70年代後，由於印刷電路板技術日益成熟，且微帶形天線輕小薄等優點，越來越受到研究人員的青睞，微帶型天線為在具有接地導體的介質基板上附加導體貼片而形成的天線，可利用微帶線或同軸線來當饋入源，所激發的電磁場透過貼片與接地板之間的狹縫而輻射，透過在天線貼片上的刻槽造成等效電流路徑長短的改變，會影響天線工作頻率的表現或在不同頻率分歧出不同方向的極化。而利用接地線造成天線金屬貼片面與接地面短路，同樣可以達到天線工作頻率的偏移，以及不同極化表現
在天線設計裡，不同的應用方面需要不同的極化，因此極化的調整是天線設計中一個關鍵的部分，利用在天線貼片上切割狹縫，或是利用金屬線將天線貼片面與接地面短路位置改變，我們可以分歧出不同線性極化的模態。
本論文探討當接地型天線與刻槽型天線結合時，對模態以及極化特性的影響。其結構主要有兩種，其中一種為破壞性接地刻槽型天線，可以得到在不同頻率時兩個線性極化方向的分歧模；另一種為建設性接地刻槽型天線，由於兩個極化方向的基態模彼此間的相位差，我們可以在基態模頻率得到圓極化的特性。量測與模擬的特性一致，只有電路板在製作過程中的誤差所產生頻率些微位移，位移量約為0.06GHz，誤差2.5%。
未來可以利用PIN二極體來取代金屬接地線，利用PIN二極體偏壓，造成貼片層與接地層短路或斷路，來達成線性極化與圓極化間的快速切換(polarization-agile)。另外利用天線結構改變，如刻槽長短、貼片長度改變或視接地位置，利用建設性和破壞性特性，據此可以設計多樣化的無線產品應用。

The study discusses the polarization-frequency diversity for microstrip patch antennas by grounding pin and slot. Clearly, the specific polarization design is one of significant issues for radio frequency applications. The effective current path can be varied via slot or grounding pin so that the operating frequency are shifted higher or lower. The TM10 and TM_01 modes are excited with the feeding probe closed diagonal line on a square patch. The hybrid linear polarization also can be separated into two individual linear polarization governed by TM_10 and TM_01 modes or be transformed to circular polarization by slot and grounding pin applied.
In this paper, we discuss the characteristics of mode and polarization when both slot and grounding pin are applied. There are two main structures. One of these structures is destructive type which has two polarizations governed by TM_10 and TM_01 modes. The other structure is constructive type which has circular polarization based on the original resonant mode. These designs demonstrate the circular-polarization performance and linear-polarization diversity with only one layer and a single feed. The simulation result matched the theoretic proof and real instrument measurement. The overall tolerance is less than 3%.The study could deliver the valuable principle for multi-mode and switchable polarization RF components design.

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