In this work, two cone-inverted cylindrical and cross-hybrid dielectric resonator antennas are stacked and excited by the coaxial probe method with an operating standard resonant frequency of 5.438 GHz. A drawback of these standard Dielectric Resonator Antennas (DRAs) is their narrow bandwidth. For good antenna performance, a stacked DR geometry and a thick dielectric substrate having a low dielectric constant are desired since this provides large bandwidth, better radiation power, reduces conductor loss and nonappearance of surface waves. Many approaches, such as changing the shape of the dielectric resonator, have been used to enhance bandwidth. Using DRA, having the lowest dielectric constant, increases the bandwidth and the electromagnetic energy. In the current work, bandwidth improvement was significantly achieved by the proposed geometry by varying the antenna size. A novel hybrid DRA configuration is used to increase the bandwidth of the antenna to 89.27% and 149.23% due to cone-inverted cylindrical and cross-hybrid dielectric resonator antennas, respectively. The DRA is designed numerically via Finite Difference Time Domain (FDTD) method. Several parameters like return loss, input impedance (verified at ) and radiation pattern are calculated. Furthermore, the stacked-hybrid technique is used to enhance the antenna's performance which is useful for broadband communication and the demand of wireless.
المقدمة
تجدد الاهتمام بموضوع نوعية حياة العمل (Quality of life) الذي يرمز له اختصارا (QWL)، في السنوات الأخيرة الماضية، وبمطلع الألفية الثالثة على وجه التحديد، من قبل الباحثين الأكاديميين والمهتمين الممارسين في منظمات الأعمال، وذلك بوصفهم إليه بأنه أهم مصادر الرضا للعاملين، والعنصر المميز لبيئة عمل منظمة ما عن غيرها. وهنا، قد برزت الاضطلاع بالمسؤولية الأخ
... Show Moreانطلاقاً من ضرورات التجديد والتطوير لمجلتنا العزيزة، ستجرى اضافات عليها بين الحين والآخر، قد تتناول شكلياتها و/ او محتوياتها. والبداية ستكون بترجمة المقالات والبحوث التي تقع في اختصاصها من المجلات الاجنبية المرموقة عالمياً، فإختارت هيئة التحرير المقالات الخمسة التي سيرد ذكرها لاحقاً للقيام بترجمتها بأسلوب علمي يعطي للتصرف والاضافات حدوداً لتصبح مقبولة وسهلة على القراء. فالمهمة هذه وان كانت صعبة وتت
... Show MoreWe studied the effect of certain environmental conditions for removing heavy metal elements from contaminated aqueous solutions (Cd, Cu, Pb, Fe, Zn, Ni, Cr) using the bacterium Bacillus subtilis to appoint the optimal conditions for removal ,The best optimum temperature range for two isolate was 30-35○C while the hydrogen number for the maximum mineral removal range was 6-7. The best primary mineral removal was 100 mg/L, while the maximum removal for all minerals was obtained after 6 hrs of Cu element time and the maximum removal efficiency was obtained after 24 hrs of Cu element. The results have proved that the best aeration for maximum removal was obtained at rotation speed of 150 rpm/minute. Inoculums of 5ml/100ml which contained 1
... Show MoreLattakia city faces many problems related to the mismanagement of solid waste, as the disposal process is limited to the random Al-Bassa landfill without treatment. Therefore, solid waste management poses a special challenge to decision-makers by choosing the appropriate tool that supports strategic decisions in choosing municipal solid waste treatment methods and evaluating their management systems. As the human is primarily responsible for the formation of waste, this study aims to measure the degree of environmental awareness in the Lattakia Governorate from the point of view of the research sample members and to discuss the effect of the studied variables (place of residence, educational level, gender, age, and professional status) o
... Show MoreThis research has taken to the knowledge of the scope of applying the international specification of (ISO 10015) which is regarded to training by the Iraqi ministry of municipalities and public works ,in order to determine its training quality .By using the checklist made based upon the items of the specification ,after translating the English copy into Arabic ,which takes the indications of training depending on qualitative bases. The results of the analysis emphasized that occurred total average by comparison the evaluation of the training activity in the mentioned ministry with the international specification in all of its main items, which was (%55) ,and totally documented ,which finally refer to the existence of great
... Show MoreMRP is a system intended for the batch manufacturing of discrete parts including assemblies and subassemblies that should be stocked to support future manufacturing needs. Due to the useful information provided by MRP it has evolved into a Manufacturing Resources Planning, MRP II, a system that ties the basic MRP system to the other functional areas of the company such as marketing, finance, purchasing, etc. The objective of this research, which was conducted at the State Company for Batteries Manufacturing, is to test the performance of some popular lot-sizing techniques used within MRP II framework. It is hypothesized that the technique which minimizes the total inventory costs does no
... Show MoreInformation Technology has become one of the Most Prominent tools in the Era of Technology and Telecommunication of our Digital World. For that Reasons most Organizations had taken the tools Adapted to their Present and Future Directions and for the Improvement for it's Operations and Workability in Internal or External Enviroment. Consequently the Points of Strength Beats the Weakness and as Result of Increase Opportunities and Decrease the Threats Facing these Organizations. This Search has been made to test the Existence or not Existence role of the Information Network Technologies that Include {Internet and Extranet} in Application of Information Technology t
... Show MoreThe purpose of this paper is use the Dynamic Programming to solve a deterministic periodic review model for inventory problem and then to find the optimal policies that the company must uses in the purchase or production (in the practical application example the Al Aksa company purchase the generators from out side country).
The study aims at investigating the effectiveness of the Virtual Library Technology, in developing the achievement of the English Language Skills in the Center of Development and Continuous Education, in comparison with the individual learning via personal computer to investigate the students' attitude towards the use of both approaches. The population of the study includes the participants in the English Language course arranged in the Center. The sample includes 60 students who were randomly chosen from the whole population (participants in English Courses for the year 2009-2010). The sample is randomly chosen and divided into two experimental groups. The first group has learned through classroom technology; while the other group has l
... Show MoreThis study aims to assess the removal efficiency andestablish the BOD5 and COD statisticalcorrelation of the sewage flowing in Al-Diwaniyah wastewater treatment plant in Iraq during the study period (2005-2016). The strength of the influent wastewater entering the plant varied from medium to high in strength. High concentrations of BOD5 and COD in the effluent were obtained due to the poor performance of the plant. This was observed from the BOD5 /COD ratios that did not confirm with the typical ratios for the treated sewage. To improve the performance of this plant, regression equations for BOD5 and COD removal percentages were suggested which can be used to facilitate evaluation of liquid waste and optimal control process. The equations
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