提高大反射负载牵引测量准确度研究

针对大反射负载牵引测量过程中,由于矢网系统误差导致的负载牵引测量误差较大问题,提出可行的解决方案。首先,以矢网8项系统误差模型为基础,推导出大反射负载牵引功率增益测量模型。以直通线功率的增益误差和为目标函数,通过优化阻抗点分布、重新构建优化权重函数,实现大反射负载牵引测量准确度的进一步提高。经优化比较,在8 mm频段(负载反射系数模值0.9),系统测量直通线功率增益的最大误差由±1 dB优化到±0.2 dB以内(国内文献报道±0.3 dB),进一步提高在片大反射负载牵引系统测量准确度。此外,通过比较分析,明确反射跟踪误差是影响大反射负载牵引测量准确度的主要系统误差项。     

基于矢量误差修正的实时负载牵引测量模型方法

提出了一种新型基于矢量误差修正的负载牵引测量模型方法。相比于传统负载牵引测量系统,该方法从8-term矢量误差模型入手,建立接收机与被测件端口处电压波的函数关系,通过对矢量网络分析仪进行矢量校准和对内部接收机进行一次绝对功率校准,可实时测量被测件的输入/负载反射系数,输入/输出功率及功率增益、效率等。按照模型方法搭建了相应的硬件系统,与商用Focus的类似系统进行了比较验证,实验结果表明具有良好的效果,证明了所提方法的准确性。     

负载牵引系统校准结果性能评价方法研究

针对采用标准失配衰减网络实现负载牵引测量系统校准时,转换增益测量误差△GT作为校准结果无法直观反映系统测量输出功率(Pout)以及功率附加效率(PAE)的测量性能问题.通过在后端模块的负载端插入经校准的精密极化步进衰减器对△GT进行衰减替代测量,给出了校准结果△GT与Pout及PAE变化量的曲线族,方便设计师快速获取系...     

微波功率固态放大器负载牵引特性的自动测试

提出了一种新的微波功率固态放大器件负载牵引测试方法和校准方法，研制了自动测试系统，并对该测试方法、校准方法和自动测试系统进行了较为详细的讨论。通过实测，获得了微波功率固态放大器输出功率等值线阻抗圆图，验证了所提出的校准方法、测试方法和自动测试系统测试方案是正确的，并具有实用性。     

峰值功率计校准方法的研究

为解决峰值功率计所特有的突发功率参数的校准问题,从在数字移动通信系统中广泛使用的突发信号的各项特殊功率参数以及峰值功率计的测量原理入手,以传统功率校准为基础,结合新参数特点对校准峰值功率计的原理和方法进行了研究,最后建立了校准系统,并给出了突发功率的测量不确定度分析,结果其扩展不确定度为0.17 dB,满足峰值功率计的校准要求。     

一种测量微波功率放大器件输出端反射系数的新方法

本提出了一种测量微功率放大器件输出端反射系数的新方法。通过对可变负载在不同频率和位置下的校准,采用所建立的自动测量系统,运行专门编制的自动控制和数据处理软件,可对微波功率放大器件输出端反射系数进行测量,该方法具有测量简便、迅速、自动化程度高等优点。     

微波功率放大器的性能以及增益的测量

介绍一种微波功率放大器增益的测量方法。经校准件进行TRL校准,校准后分别对所用的两只定向耦合器进行耦合衰减、方向性系数、主线插损和输入口驻波比的频率反应进行测量,同时对终端负载的输入驻波比进行测量。最后由安捷伦矢量网络分析仪组建网络参数测试系统对微波功率放大器的增益进行测量。     

无源光网络中突发光功率计校准方法的研究

介绍了一种利用连续光功率计和示波器进行突发光功率计校准的方法,设计制作了稳定度为±0.01dB/15 min的脉冲光源,通过将脉冲功率的直接测量转换为平均功率的间接测量,实现了突发光功率量值的有效溯源。给出了不确定度评定方法,在0.1 dB分辨力条件下测量不确定度达到0.2dB(k=2)。该方法和装置被广泛用于无源光网络突发光功率计的校准,保证了实际工程中突发光功率测量的准确性。     

宽带在片SOLT校准件研制及表征

针对在片S参数校准,设计制作GaAs衬底SOLT校准组件,通过计算方法对校准组件中直通、开路、短路和负载校准件中偏置传输线的时延和损耗进行定义,运用基于NIST multiline TRL校准的测量方法对校准组件中开路校准件电容和短路校准件电感参数进行提取,结合直流电阻测试法测试负载阻值大小,实现对SOLT校准组件的完整表征。最后用自行研制并表征的SOLT校准组件校准在片S参数测试系统,通过测量无源器件验证校准效果,将测量结果与NIST multiline TRL校准后的测量结果比较,在20 GHz内传输幅度最大偏差0.1 dB,传输相位最大偏差3.5°。     

双程泵浦分立式拉曼放大特性的研究

采用后向泵浦的方案,对新型双程放大分立式光纤拉曼放大器(D-DFRA)的增益特性进行了理论计算,并在双程泵浦放大条件下对增益和噪声特性及受激布里渊散射(SBS)效应进行了实验测量,计算与测量结果较好符合.本文的研究表明:对分立式拉曼放大器通过反射机制实现泵浦光的双程泵浦,可在泵浦功率不变和保持较好噪声特性的同时,大大提升放大器的增益和功率转换效率.增益的提升上限取决于系统受激布里渊散射的阈值,在双程泵浦下增益的上限可得到提高.     

