Jun Fan

Bio: Jun Fan is an academic researcher from Missouri University of Science and Technology. The author has contributed to research in topics: Equivalent circuit & Printed circuit board. The author has an hindex of 36, co-authored 482 publications receiving 5641 citations. Previous affiliations of Jun Fan include Ulsan National Institute of Science and Technology & University of Missouri.

Investigation of S21 magnitude extraction methodologies by using a pattern generator and sampling oscilloscope

Abstract: S-parameter measurements of a digital link path are measured with VNAs or high-end TDRs. For multi-port in-situ measurements, these become inconvenient and time consuming. However, it can be handled more conveniently in the time domain (TD) by using a pattern generator and a multichannel sampling oscilloscope, which are used for eye-diagram measurements. This paper outlines and compares three methods to extract S 21 magnitude from the time domain measurements using a pattern generator and a sampling oscilloscope for any channel. The setup differs in terms of the input waveform and the processing. The comparison provides insight into the advantages and limitations of each method.

Radiation compatible ports and loads for the PEEC method

Abstract: The partial element equivalent circuit method (PEEC) has been popularly used for signal integrity and power integrity. Its port setup usually only includes conductive effects in the format of current sources or voltage sources. However, its radiation effect was neither included nor studied. In this paper, for the first time we provide novel solutions to approximate the radiation contributions from the port and load setups of PEEC. They serve to compensate the accuracy of electromagnetic radiation analysis based on PEEC approach. The proposed radiation compatible ports and loads can be easily applicable to EMI related analysis.

S-parameters quality estimation in physical units

Abstract: S-Parameters are the most common way to describe electrical behavior of linear electric networks. However, any available S-Parameters that is available for describing a physical system is not perfectly accurate and does not describe it comprehensively. It becomes important to be able to estimate the quality of existing data in order to achieve reliability of the results and conclusions developed based on it. A metric is created in the present work to estimate a physical system based on passivity, reciprocity and causality properties in physical units. First, based on the original S-Parameters, will be created passive, causal and reciprocal S-Parameters; then similarity metric will be defined in time domain to get estimation in physical units; finally similarity metric in time domain will be applied between original and passive, causal and reciprocal matrices to get correspondingly passivity, causality and reciprocity estimations in physical units.

Uncertainty Reduction of Fracture Permeability Based on a Comprehensive Bayesian Framework

Abstract: Summary Natural fracture brings challenges in history matching of basement rock hydrocarbon reservoir. One of the challenges is the uncertainties remaining in the modelling and simulation processes. How to quantify and reduce the uncertainties related to fractures is important not only for the efficient development of the hydrocarbon reservoirs, but also important for controlling the risk of the decision-making. This study proposes a comprehensive Bayesian framework to quantify the uncertainty and reduce the uncertainty remaining in the flow models for naturally fractured reservoirs. The proposed framework is based on Bayesian theory, with combining Distance-based Generalized Sensitivity (DGSA) and Approximating Bayesian Computation. Sensitivity analysis is used to evaluate the sensitivity of the model parameters. Approximating Bayesian Computation is a likelihood-free method to estimate the posterior. In addition, Embedded Discrete Fracture Method is employed to simulate the fluid flow behavior in fracture media. The proposed method is used in a naturally fractured basement rock reservoir. The results reveal that the method can efficiently reduce the uncertainty related to the fracture flow properties.

Averaged Behavior Model of Current-Mode Buck Converters for Transient Power Noise Analysis

Abstract: Accurate evaluation and simulation of power noise is critical in the development of modern electronic devices. However, the widely used target impedance fails to predict the low-frequency noise generated in a device due to the existence of the dc–dc converter, whose output impedance can change under different loading conditions. A physical circuit model is then desired to replicate the behavior of a voltage regulator module, and the average technique is an efficient method to estimate the noise of a pulsewidth-modulated (PWM) converter. With the emergence of converters with adaptive on-time (AOT) controllers, more complex averaging methods are required, but none of them supports transient simulation. A general, efficient, and accurate modeling technique is presented in this article, whose framework supports both current-mode PWM and AOT controllers. In addition, a novel two-step parameter extraction method is proposed, which can be used to evaluate the equivalent values of internal feedback parameters of an encrypted simulation model or from measurement. The modeling method is validated by both simulation and measurement.

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

IEEE Transactions on Microwave Theory and Techniques and Antennas and Propagation Announce a Joint Special Issue on Ultra-Wideband (UWB) Technology

Abstract: Before the emergence of ultra-wideband (UWB) radios, widely used wireless communications were based on sinusoidal carriers, and impulse technologies were employed only in specific applications (e.g. radar). In 2002, the Federal Communication Commission (FCC) allowed unlicensed operation between 3.1–10.6 GHz for UWB communication, using a wideband signal format with a low EIRP level (−41.3dBm/MHz). UWB communication systems then emerged as an alternative to narrowband systems and significant effort in this area has been invested at the regulatory, commercial, and research levels.