藉由雙腔體系統決定物質的複數介電係數及導磁率

Characterizing the Complex Permittivity and Permeability with a Dual Cavity System

蔡政宏(Cheng-Hung Tsai)

指導教授 ： 張存續

國立清華大學/理學院/物理學系/碩士(2017年)

摘要

了解材料的特性有助於了解微波與材料的交互作用並提供工業研發的基礎,為了精確地量測材料特性,我們提出了新的量測方式-雙腔體系統-來改良目前常用的腔體微擾法,我們的系統能夠藉由疊代法減少材料引發的電磁場與腔體內部的電磁場之間的影響.我們準備了三種不同的複合材料,包含四氧化三鐵,銀,羰基鐵,分別與樹酯作混合,另外還準備了一種商用的鐵氧體.我們的系統能夠準確地量測這些複合材料的介電係數與磁導率並由這些複合材料回推材料本身在微波頻段的特性,在有外加磁場的條件下,我們也能清楚地測量到複合材料的磁化特性,對於商用鐵氧體,我們的量測也發現到不同的外加磁場會加強不同的共振模式.

關鍵字

雙腔體系統 ； 複合材料 ； 介電係數 ； 磁導率

並列摘要

Characterizing the electromagnetic properties helps us to understand the microwave-material interaction and to provide the foundation in engineering studies. For the precise measurement, the commonly used technique, cavity perturbation, suffers from the interplay between electric and magnetic fields. However, our proposed method, the dual-cavity system, can almost separate the influence of each field on the sample to characterize the relative complex permittivity and permeability, respectively. We prepared samples including three homemade epoxy-based composites (Fe3O4, silver, and carbonyl iron) and a commercial ferrite garnet. The complex permittivity and permeability of each composite can be determined and be well analyzed with the effective medium theories. With external magnetic fields, the electromagnetic properties of each composite change differently due to their own magnetism. For the ferrite garnet, distinct transverse electromagnetic (TEM) modes are enhanced with different magnetic bias fields.

並列關鍵字

Dual cavity system ； Composite material ； Complex permittivity ； Complex permeability

參考文獻

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