An active millimeter load-pull measurement system using twosix-port reflectometers operating in the W-frequency band

An active load-pull measurement system using two six-port reflectometers operating in the W-frequency band is demonstrated. Ninety loads over the whole Smith chart have been synthesized and measured by both reflectometers. The maximum deviation between both measurement data is 0.02 for the magnitude and 3° for the phase of the reflection coefficient of the 90 loads. The constant power gain circles of a PHEMT operating at 89 GHz are shown and compared with those calculated from its S_ij scattering parameters. The deviation between the radii of circles is less than 0.03     

在片LRRM校准算法研究

研究了LRRM(传输线-反射-反射-匹配负载)校准算法,完善了负载标准测量模型,通过参考面平移将测量结果由被测件中间平移到探针端面,基于MATLAB开发平台编制了校准软件.用研究的校准方法和商用校准方法分别对同一在片散射参数测量系统进行校准,校准后的系统测量相同的短路标准和衰减器.测量结果显示,在100 MHz～110...     

WR-28功率基准系统中等效源反射系数校准研究

在WR-28功率基准系统中,等效源反射系数是确定量热计有效效率、分析不确定度与进行基准功率量值传递的重要参数,其只与接入量热计的定向耦合器有关,而与信号源无关。介绍了传统三端口测试法、直接校准法和最新提出的Shimaoka K法3种三端口器件等效源反射系数的测试方法。在频段26.5~40 GHz,运用Shimaoka K法对三端口器件（定向耦合器）进行等效源反射系数测量,并与其他两种方法实验结果比较,验证了Shimaoka K法的可行性与准确性,同时通过实验比较,由于Shimaoka K法具有的综合优势,使其成为WR-28功率基准中等效源反射系数的最佳测试方法,并以Shimaoka K法为例,对等效源反射系数不确定度进行了评定。     

Measurement and control of current/voltage waveforms of microwavetransistors using a harmonic load-pull system for the optimum design ofhigh efficiency power amplifiers

One of the most important requirements that RF and microwave power amplifiers designed for radiocommunication systems must meet is an optimum power added efficiency (PAE) or an optimal combination of PAE and linearity. A harmonic active load-pull system which allows the control of the first three harmonic frequencies of the signal coming out of the transistor under test is a very useful tool to aid in designing optimized power amplifiers. In this paper, we present an active load-pull system coupled to a vectorial “nonlinear network” analyzer. For the first time, optimized current/voltage waveforms for maximum PAE of microwave field effect transistors (FET's) have been measured. They confirm the theory on high efficiency microwave power amplifiers. The proposed load-pull setup is based on the use of three separated active loops to synthesize load impedances at harmonics. The measurement of absolute complex power waves is performed with a broadband data acquisition unit. A specific phase calibration of the set-up allows the determination of the phase relationships between harmonic components. Therefore, voltage and current waveforms can be extracted. The measurement results of a 600 gate periphery GaAs FET (Thomson Foundry) exhibiting a PAE of 84% at 1.8 GHz are given. Such results were obtained by optimizing the load impedances at the first three harmonic components of the signal coming out of the transistor. Optimum conditions correspond to a class F operation mode of the FET (i.e., square wave output voltage and pulse shaped output current). A comparison between measured and simulated current/voltage waveforms is also presented     

A six-port network analyzer load-pull system for active load tuning

An experimental six-port network analyzer has been used as a load-pull system in an active load tuning configuration. It is shown that by using a dual six-port reflectometer and an appropriate calibration procedure, it is possible to measure at the same reference plane the ratio between the incident and reflected waves and the power flow at the output of the test transistor. Using these two values the simulated load impedance seen by a transistor and the microwave power delivered to the simulated load are calculated. Experimental results on microwave transistor characterization confirm the validity of this method. This technique uses less hardware than conventional methods, and presents a comparable accuracy to conventional techniques     

A Comprehensive Mixed-Mode Time-Domain Load- and Source-Pull Measurement System

We present a novel test set devised for nonlinear balanced device characterization using load-pull techniques. The system is capable of measuring the voltage and current waveforms at the calibration reference planes while independently tuning the device under test (DUT) source and load differential- and common-mode terminations. The test set is designed to address present and future large-signal multiport measurement needs, easing the characterization task while developing new multiport active devices.