Measurement of Losses in Noise-Matching Networks

The noise contribution of an input-matching network to a low-noise amplifier is equal to the inverse of the network's available gain. The available gain of various networks at 4 GHz was computed from high-accuracy S-parameter measurements. The available gain of a typical tuner was experimentally found to be a strong function of its tuning, which shows that "back-to-back" measurements of two tuners to obtain the loss of each tuner can be inaccurate. Measurement of the available gain of an amplifier's input-matching circuit is shown to give quick insight into its minimum noise contribution before the actual amplifier stage is built.     

微波器件噪声参数的测量方法

作为微波低噪声器件研制和应用的一项关键技术,噪声参数的测量工作引起行业的广泛关注。论述了噪声参数测量原理,研究了测量系统校准方法,分析了噪声源的反射系数、噪声温度,阻抗调配器的反射系数、S参数、增益,接收机的反射系数、噪声功率等20余项物理量对噪声参数测量的影响,对比了直接冷源法和简化冷源法在接收机传输增益测量中的优缺点,提出了改进型冷源法。最后给出了噪声参数测量不确定度主要影响量的归类分析,为下一步开展噪声参数不确定度评定工作奠定了基础。     

Determination of Microwave Transistor Noise and Gain Parameters through Noise-Figure Measurements Only

A novel method for measuring noise and gain parameters of linear two-ports solely from noise-figure measurements is applied here to perform noise and gain characterization of microwave transistors versus frequency and collector current in S-band. The method results in a simpler procedure and improved accuracy compared to conventional methods. In addition, a technique to estimate the loss of the input tuner of the measuring setup is presented, which yields a further improvement in accuracy. As experimental verification, the noise and gain parameters of a microwave transistor versus collector current in the 2-4-GHz frequency range are reported.     

微波晶体管参数的测量方法

本文用信号流国和矩阵方法分析了测量激彼晶体管S参数的三种方法，分别给出了10个和8个误差参数信号流图新的显式解。为各种型号的矢量网络分析仪测量做液晶体管S参数，提供了精确测试方法。     

GaN HEMT器件微波噪声模型参数提取

介绍了两种可以用于GaN高电子迁移率晶体管(HEMT)器件建模的噪声模型,Pu-cel等效电路噪声模型和Pospieszalski温度噪声模型.基于Pucel等效电路噪声模型,介绍了利用器件本征噪声参数推导Pucel噪声模型参数的过程,并且给出了微波噪声模型参数的表达式.利用上述方法,针对200 μm栅宽的GaN HEMT器件,提取了噪声模型参数值,并且在ADS仿真软件平台上建立了GaN HEMT器件的Pucel等效电路噪声模型,仿真结果与实测结果在频率为4～18 GHz带宽内吻合较好,说明提出的噪声模型参数提取方法对于GaN HEMT器件噪声仿真的实用性和准确性.     

微波功率管特征参数测试

由于大功率全固态电子设备在体积、性能和可靠性方面的优势,微波功率管将逐步取代行波管在雷达发射机中的核心地位。随着微波功率管的大量应用,正确的测试和评价功率管性能已经显得迫切。微波功率管的特性参数包括直流和射频两部分,直流参数包括:反向击穿电压、反向漏电流和直流增益;射频参数包括:输出功率、增益、顶降、集电极效率、反射系数、1 dB过激励输出功率和抗适配等。文中对微波功率管的特征参数先从理论上阐述,然后结合DC和RF测试平台详细描述了各个特征参数的测试,得出测试结果,并对测试结果进行分析。     

A Method for the Accurate Measurement of the Noise Temperature Ratio of Microwave Mixer Crystals

For the precise measurement of noise temperature ratio of a microwave mixer crystal it is common practice to employ a Roberts coupling network in order to make the Y factor independent of crystal conductance. It is shown here that a number of errors are introduced in this method, the chief of which is failure to consider the effect of transit time loading. It is also shown that the use of cathode lead inductance leads to a much improved measurement of noise temperature ratio.     

微波低噪声放大器机助噪声分析的一种方法

本文提出了微波网络计算机辅助噪声分析的一种方法,推导了所需的等效噪声参数变换公式,这些公式考虑了所有电路元件引入的噪声源.该法可用来解决具有反馈、有耗匹配微波低噪声放大器的噪声分析问题.文中给出了较为详细的噪声分析程序框图.     

Matching Network Design Studies for Microwave Transistor Amplifiers

Several techniques for design of microwave amplifiers using lumped-element and distributed matching networks are discussed. An extension to the Remez-algorithm design approaches is proposed, whereby gain and ripple quantities may be adjusted using a numerical optimization procedure in order to achieve complete absorption of device model elements and also impedance transformation.     

微波晶体管散射矩阵的数值计算

提出了一种计算半导体器件散射矩阵的方法,该方法采用数值分析技术,把描述有源半导体器件的泊松方程和电流连续性方程与描述输入输出匹配网络的电报方程联立求解,得到了晶体管端点电压和端点电流随时间的变化关系,根据电压电流值求出器件的散射矩阵.在设计微波单片集成电路(MMIC)时,可以同时对器件和输入输出匹配电路进行设计,缩短了研制周期.另外计算了SOI MOSFET微波器件的散射矩阵．结果表明,该方法与传统的参数提取方法相比,两者的结果基本一致．     

On the Measurement of Noise Parameters of Microwave Two-Ports (Short Paper)

A novel procedure for determining the noise parameters of microwave two-ports is introduced. In this procedure, the computations necessary to find the noise parameters from the set of measurements of noise temperature (noise figure) are greatly simplified. The assessment of accuracy with which the noise parameters can he determined from a given set of measurement data is straightforward.     

