本論文介紹一種使用微帶線(Microstripe line)所設計的平衡至單端雙通帶功率分波器(Balanced-to-Unbalanced Dual-Band Filtering Power Divider)，其通帶位置可依據不同的特性阻抗比來控制通帶的位置，中心頻率設計在2.25 GHz，為節省在微波系統中電路的面積，將帶通濾波器與功率分波器兩種元件合併成一個，傳統的功率分波器需要與帶通濾波器串接，若直接設計成具有濾波功能的功率分波器能將面積能夠大幅度的縮小，整體電路的大小為0.74λg×0.29λg，此外，在對稱面添加一E型殘段增強其共模抑制使其有良好的表現。
第一個電路是利用在奇模激發的狀態下，對稱面短路的特性，使用開路殘段及導納轉換器形成雙通帶的濾波器，而在偶模激發的狀態下，我們可以在對稱面加入開路殘段將零點控制在通帶上提高共模抑制，兩通帶的操作頻率分別為1.25 GHz及3.25 GHz，阻抗比為2.6；藉由調整不同的阻抗比，可以設計出第二個電路，兩通帶的操作頻率分別為1 GHz及3.5 GHz，兩種形式在差模響應下的回波損耗在通帶內皆超過15 dB，偶模響應下共模抑制皆有超過55 dB的衰減，並透過選擇適當的電阻使電路具有良好的隔離度及阻抗匹配。

The proposed design of a balanced-to-unbalanced dual-band filtering power divider whose bands can be controlled by the different characteristic impedance ratio is introduced in using microstripe line by this thesis. The center frequency of the passband is 2.25 GHz. The bandpass filter and the power divider play an important role in the microwave system. Typically, these two devices are occupied excessive areas when they coexist in the radio frequency front end, we integrate each other to economize the area. The overall circuit size is 0.74λg×0.29λg, additionally, adding an E-type open stub at the symmetry plane to enhance common suppression.
Under the odd mode excitation, the first circuit combines open stub and admittance inverters to design a dual-band filter that uses the short character in the symmetrical plane. Also, in even mode excitation we can add an additional open stub to enhance common suppression by adjusting the characteristic impedance and controlling the transmission zero into two bands.The operating frequency is 1.25 GHz and 3.25 GHz and its characteristic impedance ratio are 2.6 which can design the other one by adjusting different characteristic impedance. The operating frequency is 1 GHz and 3.5 GHz. The return losses are greater than 15 dB under the odd mode excitation in both cases and more than 60 dB decay in common mode suppression under the even mode excitation. Finally, we select the right resistance and fine-tune for good in-band port matching and isolation.

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