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| 2. |
- Massmoudi, N., et al.
(author)
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On the validity of the standard SPICE model of the diode for the simulation in power electronics
- 2001
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In: IEEE Transactions on Industrial Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0278-0046 .- 1557-9948. ; 48:4, s. 864-867
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Journal article (peer-reviewed)abstract
- A systematic study of the standard SPICE model of the diode in the case of simulations of power diodes in power electronic applications shows the limits of accuracy with respect to experiments. Therefore, the interest in such a model in power electronic applications is comparable to the high-low resistance model.
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| 3. |
- Mbairi, Felix D., et al.
(author)
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High frequency design and characterization of SU-8 based conductor backed coplanar waveguide transmission lines
- 2005
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In: Proceedings of the International Symposium and Exhibition on Advanced Packaging Materials Processes, Properties and Interfaces. - : IEEE conference proceedings. - 0780390857 ; , s. 243-248
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Conference paper (peer-reviewed)abstract
- The epoxy-based negative photoresist SU8 is widely used within the MEMS (Micro-Electro-Mechanical Systems) community, and is well known for its ability to form thick layers with high aspect ratios and for its chemical resistance. However, only a few papers have investigated the electrical properties of this material and mostly within the MEMS area or at lower frequency ranges.This paper presents the design and characterization of conductor-backed coplanar waveguide (CBCPW) transmission lines using SU-8 dielectric material. The coplanar transmission lines are carefully designed using EDA tools, and fabricated on a metallized glass substrate coated with SU-8 material. S-parameter measurements are performed from 45 MHz to 50 GHz using a vector network analyzer and a probe station. From these measurements, transmission line parameters such as characteristic impedance, attenuation constant, effective dielectric constant, loss tangent, etc, are determined. The design procedure, fabrication process and measurement results are described in this paper.To our knowledge, this is the first time the SU-8 material is characterized in Microelectronics using CBCPW transmission lines.
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| 4. |
- Mbairi, Felix D., et al.
(author)
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Microwave bandstop filters using novel artificial periodic substrate electromagnetic band gap structures
- 2009
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In: IEEE transactions on components and packaging technologies (Print). - 1521-3331 .- 1557-9972. ; 32:2, s. 273-282
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Journal article (peer-reviewed)abstract
- Novel microwave and millimeterwave (mm-wave) bandstop filters using artificial periodic substrate electromagnetic bandgap (EBG) are investigated in this paper. Three types of microstrip structures using periodically modified trace width, patterned dielectric substrate, and periodically modified ground plane are treated, respectively. By periodically modifying either the width of the conductor trace, the substrate height, or the dielectric constant of a standard microstrip transmission line, it has been possible to design microwave bandstop filter functions with wide stopband characteristics and reduced size, compared to conventional microwave/RF filter structures. Commercial electronic design automation (EDA) and computational electromagnetic tools such as Agilent's advanced design system (ADS) and CST Microwave Studio are used in the design and simulations of these filter structures. The effects of the physical parameters of the structures on the filter characteristic are studied. The design procedure and simulation results are described and possible applications of these filter structures are discussed in this paper. A particularly wide stopband is achieved by the circuits presented in this paper, which use only a few cell elements. A significant performance improvement of microstrip patch antenna has been observed by implementing one of the presented EBG periodic substrate structures.
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| 6. |
- Mbairi, Felix D.
