12440

11388

كارشناسي ارشد

مخابرات - ميدان

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1395

هفده، 122ص.: مصور، جدول، نمودار

ص. ع. به فارسي و انگليسي

ذاكر حسين فيروزه، ابوالقاسم زيدآبادي نژاد

1396/03/02

كتابنامه

برق و كامپيوتر

مهندسي برق و كامپيوتر

ID11388

123Design Analysis and Fabrication of AMC Structures for RCS Reduction Bahare Zaki b zaki@ec iut ac ir 2017 1 14 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Dr Zaker Hossein Firouzeh zhfirouzeh@cc iut ac ir Dr Abolgasem Zeidabbadi Nezhad zeidabad@cc iut ac irAbstractOne of the best ways to reduce the radar cross section is use of AMC structure The mainadvantage of this method is low thickness and volume the flatness wide bandwidth lowcost and minimal dependency to polarization and angle of incidence In this thesis three general checkerboard AMC surfaces are designed for RCS reduction The first checkerboard AMC surface uses foam and the RT5880 substrate includes squarepatch ringed and cross element that are out of phase with each other over the frequencyband of 5 84 17GHz These elements are implemented in primary and completed structure The primary structure in which each block contains 4 4 elements has the bandwidth of52 75 In order to increase the frequency bandwidth completed structure with 5 5elements in each block is implemented This structure bandwidth is 80 67 By studyingthe FMB is observed that the completed structure has bandwidth more than 66 forincident angles that are smaller than 40 The second checkerboard AMC surface isdesigned on foam and RO4003 substrate It is cheaper than the first structure and itselements are implemented with little change in geometric parameters of the first structure These elements are out of phase with each other over the frequency band of 4 97 17 15GHz In order to increase the frequency bandwidth and reducing the amount of FMB thethird structure is implemented in aperiodic pattern which contains rectangular and squareblocks Aperiodic pattern is implemented by using RT5880 and RO4003 substrate Thecompleted structure with RO4003 substrate is fabricated and RCS reduction ismeasured The measured results are in good agreement with the corresponding simulations The advantages of structures that presented in this thesis are large frequency bandwidth sothat frequency range includes frequencies less or more than 10 GHz Another advantage isthe simplicity of AMC structures so that all metal parts of element lying on one substrate Also structures are minimal dependence to the angle of incidence and polarization over awide frequency range of operation In this thesis equivalent circuit of FSS structure composed of square patches ringed wasderived and implemented in MATLAB and the results that obtained for differentdimensions and different frequencies confirmed the results in CST software Keywords RCS reduction AMC structures Bandwidth Equivalent circuit

ذاكر حسين فيروزه، ابوالقاسم زيدآبادي نژاد