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 …

I and i

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

Introduction to Electromagnetic Compatibility

Antenna Theory And Design

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.

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

Simulating the dynamic characteristics of a PN junction at the microscopic level requires solving the Poisson's equation at every time step. Solving at every time step is a necessary but time-consuming process when using the traditional finite difference (FDM) approach. Deep learning is a powerful technique to fit complex functions. In this work, deep learning is utilized to accelerate solving Poisson's equation in a PN junction. The role of the boundary condition is emphasized in the loss function to ensure a better fitting. The resulting I-V curve for the PN junction, using the deep learning solver presented in this work, shows a perfect match to the I-V curve obtained using the finite difference method, with the advantage of being 10 times faster at every time step.

Solving Poisson's Equation using Deep Learning in Particle Simulation of PN Junction

Far-end crosstalk (FEXT) noise is one of the major issues that limits signal integrity performance for high-speed digital products. It is important to estimate the crosstalk noise accurately to avoid noise margin failure or overdesigned transmission lines. Traditionally, analytical formulas for crosstalk noise are based on lossless and perfect impedance match assumptions, which provide limited guidance for a practical high-speed transmission line design. A phenomenon is observed that a lossy conductor increases the FEXT on coupled striplines. To provide a reasonable explanation, analytical and numerical investigations were performed using a modal analysis based approach. A new FEXT component due to the lossy conductor is proposed. Such FEXT component is important to a high-speed stripline design because it is a major contributor when all terminals are matched. To estimate the impact of loss on FEXT, a practical and fast estimation approach is proposed.

Comprehensive and Practical Way to Look at Far-End Crosstalk for Transmission Lines With Lossy Conductor and Dielectric

Noise coupled from switched-mode power supply to signal nets can cause severe signal integrity problems because of the existence of fast switching voltages and currents in the circuit. In this paper, noise coupling mechanism from a synchronous buck converter to a nearby signal trace is studied using a hybrid non-linear model, which combines the synchronous buck converter circuit model and the passive electromagnetic model of the PCB coupling. General design guidelines to mitigate the noise coupling in practical printed circuit board (PCB) designs are provided based on the modeling results.

Investigation of noise coupling from switching power supply to signal nets

The mechanism of the passive intermodulation (PIM) distortion caused by the loose contact in coaxial connectors is of great importance in wireless communication systems. This paper focuses on the effect of the additional impedance on PIM levels in coaxial connectors. First, the additional impedance and PIM levels of the loose contact coaxial connectors are measured. Then, the S-parameters and the additional impedance with three different loose contact cases are simulated. Finally, a modified coaxial connector with different values of conductive tapes is designed to verify the additional impedance impacts on the PIM level. It is shown that the increase of the additional impedance of the metal–metal loose contact will lead to the deterioration of PIM levels in the coaxial connector.

Jun Fan

Papers

Solving Poisson's Equation using Deep Learning in Particle Simulation of PN Junction

Comprehensive and Practical Way to Look at Far-End Crosstalk for Transmission Lines With Lossy Conductor and Dielectric

Investigation of noise coupling from switching power supply to signal nets

Measurement and Analysis of Passive Intermodulation Induced by Additional Impedance in Loose Contact Coaxial Connector

New De-Embedding Techniques for PCB Transmission-Line Characterization