在本論文中提出利用一組三埠帶通濾及兩組低通濾波器，取代傳統威爾京森分波器架構中的四分之一波長阻抗轉換器，製作成具寬止帶且帶通特性之分波器。藉由利用兩端短路的二分之一波長步階式阻抗共振器(Stepped-impedance resonator, SIR)，其兩端輸出信號有相同的振幅及相位略同，且兩輸出路徑共用一組帶通濾波器，所以只要一組三埠的帶通濾波器即可達到功率分配的功能，更可進一步的縮減電路面積，只要再額外使用一段70.7 ?的相位延遲線和隔離電阻，便可完成設計。其中，使用橢圓函數低通濾波器取代一段70.7 ?的相位延遲線，來進一步提升止帶壓抑的效果，故此分波器可達到相當寬的止帶並且縮短相位延遲線的長度，其20-dB止帶可達到22.2倍的操作中心頻率。 本論文提出設計四階之具寬止帶且帶通特性威爾京生分波器，此設計相較於二階電路除了有更好的選擇度，且提升了止帶壓抑效果，30-dB止帶可達到22.2倍的操作中心頻率，同時可驗證本論文提出之設計方法的可行性。 利用在步階式阻抗共振器兩輸出端加上二極體負載製作成可開關的分波器。藉由偏壓控制此二極體開或關，可改變分波器的輸出路徑，設計出可開關式的具寬止帶且帶通特性分波器，20-dB止帶可達到22.2倍的最低操作中心頻率。最後，在本論文中利用實作之電路驗證設計的方法是有效的。 A wide-stopband Wilkinson power divider with bandpass response is proposed. A 3-terminal, 2-pole bandpass filter and two lowpass filters are used to replace two quarter-wavelength transformer in the conventional Wilkinson power divider. By employing shorted-circuited half-wavelength resonator, the two output signals are of the same magnitude and phase. The two output paths share a bandpass filter. Hence, only one 3-terminal bandpass filter is used for power division. In this way, the circuit size could be further reduced. One can simply utilize two 70.7 ? delay lines with proper length and an isolation resistor to finish the design. However, the divider also utilizes microstrip elliptic-function lowpass filters. With negligible insertion loss in the passband, these lowpass filters not only generate wide stopband but also provide phase delay to shorten the two delay lines. The proposed divider features not only bandpass response but also a very wide stopband. For the upper stopband performance, the rejection level is greater than 20 dB up to 22.2f0. The design concept mention above can also be extended to realize a filter-based Wilkinson power divider in order to improve the selectivity and stopband rejection. For the upper stopband performance, the rejection level is greater than 30 dB up to 22.2f0. Stepped-impedance resonators with diodes loaded at two outputs are used to develop switchable power divider in this thesis. The p-i-n loaded diodes are used to independently control the channel of the divider. The 20-dB stopband extends up to 22.2 f0. Experiments are carried out to validate design concept of the proposed power divider.
