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Efficient Circuit and an EM Model of an Electrostatic Discharge Generator
Yousaf, Jawad,Park, Myeongkoo,Lee, Hosang,Youn, Jinsung,Lee, Daehee,Hwang, Chanseok,Nah, Wansoo [Institute of Electrical and Electronics Engineers 2018 IEEE transactions on electromagnetic compatibility Vol.60 No.4
<P>In this work, a new technique for an efficient, simple, and fast equivalent circuit and full wave numerical modeling of the electrostatic discharge (ESD) generator is presented. A novel circuit model of the NoiseKen ESD simulator is proposed based on the frequency domain measurement of the standard waveform calibration setup. The simple full wave electromagnetic model of the same generator, which requires much less computation resources, is also proposed using commercial CST Microwave Studio software. The reliability of the proposed models as an authentic ESD excitation source is validated through an example discharge application. The good agreement between the ESD reference waveform obtained through measurement, circuit model, and 3-D model of the generator is observed.</P>
Jawad Yousaf,Hosang Lee,Wansoo Nah 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5
This study presents states-of-the art overview of the system level electrostatic discharge (ESD) analysis and testing. After brief description of ESD compliance standards and ESD coupling mechanisms, the study provides an in-depth review and comparison of the various techniques for the system level ESD coupling analysis using time and frequency domain techniques, full wave electromagnetic modeling and hybrid modeling. The methods used for improving system level ESD testing using troubleshooting and determining the root causes of soft failures, the optimization of ESD testing and the countermeasures to mitigate ESD problems are also discussed.
System Level ESD Analysis - A Comprehensive Review II on ESD Coupling Analysis Techniques
Yousaf, Jawad,Lee, Hosang,Nah, Wansoo The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5
This study presents states-of-the art overview of the system level electrostatic discharge (ESD) analysis and testing. After brief description of ESD compliance standards and ESD coupling mechanisms, the study provides an in-depth review and comparison of the various techniques for the system level ESD coupling analysis using time and frequency domain techniques, full wave electromagnetic modeling and hybrid modeling. The methods used for improving system level ESD testing using troubleshooting and determining the root causes of soft failures, the optimization of ESD testing and the countermeasures to mitigate ESD problems are also discussed.
Yousaf, Nageen,Afzal, Sibtain,Hayat, Tehreem,Shah, Jasmin,Ahmad, Nafees,Abbasi, Rashda,Ramzan, Khushnooda,Jan, Rasul,Khan, Imran,Ahmed, Jawad,Siraj, Sami Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.22
Background: Vitamin D receptor (VDR) gene has been a subject of extensive pharmacogenetic research recently. Association studies between different types of cancers including prostate cancer (PCa) and VDR gene polymorphism have also been conducted. The objective of this study was to find possible associations between PCa and VDR gene polymorphisms in the Pakistani population. Materials and Methods: A total of 162 subjects, including prostate cancer patients and controls, were genotyped for Apa I, Taq I and Fok I polymorphisms in the VDR gene using allele specific PCR, PCR-RFLP and direct DNA sequencing. Allelic frequencies were tested for Hardy-Weinberg equilibrium and associations between the genetic markers and PCa were calculated using logistic regression. Results: Apa I CC genotype was found to have strongest association with PCa risk, and "A" genotype was found to have protective effect. Fok I and Taq I did not have appreciable levels of association with PCa, although Taq I "TC" heterozygotes seemed to have some protective effect. Similarly the "C" allele of Fok I also seemed to have protective effect. Conclusions: To our knowledge, this is the first report showing association between VDR gene polymorphisms and PCa in Pakistan. Our findings may be somewhat skewed because of small sample size and tendency of consanguineous marriages in Pakistani society; nevertheless, it shows the trend of association and protective effects of certain VDR gene polymorphisms against PCa.
A D-Band Waveguide-SIW Transition for 6G Applications
Altaf Amir,Elahi Manzoor,Abbas Syed Muzahir,Yousaf Jawad,Almajali Eqab 한국전자파학회 2022 Journal of Electromagnetic Engineering and Science Vol.22 No.4
In this work, a design of a transition from a standard D-band waveguide to substrate integrated waveguide (SIW) technology is presented for 6G applications. The waveguide is connected to an SIW by carving a slot at the bottom metal of the printed circuit board (PCB). A pair of vias is added to shift the inband null to a higher frequency, whereas a parasitic patch is used to improve impedance matching. A prototype of a back-to-back SIW transition is fabricated and measured using D-band VNA extenders. The measurement shows a −10 dB impedance bandwidth of 26.5 GHz (135–161.5 GHz) and a 3 dB bandwidth of 28 GHz (133.8–161.8 GHz). The transition can be integrated with a D-band antenna for 6G applications.
Hojin Jung,Kwangho Kim,Wansoo Nah,Jawad Yousaf 한국전자파학회JEES 2016 Journal of Electromagnetic Engineering and Science Vol.16 No.3
This work presents a new method for enhancing the performance of a dual band Planer Inverted-F Antenna (PIFA) and its lumped equivalent circuit formulation. The performance of a PIFA in terms of return loss, bandwidth, gain, and efficiency is improved with the addition of the proposed open stub in the radiating element of the PIFA without disturbing the operating resonance frequencies of the antenna. In specific cases, various simulated and fabricated PIFA models illustrate that the return loss, bandwidth, gain, and efficiency values of antennas with longer optimum open stub lengths can be enhanced up to 4.6 dB, 17%, 1.8 dBi, and 12.4% respectively, when compared with models that do not have open stubs. The proposed open stub is small and does not interfere with the surrounding active modules; therefore, this method is extremely attractive from a practical implementation point of view. The second presented work is a simple procedure for the development of a lumped equivalent circuit model of a dual band PIFA using the rational approximation of its frequency domain response. In this method, the PIFA’s measured frequency response is approximated to a rational function using a vector fitting technique and then electrical circuit parameters are extracted from it. The measured results show good agreement with the electrical circuit results. A correlation study between circuit elements and physical open stub lengths in various antenna models is also discussed in detail; this information could be useful for the enhancement of the performance of a PIFA as well as for its systematic design. The computed radiated power obtained using the electrical model is in agreement with the radiated power results obtained through the full wave electromagnetic simulations of the antenna models. The presented approach offers the advantage of saving computation time for full wave EM simulations. In addition, the electrical circuit depicting almost perfect characteristics for return loss and radiated power can be shared with antenna users without sharing the actual antenna structure in cases involving confidentiality limitations.