Influence of nonideal LRL or TRL calibration elements on VNA S-parameter measurements

For the 7-term LRL and TRL calibration of a four-sampler vector network analyser (VNA), expressions for the deviations of the measured S-parameters of two-port test objects from their actual values are presented as functions of the deviations of the S-parameters of the LRL/TRL calibration elements from their ideal values. The obtained sensitivity coefficients are suitable for establishing the Type-B uncertainty budget for S-parameter measurements. They show how the measurements are affected by imperfect calibration elements and nonideal connections

Efficient Uncertainty Evaluation of Vector Network Analyser Measurements Using Two-Tier Bayesian Analysis and Monte Carlo Method

Antennas are a key element in any communication system and vector network analyser (VNA) is popular tool for charactering antenna impedance bandwidth. In this paper, an efficient uncertainty evaluation method is proposed for VNA measurement based on its uncertainty propagation mechanism using Bayesian analysis and Monte Carlo method. The proposed method is generic and can be applied to VNA with arbitrary number of ports. In order to obtain the complete information of measurement uncertainty distribution, a two-tier Bayesian analytic process is carried out. The proposed method contains three steps. In the first step, the posterior distribution of each uncertainty source of VNA calibrations is deduced by the use of prior and current sample information through the first-tier Bayesian analysis. In the second step, the obtained posterior distributions of uncertainty sources are taken into the Monte Carlo simulation of one-port VNA measurement uncertainties. In the last step, the results obtained in the second step are used as the prior distribution of the secondary Bayesian evaluation, then the evaluation results of the measurement uncertainty can be obtained with the means, variances and skewness of the probabilistic distribution. The numerical analysis using an antenna measurement results demonstrate the high-efficiency and reliability of this proposed method.Comment: 12th European Conference on Antennas and Propagatio

Improved Evaluation of Planar Calibration Standards Using the TDR Preselection Method

Calibration and correction methods for the Vector Network Analyzer (VNA) are based on the fundamental assumption of the constant error model, which is independent of connected calibration standards and/or devices under test (DUT). Unfortunately, this assumption is not satisfied well for planar calibration standards fabricated by etching technology on soft substrates. An evaluation of the error model is affected especially by variations in the manufacturing process and also by the reproducibility of an assembly. In this paper, we propose error minimization by selecting the best combination of available calibration standards based on time domain reflection (TDR) measurement, which can also be obtained by the fourier transformation from the measured S-parameters. The proposed method was verified experimentally using short, open, load and thru (SOLT) standards fabricated on an FR4 laminate substrate which achieves the essential reduction of the measurement error in the frequency range up to 15 GHz.

Influence of an Extended Stub at Connector Ports on Signal Launches and TRL De-embedding

Characterization of PCBs (Printed Circuit Boards) is usually associated with measurement using a VNA (Vector Network Analyzer) in the frequency-domain or a TDR (Time Domain Reflectometer) in the time-domain. The often used signal launch techniques on PCBs based on the VNA or TDR measurement in the microwave frequency range use SMA or 3.5 mm connectors, in edge-launch or vertical-launch fashions. The signal transition between the launch port and the DUT (Device Under Test) introduces errors in the measurement, which is dominant when compared with a transmission line itself on the PCB as the technologies of PCB manufacturing well developed today. Discontinuities at connector ports depend on the port structures and the dielectric properties of the substrate materials. However, an extended stub at a connector port may significantly influence signal launches, or even corrupt a TRL calibration in a measurement

RF and Microwave Measurements

open1noBasic theory and techniques are concentrated mostly in the first four chapters, where definitions, formulas and references are collected aiming at giving a thorough overview of the most relevant topics: circuit theory, material properties, transmission lines, signal analysis and spectral analysis, including random processes, probability and statistics. The central chapters 5, 6 and 7 deals with three important elements of setups and experiments: cables, printed circuit boards and connectors. The influence on the overall measurement, their modeling and characterization are discussed, keeping an eye on applicable standards. The last four chapters cover advanced aspects of scattering parameters, differential lines and mixed modes, and the use and performance of spectrum analyzer and vector network analyzer.openA. MariscottiMariscotti, A

Physics-based equivalent circuit model extraction for system level PDN and a novel PDN impedance measurement method

“The power distribution network (PDN) plays an important role in the power supply system, especially with the increasing of the working frequency of the integrated circuit (IC). A physics-based circuit modeling methodology is proposed in the first section. The circuit model is extracted by following the current path in the system PDN and the related parameters are calculated based on the cavity model and plane-pair PEEC methods. By extracting the equivalent circuit model, the PDN system will be transformed into RLC element-based circuit. The role of each part of the system will be easily explained and the system behavior could be changed by changing the dominance part accordingly. This methodology makes a good contribution to the system level PDN troubleshooting and layout design optimization. Compared with analytical methodologies, the measurement result is more solid and convincing. The special part of PDN is that the impedance could be as low as several milliohms, and the impedance varies during the frequency, so the accuracy of impedance measurement is challenging. Based on all these requirements, a novel PDN low impedance measurement methodology is proposed, and a probe based on I-V method is designed to support this methodology, which provides a new and practical approach of PDN impedance measurement with easy landing, simple setup, lower frequency, and less instrument quality dependent advantages. This probe could work in a wide frequency range with a relatively sufficient dynamic range”--Abstract, page iii

Bibliography of Lewis Research Center technical publications announced in 1993

This compilation of abstracts describes and indexes the technical reporting that resulted from the scientific and engineering work performed and managed by the Lewis Research Center in 1993. All the publications were announced in the 1993 issues of STAR (Scientific and Technical Aerospace Reports) and/or IAA (International Aerospace Abstracts). Included are research reports, journal articles, conference presentations, patents and patent applications, and theses