本研究旨在推導一套可通用於多層介質下計算材料吸波性能的模型，特別是在電磁波斜向入射材料的情況下。隨著5G技術的普及，電磁波吸收材料在減少設備之間的電磁干擾（EMI）方面變得愈加重要。這些材料不僅需要具備良好的吸波性能，還需滿足輕質、薄層、成本低廉、堅固耐用等要求。然而，現今的吸波材料文獻大多僅討論單/雙層吸波材料的吸波性能，並且只計算了垂直入射的反射損耗，未考慮電磁波斜向入射對材料的影響。
為了解決這個問題，本研究根據傳輸線理論推導了一套完整的電磁波於多層介質中的傳遞矩陣通式，並透過傳遞矩陣將反射係數、透射係數以參數形式寫出。接著，我們將推導結果撰寫成MATLAB程式碼，使用樣條插值法（spline）和平滑數據的方法重建目標材料的數據，並透過輸入材料層數、背板阻抗、目標頻段、入射角、各層厚度等相關參數於程式中，即可得到該材料的吸波性能結果。同時，本研究使用了不同材料配置、不同極化與入射之文獻進行數據重建與計算驗證，在調整並完善程式碼的同時，進一步佐證了程式的可靠性。最後，本研究針對過去實驗室研究的幾種吸波材料配置，使用MATLAB將材料數據與垂直入射計算結果重建，並加上了斜向入射的反射損耗結果，完善過往研究的同時，也得到了材料新的可能性。
本研究為未來的元件開發和優化提供了重要的理論基礎與計算工具。使用程式碼透過改變計算參數，可以觀察不同參數對吸波性能的影響；在實作層面提供了一個快速且可靠的背景理論計算，避免大量無效實驗的同時，也提供了一個可信的結果與實驗量測對照。這對研究吸波材料的特性以及濾波器設計發展具有重要價值，為研究電磁波吸收材料提供了堅實的基礎。

In this study, we derived a comprehensive formula for multilayer absorbing materials based on transmission line theory. This formula calculates the reflection loss of absorbing materials backed by metal, using the measured frequency-dependent complex dielectric constant, complex permeability, material thickness, number of layers, and electromagnetic wave incidence angle as input parameters. The formula was implemented in MATLAB, and the results were validated by comparing them with reflection loss calculations from previous research under normal incidence. Finally, using the completed code, we calculated the reflection loss of absorbing materials left({m Ni}_{0.5}{m Zn}_{0.5}ight){m Fe}_2O_4/Epoxy,({m Ni}_{0.35}{{m Cu}_{0.3}Zn}_{0.35}){m Fe}_2O_4/CNF/Epoxy, {m BaFe}_{11}{{{(Mn}_{0.5}Cu}_{0.5}Ti)}_{1/2}O_{19}/CNF /Epoxy, ({m Ni}_{0.45}{{m Zn}_{0.45}Co}_{0.1}){m Fe}_2O_4/CNF /Epoxy, carbonyl iron (60 wt.%)/Epoxy and double-layer wave-absorbing material (Layer1: ({m Ni}_{0.4}{{m Zn}_{0.4}Co}_{0.2}){m Fe}_2O_4/Epoxy, Layer2: carbonyl iron (60 wt.%)/Epoxy) under oblique incidence. It is found that the({m Ni}_{0.35}{{m Cu}_{0.3}Zn}_{0.35)}{m Fe}_2O_4/CNF/Epoxy sample with a thickness of 5.3 mm at a center frequency of 5 GHz exhibited a maximum reflection loss of -37 dB in the transverse electric (TM) mode at an incident angle of 30 degrees. This study provides valuable insights into the characteristics of absorbing materials, advancing the design of multilayer absorbing materials and laying a strong foundation for future research on material samples.

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