测试项目。     

基于PC104的电动投弹器检测系统电路设计与实现

介绍了一个基于PC104的数据采集与检测电路的设计,它完成A/D数据采集、D/A数字/模拟转换、数字量输入/输出、信号显示卡以及LCD显示器的控制等功能。PC104总线信号检测电路对于改进装备故障检测方式具有重大意义。通过对信号波形显示原理以及显示方法的分析,确定了具体的实际方案,完成了功能电路的设计;采用专用接口芯片结合CPLD的方法实现了PC104总线的接口协议以及逻辑控制电路;检测系统电路在实际测试过程中能稳定工作,满足设计指标要求。     

Linearised InGaP/GaAs HBT MMIC power amplifier with active biascircuit for W-CDMA application

A high linearity InGaP/GaAs heterojunction bipolar transistor (HBT) monolithic microwave integrated circuit (MMIC) power amplifier is demonstrated using a new structure for a bias circuit for wideband-code division multiple access (W-CDMA) application. A one shunt capacitor is added to a novel active bias circuit and acts as a lineariser improving input P_{1 dB} of 16 dB and phase distortion of 5.1° for the hybrid phase shift keying (HPSK) modulated signal at the 28 dBm output power; the lineariser showing no significant increase of signal loss and chip area. The two-stage HBT MMIC amplifier exhibits a power-added efficiency (PAE) of 37%, a linear power gain of 24.5 dB, and an output power of 28 dBm with an adjacent channel power ratio (ACPR) of -45 dBc, under a 3 V operation voltage     

A sophisticated analysis procedure for an MMIC phase shifter

This paper describes a new analysis procedure for a highpass and lowpass (HP/LP) filter type MMIC phase shifter consisting of switching GaAs MESFETs. This paper reveals that a specially designed large signal model for a switching MESFET, described by a gate bias dependent equivalent circuit, is the key to realizing an accurate nonlinear simulation of the HP/LP filter type phase shifter. The new analysis procedure realizes a highly accurate phase shifter analysis for both linear and nonlinear simulations. A comparison between the analysis results and measurement results for the phase shifter shows excellent agreement     

智能双折射率测量系统的研究与改进

针对SZY-1型双折射率测试仪存在的非自动化,系统老化引起的测量精度低等问题,结合电路模块化和程控技术,对原有测试系统的信号发生源和直流高压源部分进行了改造.硬件电路围绕STC89C52搭建,由单片机产生方波信号,并用按键控制其相位、占空比的大小,实时显示波形和数值,取代了原有硬件电路实现相位粗调和细调的方法.阐述了系统的软件设计流程,并对改造后的电路进行了测试,发现测量系统完全符合原电路原理,性能良好,具有较好的应用前景.     

X波段ISAR波形激励与失真补偿

论述一种X波段可扩充相控阵高分辨逆合成孔径雷达波形激励设计过程,分析了波形激励及其内单元电路的原理及指标分配方法,该波形激励采用调制器产生宽带线性调频(LFM)信号,且采用了倍频法提高激励带宽,突破了宽带信号产生及校正、宽带激励等宽带相控阵雷达系统的关键技术,解决了宽带、窄带系统的波形激励硬件共用问题,随整机进行外场实验,性能指标满足要求。     

基于LabVIEW的摩擦磨损试验机智能测控系统

利用虚拟仪器开发平台LabVIEW开发一种多功能摩擦磨损试验机智能测控系统。该智能测控系统以工控机为核心,集数据采集、数据处理、波形显示和试验环境控制为一体,实现了温度、速度、压力、力矩和摩擦系数的实时检测。利用LabVIEW内嵌的C语言子程序使系统具有灵活而又强大的数据处理能力,且能为以后的数据处理提供一个很好的平台。该试验机可更好地模拟现实工况条件,开展多种方式下的摩擦学试验研究。     

A W-band subharmonically pumped monolithic GaAs-based HEMT gate mixer

A W-band high electron mobility transistor (HEMT) subharmonically pumped (SHP) gate mixer is designed with fixed LO frequency operation. it is fabricated on a 4-mil substrate using 0.15-/spl mu/m GaAs pHEMT monolithic microwave integrated circuit (MMIC) process. the on-wafer measurement results show that the best conversion loss is about 4.7 dB in the W-band, as a 11-dbm 42-GHz low observable (LO) signal is pumped. To our knowledge, this is the first result on low conversion-loss W-band MMIC SHP HEMT gate mixer.     

DC－40GHzMMIC开关

ＤＣ－４０ＧＨｚＭＭＩＣ开关叶禹康，俞土法，伍祥冰（南京电子器件研究所，２１００１６）提要＊用微波单片集成电路（ＭＭＩＣ）技术设计制作了高隔离度、超快速ＤＣ－４０ＧＨｚＭＭＩＣ开关（ＳＰＳＴ）。开关采用串联、并联单元ＭＥＳＦＥＴ兼用的电路结构。芯片尺...     

DC－40GHzMMIC开关

ＤＣ－４０ＧＨｚＭＭＩＣ开关叶禹康，俞土法，伍祥冰（南京电子器件研究所，２１００１６）提要＊用微波单片集成电路（ＭＭＩＣ）技术设计制作了高隔离度、超快速ＤＣ－４０ＧＨｚＭＭＩＣ开关（ＳＰＳＴ）。开关采用串联、并联单元ＭＥＳＦＥＴ兼用的电路结构。芯片尺...     

X波段1.5WGaAsMMIC研究

介绍了Ｘ波段１．５Ｗ ＧａＡｓＭＭＩＣ的设计、制作和性能测试,包括ＭＥＳＦＥＴ大信号模型的建立、电路ＣＡＤ优化、ＤＯＥ灵敏度分析及Ｔ型栅工艺研究等。微波测试结果为： 在频率９．４～１０．２ＧＨｚ下, 输出功率大于３２ｄＢｍ , 增益大于１０ｄＢ。     

基于PSD的微位移测量系统研究

介绍了PSD的结构、特性和工作原理,设计了一种基于PSD探测器的微位移测量系统。针对PSD信号输出特点和实际应用要求,提出了基于PSD的微位移信号采集、处理和上位机通信系统。单片机通过ADS7864采集PSD的输出信号,处理后由RS232接口传给上位机,位移值在上位机界面显示,实现了对光斑微位移量的实时测量。实验结果表明,该系统响应速度快、测量精度高,可广泛应用于微位移测量领域。