雜亂介質對粗糙海面上方蒸發波導之電波傳播效應

Effect of Random Medium on Wave Propagation in Evaporation Ducts above a Rough Sea Surface

周詠翔(Yung-Hsiang Chou)

指導教授 ： 江簡富

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2013年)

https://doi.org/10.6342/NTU.2013.00460

摘要

在本篇論文中，採用了傅立葉分離步階法模擬並分析在蒸發波導下的電波傳播，並考慮了粗糙海面和空氣雜亂介質的效應。本文採用了Miller-Brown 的修正因子來模擬粗糙海面的效應，並使用了二維Kolmogorov 湍流頻譜去模擬空氣中雜亂介質造成的折射率擾動，二維的Kolmogorov 湍流頻譜是從原始的三維形式經由Wiener-Khinchin 理論推導而出，同時考慮了渦流外尺度的非等向性。為了分析在不同天氣情況下的傳播情形，本文推導了在不同天氣情況下的平均修正折射率、渦流外尺度以及折射率擾動的結構常數模型。本文展示了模擬和分析的結果，可以幫助瞭解在不同天氣情況下大氣湍流對於蒸發波導下傳播的效應。

關鍵字

蒸發波導 ； 隨機介質 ； 大氣湍流 ； 分步傅立葉

並列摘要

The split-step Fourier (SSF) propagation algorithm is applied to analyze the propagation properties in evaporation ducts above a rough sea surface, with random medium in the
ducts. The scattering effect of the rough sea surface is modeled with an effective reflection coefficient, including the Miller-Brown correction factor for surface roughness. The turbulence effect is simulated with a two-dimensional Kolmogorov power spectrum of refractive index fluctuation, which is derived from the three-dimensional Kolmogorov power spectrum by the Wiener-Khinchin theorem, included the anisotropic effect of the outer scale. The average M-profile, the varying outer scale of turbulence, and the structure constant of the refractive index are categorized under different atmospheric conditions. Simulation results
are presented and discussed over all the atmospheric conditions to better understand the effect of random medium on the evaporation ducts.

並列關鍵字

evaporation duct ； random medium ； atmospheric turbulence ； split step Fourier

參考文獻

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