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Article
On the Performance of a Microstrip Antenna Based UC-PBG Structures for UHF RFID Readers

Authors: Ali S. Jalal --- Marwa H. Jwair
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 5 Part (A) Engineering Pages: 480-487
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

Microstrip antennas suffer from low gain bandwidth product due to surface wave effects and aperture diffractions that limit their use for long-range communications. On top of that, the difficulty of achieving a pure circularly polarized radiation with high gain due to the feeding structure effects. This paper is subjected to design a gain enhanced circularly polarized patch antenna using Uniplanar Compact-Photonic Band Gap (UC-PBG) structu.res for UHF RFID applications. The patch is structured as truncated corners with cross slots at the centre mounted on an FR-4 epoxy substrate of 1.6mm thickness with an overall area of 188×188mm2. The UC-PBG is constructed of two layers; each is made of 7×7 unit cells, separated by 20mm mounted from the top of the patch at 30mm height. The unit cell characterizations are evaluated in terms of their S-parameters and dispersion diagram CST-MWS environment. The antenna shows a boresight gain of about 8.2 dBi at 915MHz with a front to back ratio (F/B) of 13dB. The benchmark enhancement in boresight gain after adding the UC-PBG layers is found to be 3.4 dBi with a radiation efficiency of 87%. Finally, an excellent agreement is achieved between the obtained measurements and numerical results.

Keywords

Circular polarization --- RFID --- UHF --- UC-PBG.


Article
Toward Plasmonic UC-PBG Structures based SWCNTs for Optoelectronics Applications
دراسة امكانية بناء هياكل حزم الفجوات الضوئية من مصفوفات انابيب الكاربون النانوية الاحادية الجدران نحو تطبيقات الكهروبصريات

Author: Taha A. Elwi طه احمد عليوي
Journal: Diyala Journal For Pure Science مجلة ديالى للعلوم الصرفة ISSN: 83732222 25189255 Year: 2018 Volume: 14 Issue: 1 - Part 1 Pages: 18-30
Publisher: Diyala University جامعة ديالى

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Abstract

In this paper, the possibility of performing UC-PBG layers that is constructed from a forest of Single Wall Carbon Nanotubes (SWCNT) are aligned vertically on a thin flat film of quartz is studied. Such study is concerned in plasmonic optoelectronic applications in the visible regime. The study is conducted to the numerical simulations based Finite Element Method (FEM), then, compared with measurements. Remarkable benchmarks are found in the performance of the proposed UC-PBG which can be summarized as: 1- excellent ability of focusing the light over a wide range of the visible bands, 2- low effective losses, 3- a miniaturized sizeof the numerical a preacher, 4- no spherical apparition due to the flat geometry. It is found the proposed UC-PBG shows an effective refractive indexvaries from 10 to 20 in Lorentz-Drude manner. The maximum induced power of the proposed UC-PBG is found to be around 450 nm. Nevertheless, the size of the proposed UC-PBG layer is 200nm×200nm. Finally, the obtained results are compared to another numerical analysis based on Finite Integral Technique (FIT). Excellent agreements are found between the two invoked numerical methods.

في البحث تم دراسة امكانية بناء وتصميم طبقات ال) UC-PBG ( من الأنابيب الكربونية النانوية ذات الجدرانالاحاديةال) SWCNT ( والمصففة عموديا على طبقة رقيقة من الكوارتز. هذه الدراسة تصب في تطبيقات الكهروبصريات بظاهرةالانتقال البلازمي. لقد أجريت الدراسة باستخدام المحاكاة العددية القائمة على طريقة ال) FEM (، ثم مقارنتها مع القياساتالعملية باستخدام التحليل الطيفي. لقد وجد عدة امور مهمة في أداء ال UC-PBG التي يمكن تلخيصها على النحو التالي: 1 -قدرة ممتازة لتركيز الأشعة خلال حزم واسعة من ضمن النطاق الضوء المرئي، 2 الخسائر الناجمة من هذه المصفوفات -كانت منخفضة جدا، 3 حجم الفتحة العددية مصغرة جدا، - 4 لا وجود للزيغ الكروي بسبب الشكل المسطح. تم احتساب -معامل الانكسار والذي كان يتراوح من 10 إلى 20 . ان أعلى حد لنفاذ الاشعاع كان عند 450nm . ومع ذلك، فإن مساحةطبقة ال UC-PBG هو 200×nm200nm . وأخيرا، تم مقارنة النتائج التي تم الحصول عليها باستخدام تحليل عددي آخرقائم على أساس تقنية ال) FIT ( حيث وجد اتفاق جيد جدا بين الطريقتين.

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