表面贴装器件S参数测量方法研究

表面贴装器件(SMD)的应用越来越广泛,它已逐渐取代了传统的同轴接口器件,测量表面贴装器件的S参数就成了需要重点解决的问题。矢量网络分析仪是测试器件S参数的首选仪器,但现如今所有的矢量网络分析仪都是同轴式的仪器,如何利用同轴式矢量网络分析仪测量表面贴装器件的S参数就成了矢量网络分析仪研究的重点方向之一,测量表面贴装器件的S参数必须把器件放在测试夹具中,而传统的同轴式矢量网络分析仪的校准参考平面和测试夹具的测量平面不一致,这样测试的S参数就包含了器件和测试夹具两部分的S参数,为了精确测试器件的S参数,必须消除测试夹具所带来误差,端口延伸和TRL校准是补偿校准参考平面和仪器的测量平面不一致而引起的误差的最简单方法之一。本文主要介绍了使用矢量网络分析仪测量表面贴装器件(SMD)S参数的两种方法即端口延伸法和TRL校准法,实际应用结果表明,这两种方法合理有效,易于掌握。     

在片高低温S参数TRL校准件的研制

为了经济有效地提高在片高低温S参数试验系统的准确度,设计制作了在片高低温TRL校准件.首先,总结了目前常用的3种在片高低温S参数校准方法的具体做法和不足;其次,介绍了TRL校准件的设计和定义的方法;然后,阐述了校准件的使用方法;最后,通过相关试验,对该校准件的校准效果进行了验证,结果表明,该方法的测量效果较为理想,具有一定的推广使用价值.     

RF-LDMOS射频功率器件内匹配电路设计

介绍了一种RF-LDMOS功率器件内匹配电路的设计方法.首先通过ADS/De-Embed提取管芯的S参数,得到其输入阻抗;然后建立LC内匹配电路,确定电容值、电感值以及提升的目标阻抗值;最后在HFSS中建立金丝键合线模型,确定金丝键合线的长度及根数,完成内匹配电路的设计.该内匹配电路设计的目的是将管芯的输入阻抗提升为较大的阻值,使得在PCB上进行外匹配设计更为方便.设计仿真结果表明,通过在管壳内加入合适的内匹配电路,在目标频率1.2GHz时,将管芯的输入阻抗从0.8 Ω提升到12.4Ω,S11小于-46 dB,符合设计要求.为LDMOS功率器件设计者提供了一种有效的内匹配设计方法.     

非理想校准件对S参数测量结果的影响

TRL校准方法是矢量网络分析仪（Vector Network Analyzer,VNA）校准的常用方法之一,它通过对直通件、反射件和传输线3个标准件的测量,经过一系列计算获取各误差项的值。但是在实际测量中,这些校准件并不能在整个频带范围内具有理想的特性,从而在实际测量时会引起被测件S参数的测量不确定度。对于使用日益广泛的多端口VNA而言,测量不确定度的分析比二端口VNA更为复杂,目前对其开展的研究还不够广泛深入。文章以四端口VNA为例,对TRL校准过程中由非理想标准件引起的被测件的S参数测量不确定度进行研究。首先,运用广义节点的思想将四端口VNA的S参数测量不确定度用矩阵形式表示,再运用广义TRL校准方法,求得各误差项及其偏移的值,最终求得灵敏度系数的解析式,它可以对四端口VNA进行S参数测量不确定度的B类评估。     

测量平衡器件混合模S参数的数学巴伦法

由于传统网络分析仪各测量端口都是单端的,无法通过直接测量得到平衡器件混合模散射参数(S参数).数学巴伦法是一种数学上的处理方法,在实际测量时将每个差分端口的两端分别与地看作一个单端(非平衡)端口,用普通网络分析仪测量出多端口非平衡S参数,再经过数学处理得到平衡器件的混合模S参数,而不需外加物理巴伦.文章给出了数学巴伦法的基本理论,推导了混合模S参数与实测非平衡多端口S参数之间的关系,以一个双定向耦合器作为例验证了理论的正确性,所得混合模S参数处理结果与直接测量结果吻合很好.     

