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Article
System Response Analysis of Linear Time Invariant Multistage Feedback Amplifier Network
تحلیل استجابةِ نظام شبكةِ مضخ مّ تعلیقاتِ الوقتِ الخطي المتعددة المراحل الثابتة

Author: Muneer Aboud Hashem
Journal: University of Thi-Qar Journal for Engineering Sciences مجلة جامعة ذي قار للعلوم الهندسية ISSN: 26645564/26645572 Year: 2011 Volume: 2 Issue: 4 Pages: 96-115
Publisher: Thi-Qar University جامعة ذي قار

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Abstract

The analysis of voltage series multistage feedback amplifier network is achieved by evaluating the nodal admittance matrix of the equivalent circuit representing the replacing of each transistor in a stage by its high frequency small-signal model and the performing of thehigh order voltage transfer function of the system. The main reasons of treating such a wideband amplifier network are of its stabilized voltage gain and its ability to amplify the pulses occurring in a television signal. The frequency response of the system is calculated and confirmed. System dynamics and variation of input signal are obtained by calculating the response of a continuous time system. The discrete-time equivalent to the analogue system allows the system designer to choose an appropriate pulse transfer function to investigate the performance of the system suitable for a given specifications and requirements. The software powerful MAT-LAB version 7.2 techniques is used for treating the single expression transferfunction obtained by assigning numerical values and the response of the system in time andfrequency domain.

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Article
ACTIVE FILTERS SYNTHESIS TO SIMULATED LADDER NETWORKS AND FEEDBACK CIRCUITS
تصميم دوائر المرشحات الفعالة لمحاكات الدوائر السلمية ودوائر التغذية العكسية

Author: Muneer Aboud Hashem
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2017 Volume: 21 Issue: 4 Pages: 171-183
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

An important feature in the design of passive and active filters networks is the method of the analysis employed. The purpose of this work is to synthesis two active low pass filters, the first is doubly terminated sixth order RLC passive ladder network and the second is multiple feedback network. The analyzing of the ladder network is achieved using graph-theoretic approach and the simulation is realized via MATLAB software tool version 8.1.0.604(R2010a) using Butterworth values for a corner frequency of ω_C=1 "MHz" . A confirmation of results is achieved by nodal analysis and numerical analysis using Newton-Raphson method, respectively. The synthesized complete circuit requires 14 operational amplifiers and uses voltage subtractors and non-inverting integrators as building blocks with capacitors and inductors values evaluated from choosing R=1 "kΩ" as an arbitrary value. For the second network, an RC passive circuit is used, the feedback and feedforward transfer function are obtained using the transformed T-network. The elements values of an active network are computed by considering a corner frequency of ω_C=10 "kHz" .

ان الخاصية المهمة في تصميم دوائر المرشحات الخاملة والفعالة هي طريقة التحليل المتبعة. الغرض من البحث تصميم دائرتين لمرشح تمرير منخفض فعال الاولى هي الدائرة السلمية الخاملة التي تستخدم المقاومات والملفات والمتسعات ذات النهايتين ومن المرتبة السادسة، اما الدائرة الثانية فهي متعددة التغذية العكسية. تم تحليل الدائرة السلمية باستخدام أسلوب نظرية البيانات وطريقة المحاكات تم انجازها عبر اداة المحاكات البرمجية MATLAB النسخة 8.1.0.604(R2010a) باستخدام قيم Butterworth لتردد رنيني مقداره 1 ميكاهرتز. وقد تم التحقق من النتائج عن طريق التحليل العقدي والتحليل العددي باستخدام طريقة Newton-Raphson على التوالي. ان الدائرة المصممة الكلية تتطلب أربعة عشر مضخم عمليات وتستخدم طارحات الفولتية والمكاملات الغير مقلوبة كلبنات اساسية، وان قيم المكونات تم حسابها باعتماد قيمة مقاومة عشوائية مقدارها 1 كيلو أوم. واما الدائرة الثانية فهي تتكون من المقاومات والمتسعات وقد تم التحليل عن طريق حساب دالة الانتقال للتغذية العكسية والتغذية الامامية باستخدام تحويلات الشبكة T . وقد تم حساب قيم المكونات باعتبار التردد 01 كيلو هرتز


Article
Static Characteristics of n+-n-p-p+ Silicon IMPATT Diode

Author: Muneer Aboud Hashem منير عبود هاشم
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2009 Volume: 13 Issue: 2 Pages: 144-161
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

