本篇論文提出一個利用色散延遲線實現的微型化枝幹耦合器。色散延遲線主要由訊號層之並聯開路殘段及其對應的接地層槽線所構成，其接地層槽線可補償訊號層並聯殘段所產生之零點以使訊號層並聯殘段之|S21|頻率響應成為全通響應。透過在尺寸縮小後的枝幹耦合器加上上述所提的互補式傳輸線結構，可以讓各埠之間的相位差與縮小前的傳統枝幹耦合器相同，因此所設計的微型化枝幹耦合器能夠有和傳統枝幹耦合器相同的特性。
論文中設計了兩個頻率分別在500 MHz和1 GHz的微型化枝幹耦合器，電路皆使用 ROGERS RO4003基板，基板厚度為 32 mils，介電係數為3.55，金屬厚度為35 μm，損失正切值為0.0027。頻率在500 MHz 的微型化枝幹耦合器電路面積縮減了59.6%，頻率在1 GHz的微型化枝幹耦合器則縮減了48%，量測的結果與模擬結果相符。

In this thesis, a miniaturized branch-line coupler using dispersive delay line is presented. The dispersive delay line includes shunted open stubs in signal plane and slot-line of the corresponding stubs in ground plane. Transmission zeros of shunted open stubs can be convert to an all-pass response of |S21| by the slot-line of corresponding stubs. By adding the complementary configuration to a reduced branch-line coupler, the phase difference between ports remains the same with the original branch-line coupler. Thus the miniaturized branch-line coupler performs the same characteristic with the conventional branch-line coupler.
This thesis presents two different miniaturized branch-line couplers separately at 500 MHz and 1 GHz. Their circuits are both built on the ROGERS RO4003 substrate with substrate thickness of 32 mils, conductor thickness of 35μm, and loss tangent of δ = 0.0027. The miniaturized branch-line coupler at 500 MHz has a size reduction of 59.6%. The miniaturized branch-line coupler at 1 GHz has a size reduction of 48%. The measurement results are in good agreement with the simulations.

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