0.1 - 110 GHz在片去嵌技术

研究了0.1 - 110 GHz S参数在片去嵌技术,给出了输入、输出端口非对称下的直通-反射-传输线（TRL）和传输线-反射-匹配（LRM）的去嵌算法求解结果。在 InP衬底上设计了TRL和LRM去嵌标准件,采用两种无源元件验证了去嵌结果的正确性,并且对TRL和LRM在0.1-110 GHz范围内的去嵌准确性进行对比。通过在0.1 - 40 GHz运用 LRM方法,和在75 - 110 GHz运用TRL方法,获得了有源器件HBT两频带内的本征S参数,并对去嵌前和去嵌后提取的小信号电流增益及单向功率增益进行对比。通过插值,可得出待测件0.1 - 110 GHz完整的S参数。     

管芯S参数的提取技术

介绍了一种新颖的提取管芯S参数的方法。这种方法从电路等效理论出发,把除管芯以外的寄生参数用等效电路表示,用微波仿真软件去除这部分电路的影响,就可得出管芯的S参数。本文使用的微波仿真软件是Microwave Office。此方法简单易行、精确度高,有很好的实用价值。     

一种用于氮化镓晶体管建模的TRL校准方法

直通-反射-延迟线(TRL)校准相对于短路-开路-负载-直通(SOLT)校准是一种更加准确且易于实现的校准方法,尤其适用于二端口及多端口的非同轴测量。文中针对Wolfspeed公司的氮化镓晶体管CGH40010F的S参数测量问题,分析讨论了TRL校准在网络分析仪中的误差盒模型,在此基础上设计制作了一套TRL校准件,其工作频率范围为1～6 GHz,在此频段内直通和延迟线均达到S_ii(i=1,2)幅值小于-15 dB,S_ij(i,j=1,2;i≠j)幅值大于-0.8 dB;将该校准件特性指标内置到矢量网络分析仪中进行校准测试,实测结果表明,经过TRL校准后的氮化镓晶体管小信号S参数与官方数据手册中一致,验证了该校准测量方法及据此设计制作的TRL校准件是有效的。     

热敏电阻在发光二极管热阻测量中的应用

文章介绍了用热敏电阻测量发光二极管热阻的实验装置和原理.把微小尺寸热敏电阻封装在发光二极管管芯支架上,用一次指数衰减函数拟合封装在发光二极管管芯支架上的热敏电阻R-T阻温曲线.通过测量微小尺寸热敏电阻电阻,计算发光二极管管芯温度以及发光二极管的热阻.该实验方法原理简单、明了,数据处理方便,结果可信.     

基于TRL的3mm波段变容二极管对建模方法

本文在商用变容二极管的简化电路模型基础上,对非线性肖特基结和周围的无源结构进行了基于石英介质的TRL去嵌入建模分析,在考虑二极管无源区和封装环境各种寄生参量情况下,建立了精确的3mm波段二极管对电路模型.采用TRL算法,通过拟合初始二极管S参数曲线和TRL测试参数确定芯片电路模型中各集总参数元件数值.二极管对在片各项测试结果和基于改进的电路模型仿真结果相吻合.该二极管对电路模型建模方法可应用于毫米波亚毫米波混频倍频电路的准确分析与设计.     

A Simplified Calibration Methodology for On-Chip Couplers

In this paper, we propose a simplified calibration methodology for on-chip couplers to de-embed the unwanted but unavoidable parasitics introduced by the probing pads as well as the effects originating from redundant feeding lines. The traditional TRL (Thru, Reflect, Line) calibration technique for single-ended two-port device is extended and applied to symmetrical 4-port devices that can be decomposed as the odd- and even-mode equivalent circuits. Accordingly, the TRL calibration standards in the balanced format are designed as well. As a final step, single-ended 4-port S-parameters of device under test (DUT) are reconstructed through its de-embedded odd- and even-mode 2-port S-parameters. To validate the efficacy of our proposed calibration methodology in extracting S-parameters of DUT, models in HFSS, such as a branch-line coupler and a coupled-line coupler with probing pads, and balanced TRL calibration standards are generated. After performing the de-embedding procedures proposed in this paper, the extracted S-parameters agree well with the simulated S-parameters of DUT without adding any pads and feeding lines for measurement.     

Systematic uncertainties of the complex antenna factor of a dipole antenna as determined by two methods

The complex antenna factor (CAF) of a dipole antenna with a balun can be determined from the effective length and the input impedance of the antenna element and the S-parameters of the balun. The effective length and the input impedance are calculated by a numerical method such as the method of moments. The S-parameters are measured using a network analyzer with its thru-, reflect-, and line-conditions (TRL) calibration. Alternatively, the CAF can be determined by a modified three-antenna method on a ground plane. In the present paper, the systematic uncertainties of the two methods are estimated in the frequency range of 30-1000 MHz in order to clarify the potential for application of the two methods and to determine areas for improvement. The CAF values determined by these two methods are compared, and the results of this comparison indicate the validity of the uncertainty estimations. In the measured balun method, the TRL measurement should be improved in the low-frequency range (30-100 MHz), and in the three-antenna method, the antenna positioning should be improved.     

