Linearity measurements of Si/SiGe HBT using a large signal network analyzer and a harmonic load-pull setup

International audienceThis paper presents original multi-harmonic modulated load-pull measurements on a Si/SiGe HBT of STMicroelectronics technology. The original aspect is that the linearity, power and efficiency measurements are realized on an active load-pull test-bench associated with a large signal network analyzer. The aim of the measurements is to optimize and characterize the HBT excited by a CW and a two-tone signal. The comparison with the simulation lets to validate the models in large-signa

Linearity measurements of Si/SiGe HBT using a large signal network analyzer and an harmonic load-pull setup

International audienc

The locus of points of constant output VSWR around the load optimal impedance: evaluation of power transistors robustness

International audienceThis paper determines the locus of points of constant output voltage standing wave ratio (VSWR) around the load optimal impedance at the fundamental frequency. This resolution is very helpful to determine the power transistors robustness. To illustrate this, some measurements results are presented on a Si/SiGe HBT of STMicroelectronics technology. The measurements are realized on two multi-harmonic load-pull test-benches: one passive and one active

Time-domain calibrated measurements of wideband multisines using a Large-Signal Network Analyzer

International audienceThis paper presents a calibrated measurement technique that enables phase and magnitude measurements of wideband multisines. This study is based on the use of a large-signal network analyzer (LSNA) performing harmonic sub-sampling and a fine frequency grid (20 MHz) comb generator calibrated using a high-frequency 50-GHz equivalent-time sampling scope. This comb generator is used as a harmonic phase reference generator for the calibration of the LSNA. The research reported here is applied to L-band multisine measurements, but it can be extended to higher microwave frequencies. The motivation of this study is to measure the multipactor phenomena effect in output RF multiplexers of satellite payloads

Water access and attendance for diarrhea in primary health care centers,Gaza strip

International audienceWater access and sanitation has worsened in Gaza strip since the conflict between Israel and Palestine in January 2009. This study aimed to investigate the relationship between attendance for diarrhea to a Primary Health Care Center (PHCC) in Gaza strip and several potential risk factors including water access. A matched case control study with prospective data record was performed. Cases were patients attending a PHCC for diarrhea, and controls were patients attending for any other cause with no diarrhea within the previous three months or since birth. We matched 133 cases and 133 controls, for date of inclusion, age, gender. All patients attended PHCC and were included in January/February 2010. A stool analysis for bacteria and parasites was performed for cases. Of the 266 patients, 62% (166) have to buy water from a private provider. In multivariate analysis, four variables were independently predictive of diarrhea: public water access (OR: 0.046; 95% CI: 0.005-0.454; P=0.0083), poultry or rabbits at home, and presence of cooker at home. A bacterial cause was found in 5.5% (7) and Giardia duodenalis in 20% (26). Treatments did not comply with WHO recommendations. Efforts should be made to improve water access and to implement guidelines for a better management of diarrhea in Gaza strip. (C) 2011 Royal Society of Tropical Medicine and Hygien