To optimize device performance, theoretical analysis for static characteristics of an
n+-n-p-p+ silicon IMPATT diode with a deep junction from the surface and a diffused
junction in the n-p layer is presented. The doping profile in the (n) layer is considered to be
a Chebyshev orthogonal polynomial form, the diffusion coefficient is concentration
dependent, and the junction depth varies according to the diffusion time. The most
important characteristics such as the electric field distribution, potential distribution, and
excess noise factor are treated numerically using Newton's method and the introduction of
MATLAB version 6.1. Furthermore, response speed and the figure of merit, the cw output
power, are treated. It is found that the electric field and the potential are both increased
with increasing junction depth because of the increase in both the depletion layer width
and the impurity gradient. The excess noise factor is enhanced with deeper junction since
the maximum field is in its highest value. The response speed and the output power are
decreasing with wider depletion width and can be enhanced using moderate junction
depth.

يعرض البحث التحليل النظري للخواص الساكنة للثنائي السيلكوني الذي يعتمد اسلوب تأين الاصطدام و زمن انتقال حاملات التيار (IMPATT) والمتكون من التركيب ( n+-n-p-p+) للوصول الى الاداء الامثل لعمل الثنائي .الثنائي ممثل بملتقى انتشار بين طبقتي (n ) و (p ) عميق عن السطح. ان شكل الاشابة في طبقة (n ) ممثل بشكل دالةمتعددة الحدود متعامدة ،كما ان معامل الانتشار يعتمد على تركيز طبقة (n ) وعمق الملتقى يتغير تبعا لزمن الانتشار.ان اهم الخواص لهذا الثنائي كتوزيع المجال الكهربائي وتوزيع الجهد ومعامل الضوضاء الزائدة قد تم معالجتها باعتماد اسلوب التحليل العددي باستخدام طريقة Newton وتقديم ال MATLAB النسخة 6.1 لمعالجة العلاقات الرياضية. والابعد من ذلك، تم تحليل كل من سرعة الاستجابة ومعامل الجودة الذي هو قدرة الاشارة المستمرة الخارجة. وقد لوحظ ان المجال الكهربائي والجهد تتناسبان طردياً مع عمق المفرق بسبب الزيادة في كل من عرض منطقة الاستنزاف وازدياد هبوط تركيز الشوائب. كذلك يمكن تحسين معامل الضوضاء الزائدة باستخدام مفرق عميق بسبب وصول المجال الكهربائي الى اعلى قيمة له. ان سرعة الاستجابة و القدرة الخارجة تقل باستخدام مفرق عريض و لكن يمكن تحسينها باستخدام عمق مفرق معتدل.

Keywords


Article
QUANTUM EFFICIENCY OF A p-υ-n Si PHOTODETECTOR
الكفاءة الكمية للكاشف الضوئي n-υ-p سليكون

Authors: Mohammad Shihab Ahmmed --- Muneer Aboud Hashem
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2015 Volume: 19 Issue: 6 Pages: 130-143
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The quantum efficiency of a silicon p-υ-n photodetector is present. The analysis to obtain the quantumefficiency takes a uniform doping concentration in each layer into consideration. The theoretical treatment aims toinvestigate the effect of device parameters on the efficiency. Three different cases of the incident light wavelengthshave been considered; short wavelengths, medium wavelengths, and long wavelengths. There is no wavelength rangebetween them, but when the most of the incident light (about 63% or more) absorbed near the surface, it is calledshort wavelength, and when most of the light absorbed in υ-layer, it is called medium wavelength else called longwavelength.A high quantum efficiency at the wavelength of interest, combine with its low operating voltage andcapability, make this detector a promising for use in communication systems and computer interconnections.Highspeed silicon p-υ-n photodetector operates at 700 nmwavelength is reported. By using a reverse bias voltage tocontrol υ-layer width, a high quantum efficiency of 80% is attained corresponding to υ-layer width of 5.36 mand biasing voltage of 2.182 V.The results showed that the quantum efficiency is directly proportional to the widthof the υ-layer and biasing voltage. The results are achieved with the aid of MATLAB programming tool version8.1.0.604 R2013a.