Modulated S-parameter measurements for isothermal microwave devicecharacterization

The validity of extracted microwave device models is critically dependent on the completeness, accuracy, and appropriateness of the starting device characterization data. In this letter we will present a novel technique for determining the S-parameters of a device under isothermal (i.e., no heating) operation. Additionally, this technique can be applied to determining the CW S-parameters under more extreme (e.g., forward bias/breakdown) operation. By pulse-biasing the device from the “OFF” to the “ON” state, while performing standard S-parameter measurements, resultant data is found to be characteristic of the weighted (by duty factor) scalar sum of the devices “ON”-state and “OFF”-state S-parameter(s). We will show how these measurements can then be used to interpret the devices isothermal CW S-parameters     

C波段单片有源环行器

报道了一种源耦合反馈单片有源环行器的研究结果、该单片电路采用实测ＦＥＴ的Ｓ参数进行微波ＣＡＤ优化设计，内部包含有３个３００μｍ栅宽的ＦＥＴ，芯片面积１．７ｍｍ×１．９ｍｍ。采用ＧａＡｓ的离子注入平面工艺，芯片电路具有良好的均匀性、一致性。在３．５～４．５ＧＨｚ内，电路插入损耗约７．５ｄＢ，隔离度为２１～２６ｄＢ，驻波比基本小于２。     

Methodology for Small-Signal Model Extraction of AlGaN HEMTs

Both large- and small-periphery AlGaN high- electron mobility transistors (HEMTs) will find applications in microwave systems from 2 to 40 GHz because of their superior power handling capability. A self-consistent approach is presented for the linear model's parameter extraction from measured S-parameters. The model for parasitics is selected to reflect loading from both the probe pads and the interconnect regions, including the air bridges. The objective is to accurately extract intrinsic model parameters as the device periphery is increased from 50 mum to 1 mm and to isolate the effects of device layouts, including air bridging the source regions. To accurately extract the shunt and series parasitics, the device must be represented in its ON- and OFF-states determined by the gate and drain bias. The intrinsic device capacitances are not negligible in the forward and beyond-pinchoff reverse bias states at zero drain bias and must be accounted for. With these corrections to the measured S-parameters, consistent results for the intrinsic device parameters are obtained with both small- and large-periphery AlGaN HEMTs.     

用于太赫兹InP基PHEMTs 1~110GHz全频段在片测试的系统校准方法的对比研究

本文分别采用Multiline-TRL (Thru-Reflect-Line)和LRM (Line-Reflect-Match) 在片系统校准方法,与传统的SOLT (Short-Open-Load-Thru) 校准方法在InP基PHEMTs片上S参数测试方面进行定量的对比。首次在70 KHz~110 GHz全频段实现一次校准,减小了传统的分段测试多次校准带来的系统误差,校准更加方便简单。对比结果表明,基于Multiline-TRL校准和LRM校准后测量的S参数一致,且均优于传统的SOLT校准方法,尤其是在高频段结果更加准确。首次基于拐点进行外推,且器件展现了优良的射频特性,包括最大电流增益截止频率ft= 247 GHz,最大振荡频率fmax= 392 GHz,其准确度高于传统的基于无拐点进行的外推。首次基于LRM校准测得器件的1~110 GHz全频段S参数,建立了器件的1~110 GHz全频段小信号模型,而非基于传统的通过低频测试数据外推获得。     

射频场效应晶体管的交流小信号建模技术研究

提出了新的金属-氧化层-半导体-场效晶体管（MOSFET）器件的小信号等效电路结构,提取了等效电路结构的元件参数值,在器件建模型软件IC-CAP2008下,对等效电路模型和提取的元件参数进行编译,生成了能够应用于射频与微波领域的场效应晶体管的高频小信号器件模型,将生成的器件模型编译到高频仿真软件ADS中,并调用S参数仿真器对器件模型进行S参数仿真,最后对比了仿真结果与测试数据的差异性,对生成的器件模型做出了误差分析,展示了所建小信号模型的良好性能。     

Pure-mode network analyzer for on-wafer measurements of mixed-modeS-parameters of differential circuits

A practical measurement system is introduced for measurement of combined differential and common-mode (mixed-mode) scattering parameters, and its operation is discussed. A pure-mode system measures network parameters of a differential circuit in the fundamental modes of operation, and has improved accuracy over a traditional network analyzer for the measurement of such circuits. The system is suitable for on-wafer measurements of differential circuits. The transformation between standard S-parameters and mixed-mode S-parameters is developed. Example microwave differential structures are measured with the pure-mode vector-network analyzer (PMVNA), and the corrected data is presented. These structures are simulated, and the simulated mixed-mode S-parameters correlate well with the measured data