(author)
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Some Aspects of Advanced Technologies and Signal Integrity Issues in High Frequency PCBs, with Emphasis on Planar Transmission Lines and RF/Microwave Filters
- 2007
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Doctoral thesis (other academic/artistic)abstract
- The main focus of this thesis is placed on high frequency PCB signal Integrity Is-sues and RF/Microwave filters using EBG structures. From the signal Integrity aspect, two topics were mainly discussed. On one hand, the effect of increasing frequency on classical design rules for crosstalk reduction in PCBs was investigated experimentally and by full-wave simulations. An emphasis was placed on the 3×W spacing rule and the use of guard traces. Single-ended and differential transmission lines were considered. S-parameter measurements and simu-lations were carried out at high-frequency (up to 20 GHz). The results emphasize the necessity to reevaluate traditional design rules for their suitability in high frequency applications. Also, the impacts of using guard traces for high frequency crosstalk re-duction were clearly pointed out. On the other hand, the effect of high loss PCB ma-terials on the signal transmission characteristics of microstrip lines at high frequency (up to 20 GHz) was treated. Comparative studies were carried out on different micro-strip configurations using standard FR4 substrate and a high frequency dielectric ma-terial from Rogers, Corporation. The experimental results highlight the dramatic im-pact of high dielectric loss materials (FR4 and solder mask) and magnetic plating metal (nickel) on the high frequency signal attenuation and loss of microstrip trans-mission lines. Besides, the epoxy-based SU8 photoresist was characterized at high frequency (up to 50 GHz) using on-wafer conductor-backed coplanar waveguide transmission lines. A relative dielectric constant of 3.2 was obtained at 30 GHz. Some issues related to the processing of this material, such as cracks, hard-skin, etc, were also discussed. Regarding RF/Microwave filters, the concept of Electromagnetic Band Gap (EBG) was used to design and fabricate novel microstrip bandstop filters using periodically modified substrate. The proposed EBG structures, which don’t suffer conductor backing issues, exhibit interesting frequency response characteristics. The limitations of modeling and simulation tools in terms of speed and accuracy are also examined in this thesis. Experiments and simulations were carried out show-ing the inadequacies of the Spice diode model for the simulations in power electronics. Also, an Artificial Neural Network (ANN) model was proposed as an alternative and a complement to full-wave solvers, for a quick and sufficiently accurate simulation of interconnects. A software implementation of this model using Matlab’s ANN toolbox was shown to considerably reduce (by over 800 times) the simulation time of microstrip lines using full-wave solvers such as Ansoft’s HFSS and CST’s MWS. Finally, a novel cooling structure using a double heatsink for high performance electronics was presented. Methods for optimizing this structure were also discussed.
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| 7. |
- Mbairi, Felix, et al.
(author)
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High frequency transmission lines crosstalk reduction using spacing rules
- 2008
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In: IEEE transactions on components and packaging technologies. - : IEEE conference proceedings. - 1521-3331 .- 1557-9972. ; 31:3, s. 601-610
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Journal article (peer-reviewed)abstract
- High-frequency transmission lines crosstalk reduction using spacing rules is treated in this paper. Two of the most popular planar transmission line configurations, namely microstrip and stripline, commonly used in printed circuit boards and radio frequency/microwave integrated circuits, are considered in this work. The trace separation between two adjacent transmission lines of each type is stepwise increased as function of the trace width. The single-ended transmission line structures are numerically investigated by a frequency-based 3-D full-wave electromagnetic analysis tool. A particular case using coated microstrip transmission lines has been fabricated, along with some calibration structures, to allow direct measurement and experimental analysis of crosstalk between the single-ended transmission lines. The test structures are characterized at high-frequency (up to 20 GHz) with scattering parameters using a vector network analyzer. The experimental results are compared with the simulation data, and some conclusions and suggestions on the impact and use of spacing rules for high-frequency crosstalk reduction between single-ended transmission lines are presented. These investigations emphasize the necessity of reevaluating classical design rules for their suitability in high-frequency applications.
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| 8. |
- Mbairi, Felix, et al.
(author)
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On the problem of using guard traces for high frequency differential lines crosstalk reduction
- 2007
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In: IEEE transactions on components and packaging technologies (Print). - 1521-3331 .- 1557-9972. ; 30:1, s. 67-74
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Journal article (peer-reviewed)abstract
- In this paper, the problem of using guard traces for reducing crosstalk between differential transmission line pairs is investigated, both experimentally and by full-wave electromagnetic (EM) simulations. Different cases of differential lines crosstalk are treated with and without guard trace separation between the differential line pairs. Coated microstrip printed circuit board test structures including thru-reflect-line calibration standards are designed and fabricated on a high frequency laminate material, allowing direct measurement of crosstalk between adjacent differential line pairs in the absence and in the presence of guard traces stitched with vias of regular spacing. The test structures are characterized with mixed-mode scattering parameters using a physical layer test system. Different configurations (of differential line pairs) without guard trace, with floating guard traces (which are terminated and nonterminated) and with a solid guard trace separation are investigated using a High Frequency Structure Simulator (a commercial full-wave 3-D EM simulation tool). The experimental data are compared with the simulation results, and some conclusions and guidelines on the effect of guard traces for alleviating crosstalk between differential transmission lines are presented.
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