Armağan Demet Sevil ŞAHİNKAYA, Eren ERDOĞAN

Elektromanyetik dalgaların rezistif yan duvarlı bir oluktan saçılımı

Bu çalışmada, kanal düşey duvarları farklı rezistif yüzeylere sahip, yatay duvarları mükemmel iletken ve bu duvarların arası elektriksel ve manyetik olarak geçirgen malzemelerle doldurulmuş bir oluktan E2 polarize düzlemsel dalgaların kırınımı incelenmektedir. Problem sınır koşulları kullanılarak formüle edilmiş ve Fourier dönüşümü yardımıyla üçüncü türden bir modifıye Wiener-Hopf denkleme indirgenmiştir. Bu denklemin ayrıştırılması sonucunda ortaya, ikinci tipten iki adet Fredholm integral denklemi çıkmıştır. Elde edilen denklemlerdeki integraller asimptotik olarak değerlendirilmiştir ve sonsuz boyutlu cebirsel denklem sisteminin çözümü sayısal olarak yapılmıştır. İncelenen yapıya ilişkin saçılan alanın ayrıntılı analizi semer noktası yönteminden faydalanılarak yapılmıştır. Fiziksel parametrelerin değişiminin kırınım olayına etkisi sayısal verilerle gösterilmiştir.

Scattering from a rectangular groove with resistive walls

The analysis of electromagnetic wave scattering from rectangular grooves has received much attention recently in connection with the prediction and reduction of the radar cross-section of a target. There have been a number of investigations on the scattering by grooves based on high frequency (ray-based) and low frequency (numerical) techniques as well as a hybrid ray. The Wiener-Hopf technique is one of the powerful rigorous approaches for analyzing wave scattering associated with canonical geometries. In this study plane wave diffraction from a rectangular groove having resistive vertical walls with material loading is analyzed for $E_{z}$ polarization. The basic procedure adopted in this work is to take the Fourier transform of the reduced wave equation and apply the boundary conditions in the transform domain. This leads to a modified Wiener-Hopf equation (MWHE) of the third kind which can be reduced to a pair of simultaneous Fredholm integral equations of the second kind. The approximate solution of this MWHE involves two sets of infinite number of unknown constants satisfying two infinite systems of linear algebraic equations. The scattered field is evaluated by taking the inverse Fourier transform and applying the saddle point method. Numerical results showing the effects of groove depth, vertical wall resistivity and dielectric loading on scattered field are presented.

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Anderson, I., (1979). Plane Wave Diffraction by a Thin Dielectric Half Pane, IEEE Transactions on Antennas and Propagation, 27, 584-589.
Barkeshli, K. ve Volakis, J. L., (1991). Scattering from Narrow Rectangular Filled Grooves, IEEE Transactions on Antennas and Propagation, 39, 804-810.
Bhattacharyya, A. K., (1995). High-Frequency Electromagnetic Techniques: Recent Advances and Applications, John Wiley & Sons, Inc., New York.
Büyükaksoy, A., Birbir F. ve Erdoğan E., (1995). Scattering Characteristics of a Rectangular Groove in a Reactive Surface, IEEE Transactions on Antennas and Propagation, 43, 1450-1458.
Büyükaksoy, A., Çevik, M. ve Uzgören, G., (1997). Scattering of Plane Waves by a Thick Half-Plane with Resistive Vertical Walls, AEÜ International Journal of Electronics and Communications, 51, 97-102.
Büyükaksoy, A. ve Uzgören G., (1999). Kırınım Problemleri, GYTE Yayınları, Gebze.
Chumachenko, V. P., Karaçuha E. ve Dumanlı, M., (1999). An analysis of TE-Scattering From Multiangular Groove in a Ground Plane, Journal of Electromagnetic Waves and Applications, 13, 381-396.
Chumachenko, V. P., Karaçuha E. ve Dumanlı, M., (2000). TM-Scattering From Multiangular Groove in a Ground Plane, Journal of Electromagnetic Waves and Applications, 14, 329-347.
Keller, J. B., (1962). Geometrical Theory of Diffraction, The Journal of the Optical Society of America, 52, 116-130.
Meixner, J., (1954). The Behaviour of Electromagnetic Fields at Edges, New York University Research Report, No. EM-72.
Mittra, R. ve Lee, S. W., (1971). Analytical Techniques in the Theory of Guided Waves, The MacMillan Company, New York.
Noble, B., (1958). The Wiener-Hopf Techniques, Pergamon, London.
Park, T. J., Eom, H. J. ve Yoshitomi, K., (1993). An Analysis of Transverse Electric Scattering from a Rectangular Channel in a Conducting Plane, Radio Science, 28, 663-673.
Senior, T. B. A., (1979). Scattering by Resistive Strips, Radio Science, 14, 911-924.
Senior, T. B. A., (1985). Combined Resistive and Conductive Sheets, IEEE Transactions on Antennas and Propagation, 33, 577-579.
Senior, T. B. A. ve Liepa, V. V., (1984). Backscattering from Tapered Resistive Strips, IEEE Transactions on Antennas and Propagation, 32, 747-751.
Senior, T. B. A. ve Volakis, J. L., (1987). Sheet Simulation of a Thin Dielectric Layer, Radio Science, 22, 1261-1272.
Yoshidomi, K., (1984). Scattering of an Electromagnetic Beam Wave by Rectangular Grooves on a Perfect Conductor, Transaction of Institute of Electronics Information and Communication Engineers in Japan, E67, 447-448.