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.

Link path design on a block-by-block basis

Abstract: In high-speed data communication systems, the complexity of link path between transmitters and receivers present a challenge for designers to maintain an acceptable bit error rate. An approach is presented in this paper to design the link path on a block-by-block basis. The unique advantage of this approach lies on the physics-based model of each block, which relates performance to geometry and makes design improvement and optimization possible. An example link path involving a backpanel is investigated using the approach. The via stubs and the dielectric materials in the backpanel are demonstrated to be critical factors for link performance in certain situations.

Numerical Investigation of Glass-Weave Effects on High-Speed Interconnects in Printed Circuit Board

Abstract: Numerical method is used to investigate the glass weave effects on via coupling and trace transmission properties. Studies indicate that a simple two-dimensional periodic structure is accurate enough for via coupling simulations while more complicated three-dimensional glass-weave structures have to be used for studies of trace transmission properties. Analytical formulas are provided to estimate the first resonant frequency of the glass weaves. The impact of trace-glass-weave orientations on resonances of traces has been investigated for both single-ended and differential striplines. It has been demonstrated that statistical Gaussian distribution of pitch sizes due to fabrication tolerance and the dielectric losses can reduce the glass-weave effects. The studies here are useful for better understanding of the high-frequency signal integrity performance of printed circuit boards.

A Pattern-Based Analytical Method for Impedance Calculation of the Power Distribution Network in Mobile Platforms

Abstract: A power distribution network (PDN) is essential in electronic systems to provide reliable power for load devices. With faster load transient current and lower voltage tolerance margin for microprocessors in mobile platforms, it is crucial to optimize the printed circuit board (PCB) design to satisfy the strict target impedance. Conventional modeling methods become impractical in mobile platforms due to the characteristics of high-density interconnect PCB and limited layout space. To overcome these issues, a pattern-based analytical method for the PDN impedance calculation is presented in this article. Based on the localized patterns formulated by the relative relationships between the adjacent vias, parasitic elements are analytically determined for different regions of the entire PCB structure. With the assistance of this method, a practical modeling methodology is developed to construct an equivalent circuit with one-to-one correspondence to the PCB's physical geometry. As a result, the PDN design can be efficiently optimized, especially in the predesign stage, to accelerate the development process. Finally, the proposed method is validated by measurements and full-wave simulations using a real mobile phone PCB in production.

Common-mode current harmonics on differential pair cable shields operating in a regime as high as 2.125 Gb/s

Abstract: The spectral harmonics of common-mode currents induced on high-speed differential cables operating at 1.0625 and 2.125 Gb/s were investigated using an analytical model and an experiment. Modeling of a differential clock type signal using waveforms with exponential rise and fall and adjustable delay skew and duty cycle allowed prediction of the spectral content of the resulting common-mode voltage waveform. A shielded test board was constructed to allow generation of a differential signal with selectable amounts of delay skew. Using an IC driver on the board as a differential source, common-mode current was measured at the source end of a long cable that was at the far end for both the differential and the common-modes. Modeled and measured results show that the fundamental frequency of the clock type waveform and the higher harmonics increase with increasing delay skew.

Eliminating non-linear RSS reporting error in a radiated RSS-based TIS testing method

Abstract: A fast total isotropic sensitivity (TIS) testing method based on radiated sensitivity measurement and received signal strength (RSS) reporting is studied in this paper. An innovative method for eliminating a non-linear system error in RSS reporting is presented and incorporated into the testing procedures. Compared to the methods specified in the Cellular Telecommunications and Internet Association (CTIA) test plan, the improved fast TIS testing method can considerably reduce measurement uncertainty while maintaining the fast testing speed. Thus, it is very suitable for receiver sensitivity testing of single input single output radio systems having RSS reporting, such as cellular communication, WiFi, and bluetooth systems.

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.