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.

Application of dipole-moment model in EMI estimation

Abstract: This paper used magnetic near fields to extract the dipole-moment model to represent the real radiation source. This method prevents the measurement of electric fields so that the scanning time and points are saved significantly. These equivalent dipole-moment models can take the place of the real radiation source in the full-wave simulation tool. The electromagnetic interference between the real source and victim structures are well predicted in the simulation by the dipole-moment model. This is validated by a numerical example in this paper.

Power integrity investigation of BGA footprints by means of the segmentation method

Abstract: The engineering of the power delivery network is becoming a fundamental issue in the design of high speed digital systems on PCB's. In fact, providing the required power to the different IC's at the specified noise-free voltage levels allows a correct functioning of the overall PCB systems. More over, the ongoing trend of replacing active devices with peripherally located I/O and PWR/GND pins with areally located I/O and PWR/GND pins (BGA packaged) increases the complexity of the models, when power delivery issues need to be studied in a larger contest, such as the overall PCB's. The employment of the powerful, but simple, concept of the segmentation method allows investigation of the power delivery network of the PCB systems in two fundamental stages. During the first stage, a small cut out of the board corresponding to the BGA footprint is modelled with a 3D full wave simulation tool. During the second stage the equivalent impedance network representation corresponding to this cut out is combined, by means of the segmentation method, with larger pieces of a board, whose network representations can be extracted from the closed form expression of the cavity model approach

An Extended Cavity Method to Analyze Slot Coupling Between Printed Circuit Board Cavities

Abstract: In high-speed multilayer printed circuit boards, gaps are commonly used in planes, where different areas are utilized for different logic levels or where noise isolation from one area to another is necessary. However, these gap structures could present serious signal integrity and electromagnetic interference issues. In this paper, an extended cavity method is developed to characterize noise coupling caused by slots or gaps in the middle plane of a three-plane structure. According to the equivalence principle, the entire structure can be divided into two plane pairs without any slot in the middle plane, and then, equivalent magnetic currents are needed in both plane pairs in the slot region to retain the same field distributions. Dyadic Green's functions of a rectangular cavity with perfect electric conductor top and bottom surfaces and perfect magnetic conductor sidewalls are derived for both electric and magnetic current excitations. Magnetic auxiliary ports with “magnetic voltage” and “magnetic current” are defined in the slot region to enable vertical connections of two plane pair. The conventional cavity model and segmentation technique are extended in this paper to handle such magnetic auxiliary ports. The proposed method can be used to effectively analyze the apertures with arbitrary shapes and is validated by full-wave simulations.

A Novel System-Level Power Integrity Transient Analysis Methodology using Simplified CPM Model, Physics-based Equivalent Circuit PDN Model and Small Signal VRM Model

Abstract: The goal of a well-designed power delivery network (PDN) is to deliver desired voltage level from the source to destination, in other words, to minimize voltage noise and errors delivered to chip. This paper provides power integrity engineers a guideline to model PDN agilely in a simplified method and choose specific voltage regulator module model under specific circumstances. These comparisons and studies present the advantage of this novel methodology using equivalent circuit model for system level power integrity transient analysis.

Measurement validation for radio-frequency interference estimation by reciprocity theorem

Abstract: This paper presents the measurement validation of reciprocity theorem method for near-field coupling estimation. The overall problem is decomposed into two parts, the first part is called forward problem, and the second part is called the reverse problem. For forward problem, the noise source IC is modelled by physics-based dipole moment model with data obtained from a near-field scanning plane, then the tangential E and H fields on a Huygens's box enclosing the victim antenna are calculated by analytical expression. In reverse problem, the victim RF antenna is modelled in full-wave simulation tool and the tangential E and H field are obtained by simulation. With tangential E and H field obtained in forward problem and reverse problem, the coupled noise power is then estimated by reciprocity theorem. The estimated noise coupling power is compared with measured power at the victim antenna port with IC excited. The difference is within 5dB which is acceptable for engineering practice.

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.