本研究的主要目的是以修正後的傳統點波源模型描述電磁波穿過完美導體(PEC)上之次波長孔洞後所形成的遠場繞射場分佈。透過建構新點波源模型，希望有助於發現更多次波長波動力學獨特的現象，並且以簡單明確的方式描述，甚至能應用這些發現。

先前驗證了傳統點波源模型可以用於二維次波長單狹縫，本研究進而將此二維系統以三維環境模擬，而後更進一步縮短狹縫成為一個次波長方形孔洞，在層層遞進的過程中，每一個結構變化的轉折處皆為瞭解問題之關鍵。最後，透過對繞射電磁場在整個空間中分佈的瞭解，我們成功建立起頗為符合電磁波數值模擬的新點波源模型。

We develop a new point source model to describe the far-field diffraction patterns caused by an electromagnetic
wave going through a sub-wavelength rectangular aperture pierced in a perfect electrical conductor (PEC) film. Through the whole process, we hope to understand more about sub-wavelength wave mechanics.

We verified that the conventional point source model could be applied to a system of two-dimensional sub-wavelength single slit. We then study the same structure with three-dimensional Finite-Difference Time-Domain (FDTD) simulation. Then, we change the slit structure to a rectangular hole in sub-wavelength scale. The different results coming from different structures tell us what happened while the light is diffracted by a sub-wavelength hole. Together with the study of the distribution of electric and magnetic fields in free space, we develop a new point source model to be consistent with the FDTD simulation.

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