一般常用設計多工器的方法多為散布式耦合的饋入技術來設計多頻帶的多工器，因為這種設計方法不僅擁有較小的負載效應且不需要做額外的匹配電路來設計多頻帶的電路，但是因隨著多工器通帶的增加其面積亦增加，因此，提出利用直接饋入非對稱步階式阻抗共振而設計的寬通帶寬止帶之寬頻帶的濾波器，使用各種不同的半波長非對稱的步階式阻抗，利用非對稱步階式阻抗的阻抗比及電氣長度比可以控制共振器高階諧波的特性，故選定適當的比例將高階諧波的頻率控制在較低的頻率，再利用混合式耦合撐起寬頻通帶，接著用此濾波器架構當作基本單一的電路延伸設計出雙工器，並比較在耦合共振路徑中的地方設計一個非耦合的路徑與傳統一般平行耦合傳輸線的不同，並分析其傳輸極點、電流分析圖及負載效應，最後再基於此種設計及架構所設計出的雙工器具有寬頻帶寬止帶的特性，其設計出的通帶可達到50 %左右，20 dB止帶可達到7.0倍的最低操作頻率且在隔離度的部分可以達到28 dB以上，並利用實作電路驗證設計的方法是有效的 ◦;In general, the requirement of multiplexers applications, almost all of the multiplexers were used distributing coupling technique to design. Due to the low loading effect from distributing coupling technique, the circuits can obtain many channels without need of complicated matching network. Therefore, thesis presents wideband and wide stopband bandpass filter using tapping technique and asymmetric stepped impedance resonator. By using various dissimilar half-wavelength asymmetric stepped-impedance resonators (SIRs) and shunt open-circuited stubs, a wide stopband is achieved. The higher order mode frequencies can be determined by property choosing a suitable combination of impedance ratio and electrical length ratio of the asymmetric SIR. Parallel-coupled line with a meandering uncoupled section can enhance spurious suppression. And analyze transmission pole, Current distribution and load effect. Finally, on the basis of this structure of the diplexer with wideband and wide stopband characteristics, the bandwidth is reaches about 50 %. The 20-dB stopband extends up to 7.0 f0 the lowest operation center frequency and the isolation is better than 28 dB and the. Based on the design concept, the proposed diplexer is designed and fabricated with good agreement between simulations and measurements.
