Electromagnetic radiation from multilayer printed circuit boards: a 3D FDTD-based virtual emission predictor

A novel FDTD-based virtual electromagnetic compatibility tool for the prediction of electromagnetic emissions from a multilayer printed circuit board is introduced. Tests are performed with characteristic structures and sample simulation results are presented

Radar cross-section (RCS) analysis of high frequency surface wave radar targets

Realistic high frequency surface wave radar (HFSWR) targets are investigated numerically in terms of electromagnetic wave - target interactions. Radar cross sections (RCS) of these targets are simulated via both the finite-difference time-domain (FDTD) method and the Method of Moments (MoM). The virtual RCS prediction tool that was introduced in previous work is used for these investigations. The virtual tool automatically creates the discrete FDTD model of the target under investigation and performs the FDTD RCS analysis. It also automatically constructs a MoM wire grid model of the target; therefore, it is also possible to compare FDTD results against the MoM-based NEC (Numerical Electromagnetic Code) data. Bi-static RCS patterns under a variety of illuminations over the whole HF band (3-30 MHz) are presented. The mono-static RCS vs. frequency of these targets is also given

The frequency of Duchenne muscular dystrophy/Becker muscular dystrophy and Pompe disease in children with isolated transaminase elevation: results from the observational VICTORIA study

IntroductionElevated transaminases and/or creatine phosphokinase can indicate underlying muscle disease. Therefore, this study aims to determine the frequency of Duchenne muscular dystrophy/Becker muscular dystrophy (DMD/BMD) in male children and Pompe disease (PD) in male and female children with isolated hypertransaminasemia.MethodsThis multi-center, prospective study enrolled patients aged 3–216 months with serum alanine transaminase (ALT) and/or aspartate transaminase (AST) levels >2× the upper limit of normal (ULN) for ≥3 months. Patients with a known history of liver or muscle disease or physical examination findings suggestive of liver disease were excluded. Patients were screened for creatinine phosphokinase (CPK) levels, and molecular genetic tests for DMD/BMD in male patients and enzyme analysis for PD in male and female patients with elevated CPK levels were performed. Genetic analyses confirmed PD. Demographic, clinical, and laboratory characteristics of the patients were analyzed.ResultsOverall, 589 patients [66.8% male, mean age of 63.4 months (standard deviation: 60.5)] were included. In total, 251 patients (188 male and 63 female) had CPK levels above the ULN. Of the patients assessed, 47% (85/182) of male patients were diagnosed with DMD/BMD and 1% (3/228) of male and female patients were diagnosed with PD. The median ALT, AST, and CPK levels were statistically significantly higher, and the questioned neurological symptoms and previously unnoticed examination findings were more common in DMD/BMD patients than those without DMD/BMD or PD (p < 0.001).DiscussionQuestioning neurological symptoms, conducting a complete physical examination, and testing for CPK levels in patients with isolated hypertransaminasemia will prevent costly and time-consuming investigations for liver diseases and will lead to the diagnosis of occult neuromuscular diseases. Trial RegistrationClinicaltrials.gov NCT04120168

Radar cross section (RCS) modeling and simulation, part 2: a novel FDTD - based RCS prediction virtual tool for the resonance regime

A novel FDTD-based virtual radar cross section (RCS) prediction tool is introduced. Characteristic examples using simple three-dimensional structures, as well as more-realistic complex air and surface targets, are presented. The virtual tool automatically constructs a wire-grid model of the structure under investigation. It is therefore also possible to compare FDTD results against MoM-based NEC (Numerical Electromagnetics Code) data. It is shown that this virtual tool can be used for both educational and research purposes

A two-dimensional FDTD - based virtual visualization tool for metamaterial - wave interaction

Metamaterials (MTM) have become a major electromagnetic research topic. Initial studies have focused on understanding their electromagnetic properties and interactions. This paper presents a novel virtual tool, MTM-FDTD, for the visualization of electromagnetic wave interacting with different metamaterials. Snapshots from characteristic examples during these interactions are presented. Scenarios with normal and oblique incidences, demonstrating focusing beams in planar metamaterials and the existence of negative refractive angle, respectively, are presented. One beauty of this virtual tool is that video clips of wave-metamaterial interactions may easily be produced.IEEE Antennas and Propagation Societ

A multipurpose FDTD-based two-dimensional electromagnetic virtual tool

A novel, multipurpose, FDTD-based two-dimensional electromagnetic virtual tool has been designed and introduced. A variety of electromagnetic problems, including radio wave indoor/outdoor, urban/rural propagation, electromagnetic compatibility, resonators, closed/open periodic structures, and linear and planar arrays of radiators can be simulated. This paper describes the software and its use in electromagnetics courses

Antenna calibration for EMC tests and measurements

An antenna is calibrated in an open-field test site (OFTS) and/or an anechoic chamber, which facilities themselves need calibration. The procedures for calibrated test sites (CALTS) are given in the CISPR and ANSI/IEEE standards. The characteristic parameter for calibrated test sites is the normalized site attenuation (NSA). Theoretical calculations and practical measurements of normalized site attenuation are first presented. Antenna-factor (AF) and/or absolute-gain measurement methods are then reviewed. Finally, an alternative antenna calibration approach is given in this tutorial.IEEE Antennas and Propagation Societ

A novel virtual FDTD-based microstrip circuit design and analysis tool

A novel FDTD-based virtual education/research tool is introduced, and characteristic examples are presented. The beauty of this tool comes from its visualization power, as well as easy-to-use design steps. The tool can be used effectively in microstrip circuit analysis and design problems

Validation, verification and calibration in numerical electromagnetics : Canonical tests and comparisons

Sevgi, Levent (Dogus Author)Modeling and numerical simulation in electromagnetics is discussed in this paper with emphasize placed on validation, verification and calibration. Canonical examples from antennas, propagation to microstrip circuits are presented. Tests against measurements, when available, are also presented.IEEE,IEEE Electromagnetic Compatibility Society,International Union of Radio Science, URSI,Research-and-production Enterprise "Proryv