本論文主要係以「非對稱T型結構」及「雙線傳輸線」研製多型微型化環形耦合器。本論文主要分為兩大部份，第一部份主要使用非對稱T型結構研製兩款微型化環形耦合器。此兩款耦合器可分別縮小為傳統耦合器面積的3.9 %和4.48 %；接續結合長度縮減耦合器及非對稱T型結構，設計微型化環形耦合器，此耦合器之面積可縮小為傳統耦合器面積的5.55 %。
第二部份主要使用雙線傳輸線研製「功率等分」及「功率不等分」環形耦合器。因雙線傳輸線由兩條不等長之高阻抗傳輸線並聯而成，藉由高阻抗傳輸線較易彎折之特性，可有效縮小電路佈局面積。本論文所設計之「功率等分」耦合器佔傳統耦合器之21.87 %電路面積；「功率不等分」耦合器之面積則可縮小為傳統耦合器之41.5 %。

In this thesis, two guided-wave structures, namely “asymmetrical T-structures” and “dual transmission lines”, have been introduced, and then applied to realize compact planar ring couplers. Basically, this thesis consists of two main parts. The first part is using “asymmetrical T-structures” to design two miniaturized ring couplers. Two developed couplers only occupy 3.9 % and 4.48 % circuit sizes of the conventional structure, respectively. In addition, combining the reduce-length ring coupler and asymmetrical T-structures, the compact ring couplers can be realized with only 5.55 % circuit size of the conventional structure.
The other part mainly uses dual transmission lines to implement “equal power” and “unequal power” ring couplers. The dual transmission line is composed of two parallel-connected high-impedance lines with unequal electrical lengths. By taking advantages of the circuit layout flexibility, the ring coupler realized by dual transmission lines can be optimally miniaturized. The ring coupler with equal power division only occupies 21.87 % circuit size of the conventional structure, and that with unequal power division only occupies 41.5 % circuit size.

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