隨著科技日新月異，人類探測這個世界的方式已不再侷限於使用雙眼。從二次世界大戰開始，微波雷達技術蓬勃發展，打開了電磁波譜的另一個領域。如今微波波段，已經廣泛使用於各個層面，無論是日常生活的電器及行動通訊，或是用於國防及學術研究的遙測探勘、雷達探測等等，可說是與現今人類的生活息息相關。因此微波波段電磁波的行為研究，便日益顯得重要。 在遙測方面的應用，我們首先要考慮到的是電磁波對於偵測物的散射現象。電磁波的表面散射現象相當複雜，我們除了必須考慮粗糙表面所產生的散射之外，還必須考慮到介質的不均勻產生的介電係數變化。在此，我們使用多層介質(N-multi-Layered Medium)來簡化數學模式，假設不均勻介質為分層的均勻介質，並且利用數值方法(numerical methods)使問題簡化，進一步模擬出格林函數(Green’s Function)，用以求得散射場之場強。 本研究結果顯示，多層的非均勻介質所產生的散射效應是不能忽略不計的，並且和電磁波之極化具有相關性。 With new technology and science developing, human sense the world not only by use of eyes. Because of the applications of the technology of microwave radar, scientists and engineers opened a whole new field of electromagnetic spectrum since the World War II. Electromagnetic wave has been extensively used in communication and radar detection of targets. In wave propagation, a common problem occurs in describing the scattering at the interface between two media, such as the interfaces between air and ocean, air and soil air, and vegetation cover, etc. To some extent, all the interfaces will have some degree of roughness, which will complicate the scattering. The scattering of electromagnetic waves by lossy dielectric rough surfaces has broad applications because of the similarities to natural media. We use multi-layered media to simplify the problems about dielectric rough surfaces and simulate the Green Function by numerical method to compute the scattering field. The simulations show that the effect of the inhomogeneous layered medium is non-negligible and is polarization dependent.
