C波段有源微波冷噪声源设计及其性能分析

本文在介绍国内外有源微波冷噪声源技术发展的基础上,分析了有源微波冷噪声源的工作原理和关键技术.提出了一种有源微波冷噪声源设计方法,重点分析了设计过程中的关键环节对噪声源性能产生的影响.采用pHEMT型场效应管研制了C波段有源微波冷噪声源器件,并对该器件的性能进行了测试和分析.     

基于宽带匹配技术的C波段宽带有源微波冷噪声源设计

针对微波辐射计在同一频段内多通道定标时对稳定宽带低温定标源的需求，结合有源微波冷噪声源的工作原理和宽带匹配技术，提出了一种C波段宽带有源微波冷噪声源的设计方案，并对传统匹配网络结构进行了改进，从而显著地提升了器件的工作带宽，最终使用Avago公司的ATF38143型场效应管设计了一款C波段宽带有源微波冷噪声源。经测试，在常温条件下，该器件在中心频点为6.8 GHz,带宽为1 GHz的范围内输出的最低噪声温度为150.31 K,可应用于多通道C波段微波辐射计的定标工作。同时分析了该器件输出噪声温度受直流偏置电压、环境温度变化的影响，分析结果有助于具体工程应用。     

复合负反馈技术在宽带有源微波冷噪声源中的应用

针对C波段宽带有源微波冷噪声源设计中输出低温噪声性能与工作带宽的矛盾,文中选用Avago公司的ATF38143型GaAs基赝掺杂高电子迁移率晶体管(pHEMT)设计了一款C波段宽带有源微波冷噪声源。采用串、并联负反馈电路拓扑结构,在保证低温噪声输出性能的同时提升了工作带宽,其中心频点为6.95 GHz,工作带宽为1.3 GHz,相对带宽为18.7%,常温条件下带内输出最低噪声温度为141.62 K,工作频段可覆盖C波段微波辐射计中心频点为6.60 GHz、6.93 GHz、7.30 GHz的三个通道。     

基于小波分析的汽车噪声源识别

本文提出了一种利用车辆行驶时产生的声音信号进行汽车噪声源识别的新方法。对所采集的车辆行驶时的声音信号,运用小波变换对信号进行处理,找出汽车噪声主要集中的频段,通过与汽车各噪声源位于的频段进行比较就可以较为准确地找出汽车的主要噪声源,并通过实验论证了上述方法的可行性。     

用于雷达接收机检测的平面固态噪声源

设计了集成固态噪声源以测得雷达接收机的增益和噪声系数。设计采用国产噪声二极管开发平面集成固态噪声源用于接收机性能检测,包括噪声二极管集成、耦合器、驱动开关电路等。研究了平面集成固态噪声源超噪比(ENR)的测量方法,以及接收机噪声系数和增益的计算公式。固态噪声源和接收机电路无缝集成,极大减小了体积质量。设计的噪声源实现了28 dB的超噪比,较好地满足了接收机的检测要求,自检误差在可接受范围内。本设计通过了各类环境试验,并在实际产品中得到应用,取得较好的效果。     

军用电子元器件检测筛选中噪声源的设计

为解决传统军用电子元器件检测筛选中噪声源设计功率谱密度低的问题,优化设计军用电子元器件检测筛选中噪声源.采集噪声源辐射多元数据,拟合噪声源数据中白噪声与1/f噪声,确定噪声源辐射边界条件,提取检测筛选中噪声源背散射系数,完成军用电子元器件检测筛选中噪声源的设计.设计实例分析,结果表明,实验组噪声源功率谱密度显著高于对照...     

单脉冲雷达跟踪噪声源跟踪误差原因分析

自卫式噪声干扰机装载于被保护平台,因此噪声与目标回波来自同一方向,从角跟踪原理分析,单脉冲雷达可以通过跟踪噪声源达到跟踪目标的目的。本文仿真了单脉冲雷达跟踪噪声源,最后得出了影响跟踪误差的一些因素。     

单脉冲雷达跟踪噪声源跟踪误差原因分析

自卫式噪声干扰机装载于被保护平台，因此噪声与目标回波来自同一方向，从角跟踪原理分析，单脉冲雷达可以通过跟踪噪声源达到跟踪目标的目的。本文仿真了单脉冲雷达跟踪噪声源，最后得出了影响跟踪误差的一些因素。     

传导EMI噪声源内阻抗测量研究

基于传导电磁干扰产生机理,对传导 EMI 噪声源阻抗分析仪内阻抗测量的基本原理进行分析,并对比三种噪声源测量方法。利用插入损耗法对某一开关电源进行实际测试,给出了测试结果。     

相干技术和噪声源识别的实验研究

本文介绍了相干技术的基础知识，导出用相干函数法和偏相干函数法进行噪声源识别的方法，给出了对空压机站和轿车中噪声源识别的实验和分析结果，最后讨论了测量误差。     

An Active "Cold" Noise Source

An active circuit which behaves like a "cold" noise source is described. The circuit which uses a gallium arsenide FET is given the name COLFET. The appropriate theory is developed and practical circuits described using the circuit. Equivalent noise temperatures of less than 50 K have been measured for a 50-omega source at 1400 MHz.     

