Frekans seçici yüzeyler, teknikleri ve uygulamaları
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Dosyalar
Tarih
2004
Yazarlar
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Yayıncı
Hatay Mustafa Kemal Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/openAccess
Özet
Bu çalışmada, belirli bir rezonans frekansına sahip periyodik kare halka ve dairesel halka Frekans Seçici Yüzeylerin, farklı dielektrik sabiti ve geliş açılarda iletim yansıma katsayıları hesaplanıp, kalkanlama etkinlikleri incelenmiş ve birbirleriyle karşılaştırılması amaçlanmıştır. Periyodik yarıklar içeren iletken levhalar veya periyodik yamalar içeren dielektrik yapılara frekans seçici yüzeyler (FSY) denir. Bu çalışmada, dielektrik katman üzerine kare halka ve dairesel halka geometrili iletken yapılar periyodik olarak yerleştirilmiştir. Bu yapıların periyodikliğinden dolayı elektrik ve manyetik alanlar, floquet modları cinsinden ifade edilmiştir. Sınır şartları, indüksiyon teoremi ve moment metodu kullanılarak, gelen düzlem dalganın bir iletken eleman üzerinde oluşturduğu bilinmeyen akım yoğunluğu, bulunmuştur. Bilinmeyen akım katsayıları elde edildikten sonra iletilen ve yansıyan alanlar bulunmuştur. İletilen alan ile gelen alan arasındaki ilişkiyle kalkanlama etkinliği hesaplanmıştır. Kare halka ve dairesel halka frekans seçici yüzeylerin, geliş açısı ve dielektrik sabitinin farklı değerleri için kalkanlama etkinliği incelenip birbirleriyle karşılaştırılmıştır. Elde edilen veriler sonucunda; her iki FSY yapının da kalkanlama etkinliği ve açısal kararlılıkları iyi denebilecek düzeyde ve dairesel halkanın kare halkaya oranla daha kararlı olduğu görülmüştür. 2004, 85 sayfa
In this study; it was aimed that the periodic square loop and ring element frequency selective surfaces were examined and compared each other at different dielectric constants and incident angles. Conductive screen perforated periodically with apertures or dielectric structures with periodically replaced patches are known Frequency selective Surfaces (FSS). In this work, square loop and ring type conductive structure were replaced periodically on a dielectric screen. Due to the periodicity, E and H fields were written as floquet modes. Unknown current density on a conductive element, it was caused by Incident plane wave, were obtained by using boundary conditions, induction theorem and moment method. After unknown current coefficients were found, transmitted and reflected fields were determined. The shielding effectiveness was calculated from relation between transmitted and incident fields. Square loop and ring element FSS were examined for the shielding effectiveness and compared each other at different dielectric constants and incident angles. As a result of obtained data; Both FSS structures have a good shielding effectiveness and sensitivity to incident angle. And ring FSS had been seen more stable then square loop FSS. 2004, 85 pages
In this study; it was aimed that the periodic square loop and ring element frequency selective surfaces were examined and compared each other at different dielectric constants and incident angles. Conductive screen perforated periodically with apertures or dielectric structures with periodically replaced patches are known Frequency selective Surfaces (FSS). In this work, square loop and ring type conductive structure were replaced periodically on a dielectric screen. Due to the periodicity, E and H fields were written as floquet modes. Unknown current density on a conductive element, it was caused by Incident plane wave, were obtained by using boundary conditions, induction theorem and moment method. After unknown current coefficients were found, transmitted and reflected fields were determined. The shielding effectiveness was calculated from relation between transmitted and incident fields. Square loop and ring element FSS were examined for the shielding effectiveness and compared each other at different dielectric constants and incident angles. As a result of obtained data; Both FSS structures have a good shielding effectiveness and sensitivity to incident angle. And ring FSS had been seen more stable then square loop FSS. 2004, 85 pages
Açıklama
Anahtar Kelimeler
Elektrik ve Elektronik Mühendisliği, Electrical and Electronics Engineering, Frekans seçici yüzeyler, kalkanlama etkinliği., Frequency selective surfaces (FSS), shielding effectiveness.
