11347

10423

كارشناسي ارشد

مخابرات ميدان

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1395

سيزده، 84ص.: مصور

محسن مداح علي

ابوالقاسم زيدآبادي نژاد، ذاكرحسين فيروزه

1395/04/28

مهندسي برق و كامپيوتر

ID10423

Design Simulation and Fabrication of Frequency Selective Surface for Angle Stability on the Wide Bandwidth at the X Band with TE and TM Polarization Mahdi Taghizadeh Kejani mahdi taghizadeh@ec iut ac ir Date of Submission May 09 2016 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Dr Mohsen Maddahali maddahali@cc iut ac irAbstractFrequency selective surfaces are one of the examples of periodic structures that have various applica tions in military and industry fields in recent decades For example radome put on antennas and radars uses as filter for inappropriate signals In general these surfaces are in two types dipole and slot thattheir frequency response are band stop and band pass respectively However they are used as absorber polarizer reflector and etc in other designs A lot of factors affects how frequency selective surfaceswork including these factors can be mentioned the element shape dielectric materials and thickness the cell size the grid in which the cell is and etc Because of different effects of these factors on fre quency selective surfaces each is considered individually in designing process Like other structures frequency selective surfaces have some limitations that some of the most important ones are bandwidth dimensions resonant frequency and bandwidth stability under variations of incident angle and polariza tion and grating lobe frequency In these years frequency selective surfaces designers have been tryingto improve and eliminate these limitations and use these surfaces in other industries Methods used toimprove their performance like adding active and lumped elements cell miniaturization three dimen sional frequency selective surfaces and etc have lessened some of aforementioned limitations partly But each of these methods has lessened one or two of these limitations and in some cases they havemade some new problems In this research a new method has been presented to design frequency selective surfaces In this methodin order to design band pass filters non resonant elements and dipole shape of frequency selective sur faces are used instead of slot shape The most important advantage of the method is to increase band width stability to incident angle which has been one of basic limitations of frequency selective surfaces Therefore two kinds of these frequency selective surfaces are designed that in the first case using squareelement the bandwidth is obtained 12 71GHz at the center frequency 12 24GHz and the angle is stable

محسن مداح علي

ابوالقاسم زيدآبادي نژاد، ذاكرحسين فيروزه