計畫名稱：微型高選擇度之威爾金森功率分配器
執行起迄：2011/08/01~2012/10/31
總核定金額：709,000元
中文摘要： 選擇度在傳統等功率威爾金森功率分配器中通常是不好的，本研究利用平行耦合線帶通濾波器來替換傳統等功率威爾金森功率分配器中之四分之一波長阻抗轉換器來達成高選擇度之功能，特別在此選擇度與傳統等功率威爾金森功率分配器串上濾波器於輸入端或各輸出端接近，但卻能節省兩段四分之一波長之阻抗轉換器的面積。然而，帶通濾波器在本論文所提出的功率分配器中，需要謹慎設計，因為有可能在某些條件下會不正常運作，例如，奇數階耦合線帶通濾波器並不適合在本研究所提出的功率分配器中，當作阻抗轉換器。此外，不好的選擇度在傳統的不等量威爾金森功率分配器中之各傳輸路徑上，通常是一個嚴重的問題，為了克服這項困擾，本論文將平行耦合線帶通濾波器當作阻抗轉換器並整合於不等量威爾金森功率分配器中當作通帶選擇器，藉此可達成各傳輸路徑所需之阻抗轉換與增加各通道之選擇度。本研究利用偶數階耦合線濾波阻抗轉換器，提出兩種新型的不等量威爾金森功率分配器，於第一種型式分配器中，將兩個濾波阻抗轉換器分別設計於兩個輸出端，藉著這種方式的設計，不僅可以在各傳輸路徑上獲得良好之選擇度，還可以在通帶以及較低與較高的截止帶獲得很好的隔離度。至於第二種型式的功率分配器是將各端埠之負載阻抗做妥善的設計後，僅需將一個濾波阻抗轉換器設計於輸出端，藉著該設計，兩個傳輸路徑皆可共享此濾波阻抗轉換器之濾波功能，在頻率響應上，也可達到有效的隔離度與良好的選擇度。
英文摘要： Conventional equal-split Wilkinson power dividers usually demonstrate poor selectivity. This study presents a novel type of divider with favorable selectivity using two coupled-line bandpass filters to replace two quarter-wavelength (λ/4) transformers of a conventional Wilkinson power divider. Notably, the selectivity of the proposed divider is similar to that of the conventional equal-split Wilkinson power divider with an additional filter placed before the input port or after each output port. Nevertheless, the proposed type of divider can avoid two λ/4 transformers, which are usually used in the conventional Wilkinson power divider. However, the bandpass filters in the proposed dividers require careful design because they may not be functional under certain conditions. For example, the odd-order coupled-line filters are not appropriate for impedance transformers in the proposed dividers. Besides, in the conventional unequal-split Wilkinson power divider, poor selectivity for each transmission path is usually a problem. To surmount this obstacle, the parallel coupled-line bandpass filter structure is utilized as an impedance transformer as well as a band selector for each transmission path in the proposed unequal-split Wilkinson power dividers. Using the even-order coupled-line filter transformers, this study proposes two types of unequal-split Wilkinson power dividers. The first type of the proposed dividers arranges two filter transformers near two output ports, respectively, and is capable of achieving a highly remarkable isolation between the two output ports and a good band selection in each transmission path. Specifically, not only the operating band but also the lower and higher stopbands can achieve highly favorable isolation for this type of divider. By arranging the load impedance of each port properly, the second type of the proposed dividers, which has only one filter transformer to be shared by each transmission path near the input port, is also proposed to provide effective isolation between two output ports and favorable selectivity in each transmission path.