Held J.,Siemens AG |
DesignCon 2015 | Year: 2015
To achieve high accuracy even in the mΩ- And GHz-region for measurement of power supply impedances in printed circuit boards, in most cases the 2-port VNA measurement is the tool of choice. Due to space and cost constraints, the use of soldered SMA-connectors for the measurement from both sides of the PCB is not applicable. If the impedance shall be measured in the area below an IC, where no connector with pins for through-holes can be used, the measurement is only possible from the opposite side of the PCB, i.e. from only one side. In this paper a more practical approach is presented, which requires only a fraction of space of an SMA-connector (8 square millimeters instead of 50) and only one side of the PCB for probing. Small contact pads with short traces and vias down to the inner power- And ground-planes are used. These contact pads are contacted by relatively inexpensive and robust wafer-probers, having only one signal- And one ground-pin with a contact distance of 500μm. To evaluate the performance of this approach, a 3D-field-simulation with CST MWS is used. Several cases are considered: SMA-connectors, GSG-probes, SG/GS-probes, measurement from one side of the PCB and the influence of the deembedding of the via-trace-pad-unit on the results.
Microwave Journal | Year: 2011
The use of 3D EM simulation with CST Microwave Studio for solving a GSM immunity issue is shown. A device is simulated with 3D simulation software and the CAD model is imported and the material properties of the different parts are adjusted for 3D field calculation. A strong resonance at 917 MHz is observed for all three geometrical E-field components x, y and z. The capacitance between the crimp pad and PCB GND is found to reduce the impedance between the housing and PCB GND around 900 MHz and reduces the quality of the cavity. The basic idea of soldering the amplifier holder to the PCB GND system by means of a 5 pF capacitor is verified by a series of simulations. The contact of housing-GND to PCBGND has an impact on the cavity resonance quality and frequency and the capacitors placed in the resonance cavity pick up the disturber and feed it to the amplifier.
IET Seminar Digest | Year: 2013
Lightning simulations with CST STUDIO SUITE® Direct time-domain analysis enables lightning standards to be simulated and peak voltages, currents and dwell times predicted Approach for modelling composite material simulation: Detailed filament/weave level analysis using unit cell models TLM thin panel and seam models provide efficient techniques for modelling diffusion and joint resistance CST CABLE STUDIO extends the cable modelling to highly complex and realistic cable bundles Direct and near strike simulation at the full vehicle level is possible in reasonable computer memory and run times.
2013 IEEE International Conference on Signal Processing, Computing and Control, ISPCC 2013 | Year: 2013
Remote sensing techniques are widely used for land cover classification and related analyses; however the availability of high resolution images have limited the accuracy of pixel based approaches. In this paper, we have analyzed the feasibility of incorporating contextual information to a support machine and have evaluated its performances with reference to the traditional approaches. Accuracy improvement of the proposed approach may be attributed to the effectiveness in combining spatial and spectral information. © 2013 IEEE.
Sanjeeva G.N.,Indira Gandhi Institute of Child Health |
Gujjal Chebbi P.,Indira Gandhi Institute of Child Health |
Pavithra H.B.,Indira Gandhi Institute of Child Health |
Sahana M.,Indira Gandhi Institute of Child Health |
And 2 more authors.
Indian Journal of Pediatrics | Year: 2016
Objectives: To study the predictors of mortality and mortality rate in a clinical cohort of Children Living with Human Immunodeficiency Virus infection (CLHIV) from India. Methods: This retrospective cohort analysis of CLHIV aged between 2 mo and 18 y registered during January 2004 through December 2014 at Pediatric Centre of Excellence (PCOE), Indira Gandhi Institute of Child Health (IGICH), was conducted using standard data collection sheet. Demographic and clinical characteristics of all eligible children were analyzed. The primary outcome measured was mortality. The authors also analyzed the cause of death and baseline parameters associated with death to study the predictors of mortality. Results: Out of 1289 CLHIV registered in the PCOE during the study period, 834 (64.7 %) CLHIV, with or without antiretroviral therapy (ART) care, were included. The total time contributed by the study participants was 2872.8 child-years. The mortality rate in these children was 4.9/100 child-years. A significantly higher mortality rate of 28.2 % was found in children < 5 y, 38.6 % in children with advanced WHO clinical staging, 35.2 % among severely immunosuppressed children and 22.3 % in severely malnourished children. Tuberculosis accounted for 28 % of deaths. Univariate Cox regression analysis showed treatment status, age <5 y, baseline WHO clinical stage 3 and 4, severe immune suppression and severe malnutrition were strongly associated with mortality. Conclusions: The mortality rate in the index study cohort was 4.9/100 child-years and tuberculosis was the major cause of death. Younger age, baseline advanced clinical and immunological staging were predictors of mortality. Even though mortality was significantly higher in Pre-ART children, treatment status was not found to be an independent predictor of mortality. © 2016, Dr. K C Chaudhuri Foundation.