微波晶体管散射矩阵的数值计算

提出了一种计算半导体器件散射矩阵的方法 ,该方法采用数值分析技术 ,把描述有源半导体器件的泊松方程和电流连续性方程与描述输入输出匹配网络的电报方程联立求解 ,得到了晶体管端点电压和端点电流随时间的变化关系 ,根据电压电流值求出器件的散射矩阵 .在设计微波单片集成电路 (MMIC)时 ,可以同时对器件和输入输出匹配电路进行设计 ,缩短了研制周期 .另外计算了 SOI MOSFET微波器件的散射矩阵 .结果表明 ,该方法与传统的参数提取方法相比 ,两者的结果基本一致 .     

网络瓶颈带宽测量的噪声分析

包对/串技术通过两个/多个背靠背发送的测量包所经历的散布间隔来估测一条路径的瓶颈带宽.本文分析了瓶颈带宽测量中的噪声特性,解释了在不同测量包长和测量包数情况下测量样点的分布.基于噪声分析的结论,文中提出了一种基于信号模式的滤波算法(MBFA,Model-Based Filtering Algorithm),它利用信号模式/特征来增强信号、过滤噪声.     

测量噪声背景下微弱正弦信号参数估计的互功率谱方法

本文首次把近代谱估计方法引入到互谱估计中，从理论上证明了互相关函数的Ｙｕｌｅ－Ｗａｌｋｅｒ方程，并在此基础上提出了互谱参数谱估计的矩估计方法和Ｌｅｖｉｎｓｏｎ递推估计方法。该方法可以有效地克服传统的互谱ＦＦＴ算法和互周期图法存在的谱分辩率低，谱估计方差大等缺点。文中还给出了信噪比为－３０ｄＢ的正弦信号参数估计的仿真实例。     

阴极性能参数的一种新的测试方法

本文给出了考虑阴极表面发射不均勾性后，阴极几种参数和发射电流之间的关系式，由此可得到阴极几个性能参数一种测试方法。     

Analysis of Frequency-Conversion Techniques in Measurements of Microwave Transistor Noise Temperatures

Frequency-conversion effects on microwave effective noise temperature measurements are analyzed and conditions under which they are noticeable are given. When necessary, the experimental data can be corrected using the analytical relationships derived here.     

The Calibrating Theory in the Network Parameters Measurement of Microwave and MMW Devices

The paper introduces a special system calibration technology in s-parameters measurement of microwave and millimeter wave devices. The 8-term errors module is built by analyzing the signals flowing in the measurement system. Then the calibration technology using non-standard kits is designed on the base. Finally, the experiment using the calibration technology is introduced.     

微波谐振器无载品质因素的测量方法研究

提出了一种利用微波谐振器散射参数的幅度信息测量无载品质因素的方法.该方法认为在谐振点附近,耦合电路的参数和谐振器的参数相比可以忽略,因此采用简化的等效电路模型,利用谐振点附近的标量散射参数测量值来计算无载品质因素.为了消除散射参数曲线左右不对称所产生的影响,不采用散射曲线上独立的点来计算,而是采用带宽来计算.选取无载品质因素曲线平缓部分进行平均作为测量结果,测量精度接近临界点法.     

The Measurement of Noise in Microwave Transmitters

A tutorial review of the basis for transmitter noise measurements shows that noise is best described and measured as AM and FM noise. The determination of RF spectrum is done by calculation after the AM and FM noise are known. The contribution of AM noise to RF spectrum shape is determined by the power spectral density shape of the AM noise. The contribution of FM noise to RF spectrum is to make the shape that of an RLC circuit resonant response rather than a delta function with a sideband structure. The measurement of AM noise is done with a direct detector diode. The measurement of FM noise for frequencies above 5 GHz is done with a discriminator based on a one-port cavity resonator. The measurement of FM noise below 5 GHz is done with an improved transmission line discriminator which is described in detail. Measurement of low-power low-noise signal sources is made posbible with an injection-locked oscillator for a preamplifier to the discriminator. The most widely used baseband analyzer is the constant bandwidth superhetdrodyne wave or spectrum analyzer. Most differences in measurement results are resolved by understanding the baseband analyzers. At least the baseband spectrum analysis of transmitter noise measurements can be automated with worthwhile savings in time and improvement of documentation.     

Measuring Transistor Large-Signal Noise Figure for Low-Power and Low Phase-Noise Oscillator Design

This paper presents an experimental method for determining additive phase noise of an unmatched transistor in a stable 50-$Omega$ environment. The measured single-sideband phase noise is used to determine the large-signal noise figure of the device. From the Leeson–Cutler formula and a known oscillator circuit with the characterized transistor, the phase noise of the oscillator can be predicted. The method is applied to characterization of several bipolar devices around 3.4 GHz, the frequency of interest for miniature rubidium-based atomic clock voltage-controlled oscillators.