Article
Photocurrents Mechanisms And Performance Considerations Of A Reach Through P+-N-N+ Silicon Photodiode

Authors: Fadhil Sahib Hasan فاضل صاحب --- Muneer Aboud Hashem منير عبود
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2010 Volume: 14 Issue: 4 Pages: 1-19
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The proposed model is a reverse-biased p+-n-n+ silicon photodiode which offers good quantum efficiency and high response speed suitable for photodetectors application. The theoretical analysis of the device is started with the evaluation of the built-in, reachthrough, and breakdown voltages. Photocurrent mechanisms theoretical treatment in each layer of the device are modeled. The effect of the surface recombination velocity and the absorption coefficient on the minority carries distribution in each layer within the device and on the overall device performance is presented. An effective and powerful modeling process of the mathematical foundations of the photodiode is performed with the aid of MATLAB R2008a version 6.5A. It is found that for a low reachthrough voltage, the concentration of the n layer should be reduced, the photocurrents increases as the width of the P+ and n layer increase at a relatively low surface recombination velocity and better absorption coefficient .A good quantum efficiency and high response speed of the photodiode in the wavelength region can be achieved by considering an optimum values of the effecting parameters in the n key layer of the device.

يتناول البحث نموذجاً مقترحاً للثنائي الضوئي السليكون p+-n-n+ ذو الانحياز العكسي . وهذا النموذج يقدم كفاءة كمية جيدة وسرعة استجابته عالية مناسبة لتطبيقات الكشف الضوئي . ان التحليل النظري للثنائي يبدأ من حساب فولتيات جهد الانتشار وجهد الوصول وجهد الانهيار. وقد تم نمذجةالمعالجات الرياضية للتيارات الضوئية كما تم دراسة تاثير سرعة اعادة الاتحاد السطحية ومعامل الامتصاص على توزيع حاملات الشحنات الاقلية ومجمل كفاءة الثنائي في كل طبقة. وانجز النموذج الرياضي للثنائي الضوئي باستخدام MATLAB R2008a النسخة6.5A بطريقة فعالة لتمثيل العلاقات الرياضية في مختلف طبقات الثنائي . وقد وجد انه لتفليل فولتية جهد الوصول يجب ان يكون تركيزعرض طبقةn وسرعة اعادة الاتحاد السطحية تأثير على كفاءة اداء الثنائي وباختيار قيم مثلى يمكن الوصول الى اداء جيد وسريع في منطقة الاطوال الموجية 0.5µm-0.82µm.


Article
ELECTRICAL AND OPTICAL EFFECTS OF Ag DOPANT ON ZnO THIN FILM BASED MSM UV PHOTODETECTORS

Authors: Mohammed Wesam Naji --- Ghusoon Mohsin Ali --- Muneer Aboud Hashem
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 4 Pages: 124-142
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This paper presents the fabrication, characterization and performance analysis of Zinc Oxide (ZnO) and Sliver doped Zinc Oxide (SZO) based interdigitated Metal–Semiconductor–Metal (MSM) Schottky barrier UV photodetectors. The ZnO and SZO thin films were grown on p-type silicon (Si) (100) substrates by sol-gel and spin coating technique. The three devices were fabricated using silver (Ag) as Schottky contact photodetectors based on un-doped ZnO, SZO with (2% and 4%) doping ratios. The structural and morphological properties of ZnO and SZO thin films were studied using Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and Atomic Force Microscopy (AFM). The optical and electrical properties for these films were studied using UV-visible and Hall effect measurements. With the applied voltage in the range of (-5 to 5 V) under dark condition, the values of the saturation current, barrier height, ideality factor, reach through and flat band voltages were extracted. Under UV illumination with different optical power levels ranging from (163.2µw -171.8µw) with a wavelength (254 nm), the values of the photo current, contrast ratio, responsivity, quantum efficiency, detectivity, and noise equivalent power were extracted. The SEM images showed a non-uniform distribution of the Ag dopants, these dopants were formed clusters and this clusters increased as the amount of Ag dopants increased. The mobility, carrier concentration, and roughness for the SZO films were increased as compared with undoped film. The optical band gap and the transmittance were decreased with increasing in the doping ratio. It was found that the saturation current decreased by a factor of 4, and 12 for the devices based on Ag doped ZnO (with 2% and 4 %) doping ratio. The sensitivity was significantly increased with increasing in doping ratio. This enhancement attributed to the roughness of the Ag doped ZnO thin films. Thus, this study revealed that the Ag doped ZnO films resulted in devices exhibiting better photoresponse as compared to those using un-doped ZnO thin films

Keywords

ZnO --- SZO --- ZnO:Ag --- MSM --- UV --- Sol-gel --- Ag.

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