Search or add a thesis

Advanced Search (Beta)
Home > Reflect Arrays for High Gain Applications

Reflect Arrays for High Gain Applications

Thesis Info

Access Option

External Link

Author

Shabbir, Tayyab

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2019

Thesis Completion Status

Completed

Subject

Telecommunication

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/12626/1/Tayyab%20Shabbir_Telecom%20Engg_2019_UET%28T%29_PRR.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727821110

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


This research work focuses on design and analysis of low-cost, single-layer broadband reflectarrays for X-band applications. Traditionally, parabolic reflectors and phased arrays were introduced to obtain the high gain. The disadvantages associated with traditional antenna types include: narrow bandwidth, high fabrication cost and complex feed networks. Recently, reflectarray antennas have been developed to overcome the disadvantages associated with parabolic reflectors and phased arrays. High gain reflectarray antennas are typically employed in radars, satellite communication and direct broadcasting applications. Four different type of delay-lines integrated reflectarray elements which include: single circular delay-line, pair of circular delay-lines, quad-meander and T-shape delay-lines are designed to obtain a broad linear phase range, high gain and good aperture efficiency. The reflectarray unit element performance is investigated in terms of phase range, Transverse Electric (TE) and Transverse Magnetic (TM) modes and far-field radiation patterns. The reflectarray unit element is analyzed by using circuit model technique and equivalent circuit results are verified through High Frequency Structure Simulator (HFSS™). The circuit model technique replaces the lengthy full-wave simulation of FEM method. This method provides fast and accurate calculation of electromagnetic parameters i.e. magnitude and phase range. The unit element shape and configurations are used to extract the lumped parameters and reflection characteristics. The reflectarray antenna system contains a feed horn antenna and an arrangement of phase shifting array elements. A hybrid Finite Element Boundary Integral (FEBI) method is used for electromagnetic modeling of reflectarray antenna system. The FEBI method provides accurate electromagnetic analysis of complex and medium-to-large sized structures. The reflectarray far-field radiation characteristics are obtained by using the hybrid FEBI method. The reflectarray antenna system model comprises of feed horn antenna and array of phase shifting elements. The feed horn antenna and array elements are designed separately. The effect of the incident angle, feed-to-diameter ratio and transmission modes can easily be considered in the FEBI based system simulations. The proposed reflectarray prototypes are fabricated and measured on a low-cost FR-4 substrate. The reflectarray antenna measurements are made in anechoic chamber. A gain of more than 20 dBi is realized for the proposed reflectarray configurations. The simulated and measured cross polarizations and side-lobe-levels are below -20 dB in all design configurations. More importantly, simulated results are in good agreement with the measured results.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

نیاز ؔفتح پوری

نیاز فتح پوری
گزشتہ مہینہ نیاز فتح پوری کی وفات اکیاسی (۸۱) سال کی عمر میں کراچی میں ہوگئی، معارف کو ان کی پچھلی زندگی میں ان کے بعض دلآزار مذہبی مضامین سے بڑا اختلاف رہا، لیکن انھوں نے اظہار انابت کرکے آخر میں مذہبی دلآزادی چھوڑ دی تھی، ان کے علمی ذوق میں بڑی رنگارنگی تھی، رسالہ نگار کے اڈیٹر ہونے کے ساتھ، مذہب تاریخ، سوانح، ناول نگاری، افسانہ نویسی اور شعر و ادب پر بھی طبع آزمائی کرتے رہے اپنے بعض مذہبی مضامین کی وجہ سے تو مطعون ہوئے، اچھے مورخ اور اچھے سوانح نگار بھی نہ ہوسکے، لیکن ان کا نام اچھے ناول نگار عمدہ افسانہ نویس اور شعرو ادب کے بلندپایہ نقاد کی حیثیت سے اردو زبان کی تاریخ میں خصوصیت کے ساتھ برابر لیا جائے گا، وہ اپنے رسالہ نگار کے ذریعہ جو علمی و ادبی خدمت انجام دیتے رہے وہ بھی ان کے اہم کارناموں میں شمار ہوگا، دعا ہے کہ اﷲ تبارک و تعالیٰ ان کی کمزوریوں کو اپنے دامن عفو میں جگہ دیں اور ان کو اپنی رحمت و مغفرت سے سرفراز فرمائیں، آمین۔
(صباح الدین عبدالرحمن، جون ۱۹۶۶ء)

 

نحو نهضة عربية إسلامية معاصرة

تسعى هذه الدراسة إلى التحديد التاريخي للنهضة العربية الإسلامية وسياقاتها وأسباب حدوثها، سواء منها السياسية أوالدينية أوالإصلاحية أو غيرها، والوقوف على أبرز روادها، ومناقشة أفكارهم، وتتبع مناهجهم، مع تدقيق النظر في المشاريع الإصلاحية التي قادوها في مراحل تاريخية حاسمة، هدفها استنهاض الأمة العربية والإسلامية من سباتها. وقد اعتمدت الدراسة على الجمع بين توليفة متكاملة من المناهج البحثية، خاصة منها المنهج الوصفي التحليلي والمنهج الاستقرائي والمنهج المقارن، وقد توصلت الدراسة إلى مجموعة من النتائج أهمها أن الأمة العربية والإسلامية لا زالت في نهضة وصحوة، ما دامت تسعى إلى تحقيق نفس الأهداف التي سعت إليها النهضة العربية السابقة، والتي لم تتحقق بعد، وقد أوصت الدراسة بمجموعة من التوصيات، تأتي على رأسها أهمية استجماع جهود الفاعل السياسي والمفكر والفاعل التربوي والمصلح الديني وعالم التقنية وغيرهم من الرواد، واشتغالهم بمنهج علمي واضح، قوامه استحضار مخرجات الإصلاحات السابقة دون الركون إليها، واستشراف المستقبل بتحدياته وآفاقه، لتخطيط مشاريع إصلاحية واقعية قابلة للتطبيق في البيئة العربية والمسلمة.

Impact of Leadership, Training and Compensation on Project Performance: A Case on Detail Design of Rehabilitation and Up-Gradation of Lower Bari Doab Canal LBDC System

Human Resource (HR) is one of the important aspects for any organization to accomplishing its management tasks in an effective manner. In this research, three human resource factors were studied and analysed for their impacton project performance. These factors are chosen on the basis of project natureand these factors are Leadership, Training &Compensation. The objectives of this research is to check the impact and significant correlation of leadership, training and compensation on the project performance also to find out the reasons of delay and how to boost-up the performance of this project. The case project has been delayed by 1.5 years. There is need to increase the efficiency of this project by addressing the three factors and analysing their significant correlation and impact on the project performance. Data was collected through questionnaire from companies who formed joint venture for this project and their departments specially HR department and different engineering departments which are working together on this project. This project needs strong leadership, effective training and comparatively high compensation for success. The results were described by using descriptive statistics, check the validity through reliability analysis, analyzed by Factor Analysis using Principal Component Analysis, Bivariate Correlation among the independent variables (Leadership, Training and Compensation) and dependent variable (Project Performance) and Regression analysis which shows results was reliable andmodel was best fit because the factors have a positive significant impacton the performance of the project. The multiple regressions shows the significant impact of independent variables (Leadership, training and Compensation) on dependent variable (Project Performance).