一种基于倍频技术的低相噪X波段频率源设计

为得到低相噪的X波段微波信号,运用微波倍频技术的原理设计了一种频率源。分别针对双极晶体管和场效应管倍频电路进行了具体分析和工程调试。最终完成的频率源实现了低相噪性能,相噪指标为-87 dBc@100 Hz,-102 dBc@1 kHz,-110 dBc@10 kHz。测试结果表明倍频电路除损失理论上的相位噪声外,基本不附加噪声。     

A functional GaAs FET noise model

It is the purpose of this paper to develop a theory upon which the design of low noise FET amplifiers can be based. This is not a fundamenta model of the noise mechanisms in GaAs FET's, but rather, an endeavor to relate physically measurable device capacitances and resistances to the device noise figure and optimum noise source impedance. I will be shown that the noise performance of an FET can be adequately described by two uncorrelated noise sources. One, at the input of the FET, is the thermal noise generated in the various resis, tances in the gate-source loop. This noise source is frequency dependent and it can be calculated from the equivalent circuit of the FET. The second noise source, in the Output of the FET, is frequency independent, and not recognizably related to any measured parameters. This output nise is a function of drain current and voltage. The decomposition of the FET noise into two uncorrelated sources simplifies the design of broad-band low noise amplifiers. Once the equivalent circuit of a device and its noise figure at one frequency are known, the optimum noise source impedance and noise figure over a broad range of frequencies may be calculated. For the device designer this model also may be helpful in balancing input-output noise tradeoffs.     

C波段低噪声放大器设计的要点

介绍了用微波工作室软件对C波段低噪声放大器的设计及调试.设计制作的C波段低噪声场效应管放大器,采用全微带匹配网络,利用NEC公司生产的场效应管N32584C,两级级联,用微波工作室软件进行设计、仿真和优化,实现在4.4～5.1GHz范围内增益30dB左右,噪声系数小于0.8dB.用Prote199SE画印制板,该放大器制作在聚四氟乙烯基板上.     

WZ541型砷化镓低调频噪声振荡晶体管

本文报道一种具有新颖“Γ”形栅结构的砷化镓振荡场效应晶体管,它不但具有较低的调频噪声,而且具有相当高的频率稳定度,是微波固态源较为理想的振荡器件。     

Improvement in the tetrode FET noise figure by neutralization and tuning

The noise figure of the tetrode FET is calculated, and it is shown that for frequencies near the cutoff frequency of the FET a considerable improvement in noise figure is possible by neutralizing the drain-gate capacitance C/SUB dg/ of the first half of the tetrode and by tuning the interstage network between the first and second half of the tetrode FET. To make this improvement possible, the tetrode FET must be provided with one extra lead connecting drain 1 + source 2 to the outside. The improvement is demonstrated for an FET cascode circuit.     

Noise performance of gallium arsenide field-effect transistors

After a brief review of the noise-generating mechanisms intrinsic to the GaAs FET, an enumeration is given of the various parasitic elements associated with the FET which affect the noise performance. These elements include, among others, the gate metallisation and source contact resistances, drain-gate feedback capacitance, and source lead inductance. Numerous graphs are presented to illustrate the effects of these elements and the various design parameters on the noise performance. A comparison is made between the theoretically predicted and the measured noise performance of microwave GaAs FET's. The best state-of-the-art noise performance as reported by various laboratories is illustrated graphically for single-stage and multistage FET amplifiers. Finally, some speculation is attempted in regard to the possible reductions in noise figure to be expected from technological and design improvements of GaAs FET's.     

Microwave MESFET Mixer

GaAs metal-semiconductor FET's (MESFET) are developed for use in amplifiers at microwave frequencies. The FET has a Schottky barrier between the gate and source, operating in the same manner as a Schottky-barrier diode. If the Schottky barrier is used as a mixer, the IF signal is generated and simultaneously amplified by the FET itself. Thus a mixer with IF preamplifier can be realized. In this paper the theoretical and experimental results of a FET mixer are described. In such operations, the conversion loss in the freqnency conversion alone is large due to the high series resistance of the Schottky barrier. However, the overall FET mixer has a "conversion gain" because the IF gain of the FET is made large. The experimental conversion gain is 6 dB at the RF frequency of 10.8 GHz and the IF frequency of 1.7 GHz. The noise figure of the FET mixer is at present large (15 dB, for example), due to large conversion loss in the frequency conversion.     

数字T/R组件噪声系数测量

系统性地讨论了数字T/R 组件噪声系数的测量方法。详细分析了Y 因子法、冷源法的系统误差来源,给出了推导过程及修正方法。系统误差主要来自于环境温度对噪声源以及矩阵开关、测试电缆等陪试品的影响。定量分析了随机误差与I/Q 数据点数的关系。提出了电磁干扰环境下测量噪声系数的测试建议。提出的测量方法及修正方法可广泛应用于相控阵雷达数字T/R 组件噪声系数的测试。